The International Magazine on Banana and Plantain€¦ · The International Magazine on Banana and...

INFOMUSAINFOMUSAThe International Magazine on Banana and Plantain

INFOMUSA is published with the support of the Technical Center for Agricultural and Rural Cooperation (CTA)

CTA

Vol. 9 N° 2December 2000

IN THIS ISSUE

Screening Musa hybrids for resistance to Radopholus similis

Variability in the root systemcharacteristics of bananaaccording to genome groupand ploidy level

A new biological nematicide to protect the roots ofmicropropagated plantain

Proposed mechanisms on how Cavendish bananas arepredisposed to Fusarium wilt during hypoxia

Soil chemical parameters and incidence and intensity of Panama disease

Intensity of black and yellowSigatoka in cv. ‘Dominico Hartón’ subjected to irradiation by 60Co

Evaluation of banana bunchtrimming (cv. ‘Valery’)

Consumer acceptability of introduced bananas in Uganda

Corm decortication method for the multiplication of banana

Preliminary evaluation ofsome banana introductions in Kerala (India)

Morphological diversity of Musa balbisiana Colla in the Philippines

MusaNews

Thesis

Books etc.

Announcements

INIBAP News

PROMUSA News

FR

UITFUL N

ET

WORKING

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• FIFTE

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O

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1985

inibap

2000

Vol. 9, N° 2Cover photo:Banana is an important staple food in Uganda(Jean-Vincent Escalant, INIBAP)Publisher: International Network for the Impro-vement of Banana and PlantainManaging editor: Claudine PicqEditorial Committee: Emile Frison, Jean-Vincent Escalant,Suzanne Sharrock, Charlotte LustyPrinted in FranceISSN 1023-0076Editorial Office: INFOMUSA, INIBAP, Parc ScientifiqueAgropolis II, 34397 Montpellier Cedex5, France. Telephone + 33-(0)4 67 6113 02; Telefax: + 33-(0)4 67 61 03 34; E-mail: [email protected] are free for developingcountries readers. Article contributionsand letters to the editor are welcomed.Articles accepted for publication may beedited for length and clarity. INFOMUSAis not responsible for unsolicited mater-ial, however, every effort will be made torespond to queries. Please allow threemonths for replies. Unless accompaniedby a copyright notice, articles appearingin INFOMUSA may be quoted or repro-duced without charge, provided ac-knowledgement is given of the source.French-language and Spanish-languageeditions of INFOMUSA are also pub-lished.To avoid missing issues of INFOMUSA,notify the editorial office at least sixweeks in advance of a change of address.

Views expressed in articles arethose of the authors and do not nec-essarily reflect those of INIBAP.

INFOMUSA Vol. 9, N° 2

CONTENTS

Screening Musa hybrids for resistance to Radopholus similis . . . . . . . . . . . . . . . 3

Assessment of variability in the root system characteristics of banana(Musa spp.) according to genome group and ploidy level . . . . . . . . . . . . . . 4

Use of a new biological nematicide to protect the roots of plantain (Musa AAB) multiplied by micropropagation . . . . . . . . . . . . . . . . . . . . . . . . . 8

Proposed mechanism on how Cavendish bananas are predisposedto Fusarium wilt during hypoxia . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9

Soil chemical parameters in relation to the incidence and intensity of Panama disease . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13

Intensity of black Sigatoka (Mycosphaerella fijiensis Morelet) and yellowSigatoka (Mycosphaerella musicola Leach) in Musa AAB cv. ‘Dominico hartón’ subjected to irradiation by 60Co . . . . . . . . . . . . . . . . . . . 16

Methodological consideration in ths evaluation of banana bunch trimming (Musa AAA, cv. ‘Valery‘). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19

Consumer acceptability of introduced bananas in Uganda. . . . . . . . . . . . . . . . 22

Corm decortication method for the multiplication of banana . . . . . . . . . . . . . 26

Preliminary evaluation of some banana introductions in Kerala (India) . . . . . 27

Morphological diversity of Musa balbisiana Colla in the Philippines . . . . . . . . 28

Musa News . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30

Thesis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32

Announcements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33

INIBAP News . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34

Books etc . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40

PROMUSA News . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . I to XVI

The mission of the International Network for the Improvement of Banana and Plan-tain is to sustainably increase the productivity of banana and plantain grown onsmallholdings for domestic consumption and for local and export markets.The Programme has four specific objectives:• To organize and coordinate a global research effort on banana and plantain,

aimed at the development, evaluation and dissemination of improved cultivarsand at the conservation and use of Musa diversity

• To promote and strengthen collaboration and partnerships in banana-related re-search activities at the national, regional and global levels

• To strengthen the ability of NARS to conduct research and development activitieson bananas and plantains

• To coordinate, facilitate and support the production, collection and exchange ofinformation and documentation related to banana and plantain.

INIBAP is a programme of the International Plant Genetic Resources Institute(IPGRI), a Future Harvest center.

INFOMUSAINFOMUSAThe International Magazine on Banana and Plantain

INFOMUSA is published with the support of the Technical Center for Agricultural and Rural Cooperation (CTA)

CTA

Vol. 9 N° 2December 2000

IN THIS ISSUE


Variability in the root systemcharacteristics of bananaaccording to genome groupand ploidy level

A new biological nematicide to protect the roots ofmicropropagated plantain

Proposed mechanisms on how Cavendish bananas arepredisposed to Fusarium wilt during hypoxia

Soil chemical parameters and incidence and intensity of Panama disease

Intensity of black and yellowSigatoka in cv. ‘Dominico Hartón’ subjected to irradiation by 60Co

Evaluation of banana bunchtrimming (cv. ‘Valery’)



Preliminary evaluation ofsome banana introductions in Kerala (India)

Morphological diversity of Musa balbisiana Colla in the Philippines

MusaNews

Thesis

Books etc.

Announcements

INIBAP News

PROMUSA News

FR

UITFUL N

ET

WORKING

�

• FIFTE

EN YEARS

O

F •

�

1985

inibap

2000

Carine Dochez, Paul R. Speijer†, John Hartman†, Dirk Vuylsteke†

and Dirk De Waele

Plant parasitic nematodes are amajor constraint to sustainableMusa production (Stover and

Simmonds 1987). In Uganda, which isthe world‘s largest producer of EastAfrican highland bananas (Musa spp.,AAA group) (Lescot 1998), nematodeshave been identified as a major factorcontributing to declining production(Speijer et al. 1999). The most destruc-tive nematode attacking bananas in thetropics is Radopholus similis (Cobb)Thorne (Gowen 1993), which was ac-cordingly used as the test species inthis screening procedure.

Nematodes can be controlled withchemicals, but these may have adverseenvironmental effects and the use ofnematicides is too expensive and theproducts too dangerous for subsistencefarmers. Breeding for host plant resis-tance is a promising strategy for con-trolling nematodes (Speijer and DeWaele 1997). However, screening newhybrids in the field is very time- andspace-consuming. Therefore, an earlyand rapid method for screening bananagermplasm for nematode resistance,based on inoculation of individual roots,was used (De Schutter et al., in prepa-ration).

Materials and methodsScreen-house experiments were estab-lished in Central Uganda at the Easternand Southern Africa Regional Centre ofthe International Institute of TropicalAgriculture (IITA-ESARC), SendusuFarm, Namulonge. The station is at analtitude of 1150 m asl and is represen-tative for the East African highland ba-nanas.

Tested cultivars included the refer-ence cultivars Yangambi km 5 (MusaAAA group), which is highly resistant toRadopholus similis , Gros Michel(Musa AAA, partially resistant to R.similis) and Valery (Musa AAA, suscep-tible to R. similis).

Several hybrids were selected by theIITA-ESARC breeding programme fortesting, including: the plantain deriveddiploid hybrids TMP2x 2521S-31,TMP2x-47, and TMP2x-50; the bananaderived diploid hybrids TMB2x 1411S-2,

TMB2x 1411S-10, TMB2x 2559S-1 andTMB2x 2559S-2; the ‘Pisang Awak’ de-rived tetraploid hybrid TMBx 2094S-1;and the East African Highland Bananaderived tetraploid hybrid TMHx 660K-1.

Nematode inoculum was obtainedfrom carrot (Daucus carota L.) disccultures (Pinochet et al. 1995). Carrotswere surface-sterilized by sprayingthem with 96% ethanol followed byflaming, peeled, cut in discs (3 mmthick) and placed in 35 mm-diameterPetri dishes. Nematodes were surface-sterilized with aqueous streptomycinsulphate (2000 ppm) for 6 hours fol-lowed by three rinses with sterile dis-tilled water. About 100 nematodes, in10 µl of water, were placed on each car-rot disc. The Petri dishes were sealedwith parafilm and incubated at 28°C inthe dark. Nematodes were sub-culturedonto fresh carrots every 5 to 7 weeks.Inoculum was prepared by rinsing thePetri dishes containing the carrot discswith sterile distilled water and collect-ing the nematodes in a test tube.

All Musa genotypes were planted inwooden boxes containing steam-steril-ized sawdust. Each box contained 9suckers, which were pared and hotwater-treated (Colbran 1967). Fourweeks after planting, three roots wereselected from each sucker. Every se-lected root was carefully excavated andat a distance of 5 cm from the rhizome,a small plastic container was placedaround the root. Inoculation was doneby pouring a suspension of 50 femalesof R. similis on each individual root.

The root and plastic container werethen covered with steam-sterilizedsand. Eight weeks after inoculation, theinoculated roots were harvested.

The harvested roots were washed andmacerated in a blender for 10 seconds.Nematodes were extracted overnightusing a modified Baermann funneltechnique (Hooper 1990). Nematodeswere concentrated by collecting themon a 20 mm sieve. All vermiform devel-opmental stages and sexes werecounted. For each cultivar the repro-duction ratio (final population/initialpopulation) of R. similis was calcu-lated. Orthogonal contrasts (SAS 1997)of the test materials to the referencecultivars Yangambi km 5 and Valerywere run to compare the mean repro-duction ratios.

Results and discussionTable 1 shows the reproduction ratio ofR. similis on the different cultivars,while Table 2 shows the orthogonal con-trasts between the test cultivars andthe resistant and susceptible checks.The nematodes on all the other culti-vars showed a lower reproduction ratiothan on Valery (Tables 1 and 2). Thegenotypes Gros Michel, TMP2x 2521S-31 and 47, TMB2x 1411S-10, TMBx2094S-1, TMHx 660K-1 and TMB2x2569S-2 supported a reproduction ratiothat was not significantly different fromthat on Yangambi km 5. Genotypes witha reproduction ratio not statisticallydifferent from Yangambi Km5 supportlow densities and are therefore promis-

INFOMUSA — Vol 9, N° 2 3


Genetic resources Early tests for selection

Table 1. Reproduction ratio of Radopholus similis on individual roots of 12 Musagenotypes, 8 weeks after inoculation with a suspension containing 50 females of R. similis

Genotype Parents Pf Rr1 = Pf2/Pi3

Yangambi km5 1 0.02

Gros Michel 82 1.64

Valery 883 17.66

TMB2x 1411S-2* TMB2x 7197-2 x TMB2x 9839-1 427 8.54

TMB2x 1411S-10* TMB2x 7197-2 x TMB2x 9839-1 10 0.20

TMB2x 2569S-1* TMB2x 7197-2 x TMB2x 9128-3 2 0.04

TMB2x 2569S-2* TMB2x 7197-2 x TMB2x 9128-3 491 9.82

TMBx 2094S-1* Kayinja x TMB2x 7197-2 73 1.46

TMP2x 2521S-31* TMP2x 1518 x TMB2x 8075-3 66 1.32

TMP2x 2521S-47* TMP2x 1518 x TMB2x 8075-3 60 1.20

TMP2x 2521S-50* TMP2x 1518 x TMB2x 8075-3 0.3 0.006

TMHx 660K-1 Enzirabahima x Calcutta 4 99 1.981 Rr = Reproduction ratio (final population/initial population).2 Pf = Final population including all vermiform stages and sexes.3 Pi = Initial population, 50 females of R. similis.

* Hybrids with Pisang Jari Buaya in their pedigree.

ing genotypes for further evaluation.Except for the hybrid TMHx 660K-1, allthe other hybrids have Pisang JariBuaya (Musa AA) in their pedigree,which is highly resistant to R. similis(Pinochet 1988).

AcknowledgementsFinancial support by the Flemish Asso-ciation for Development Cooperationand Technical Assistance (VVOB) andby the Belgian Administration for De-velopment Cooperation (BADC) isgratefully acknowledged. The authorswish to thank Mrs Pamela Mpirirwe andMs Christine Kajumba for technical as-sistance. This is IITA manuscript num-ber IITA/00/JA/29. ■

ReferencesColbran R.C. 1967. Hot water tank for treatment of

banana planting material. Queensland Depart-ment of Primary Industries, Brisbane. Advisoryleaflets Division of Plant Industry 9(24): 4.

De Schutter B., P.R. Speijer, C. Dochez, A. Ten-kouano & D. De Waele. (in preparation). Scree-ning of Musa germplasm for resistance to nema-todes by inoculating individual roots.

Gowen S.R. 1993. Yield losses caused by nematodeson different banana varieties and some manage-ment techniques appropriate for farmers inAfrica. Pp. 199-208 in Biological and integratedcontrol of highland banana and plantain pestsand diseases. Proceedings of a research coordi-nation meeting. Cotonou, Bénin, 12-14 November1991 (C.S. Gold & B. Gemmill, eds.). Internatio-nal Institute of Tropical Agriculture, Ibadan, Ni-geria.

Hooper D.J. 1990. Extraction and processing ofplant soil nematodes. Pp. 137-180 in Plant para-sitic nematodes in subtropical and tropical agri-culture (M. Luc, R.A. Sikora & J. Bridge, eds).CAB International, Wallingford, UK.

Lescot T. 1998. Banana. Little-known wealth of va-riety. Fruitrop 51: 8-11.

Pinochet J. 1988. Comments on the difficulty inbreeding bananas and plantains for resistance tonematodes. Revue de Nématologie 11(1): 3-5.

Pinochet J., C. Fernandez & J.L. Sarah. 1995. In-fluence of temperature on in vitro reproductionof Pratylenchus coffeae, P. goodeyi and Rado-pholus similis. Fundamental and Applied Nema-tology 18(4): 391-392.

SAS. 1997. SAS guide for personal computers. 6thed. SAS Institute Inc., Cary, North Carolina, USA.

Speijer P.R. & D. De Waele. 1997. Screening ofMusa germplasm for resistance and tolerance tonematodes. INIBAP Technical Guidelines 1. In-ternational Plant Genetic Resources Institute,Rome, Italy; International Network for the Im-provement of Banana and Plantain, Montpellier,France; ACP-EU Technical Centre for Agricultu-ral and Rural Cooperation, Wageningen, The Ne-therlands. 47 p.

Speijer P.R., C. Kajumba & F. Ssango. 1999. EastAfrican highland banana production as influen-

ced by nematodes and crop management inUganda. International Journal of Pest Manage-ment 45: 41-49.

Stover R.H. & N.W. Simmonds. 1987. Banana. 3rd ed. Longman Scientific and Technical, London, UK.

This work was carried out by Carine Dochez, Paul R.Speijer, John Hartman and Dirk Vuylsteke fromthe International Institute of Tropical Agriculture–Eas-tern and Southern Africa Regional Centre (IITA-ESARC), PO Box 7878, Kampala, Uganda, and DirkDe Waele from the Laboratory of Tropical Crop Im-provement, Catholic University of Leuven (KUL), Kas-teelpark Arenberg 13, 3001 Leuven, Belgium.

4 INFOMUSA — Vol 9, N° 2

Table 2. Orthogonal contrasts between Yangambi km 5 (R. similis-resistant), Valery(R. similis-susceptible) and the other cultivars.

Cultivars Contrast with Yangambi km5 Contrast with Valery

Yangambi km5 ***

Gros Michel Ns ***

Valery ***

TMB2x 1411S-2 ** **

TMB2x 1411S-10 Ns ***

TMB2x 2569S-1 ** **

TMB2x 2569S-2 Ns ***

TMBx 2094S-1 Ns ***

TMP2x 2521S-31 Ns ***

TMP2x 2521S-47 Ns ***

TMP2x 2521S-50 * ***

TMHx 660K-1 Ns ***Ns = Contrast not significant at P > 0.05.

*** Contrast significant at P = 0.001.

** Contrast significant at P = 0.01.

* Contrast significant at P = 0.05.

G. Blomme, R. Swennen and A. Tenkouano

Genetic improvement in root traitsof crop species requires knowl-edge of intraspecies variability in

root characteristics (O’Toole and Bland1987). Genotypic differences in rootsize have been reported for maize (Zeamays L.) (Pan et al. 1985, Aina and

Fapohunda 1986, Mackay and Barber1986), barley (Hordeum vulgare L.)(Hackett, 1968), wheat (Triticum aes-tivum L.) (Hurd 1968), tomatoes (Ly-copersicon esculentum Mill.) andbeans (Phaseolus vulgaris L.) (Zobel1975), rice (Oryza sativa L.) (Nicou etal . 1970, Reyniers et al . 1975,Ekanayake et al. 1985a, 1985b) and sev-eral other species (O’Toole and Band1987).

Genotypic differences in Musa spp.root traits have been investigated underhydroponic conditions (Swennen 1984,Swennen et al. 1986) with the conclu-sion that dessert bananas had a largerroot system than plantains. In a similarstudy, genotypic differences in lateralroot initiation were also observed(Draye et al. 1999).

Ploidy level may influence the size ofdifferent plant parts in Musa species

Assessment of variability in the root systemcharacteristics of banana (Musa spp.) according to genome group and ploidy level

Physiology Influence of ploidy

(Simmonds 1962 and 1966, Vandenhoutet al. 1995), but no systematic study onthe effect of ploidy level and genomegroup on root traits of field grownplants has been carried out.

The objective of this study was to as-sess the relative contribution of ploidystatus and genome composition to thevariability of root traits in Musa.

Materials and methodsThis study was carried out at the IITAHigh Rainfall station at Onne in south-eastern Nigeria (4°42’ N, 7°10’ E, 5masl). Its soil is an ultisol derived fromcoastal sediments, well drained butpoor in nutrients and with a pH of 4.3 in1:1 H2O. The average annual rainfall is2,400 mm distributed monomodallyfrom February until November. Detailsof the site have been described by Ortizet al. (1997).

Eighteen genotypes (Table 1) belong-ing to 5 genomic groups and 3 ploidy

levels of banana and plantain (Musaspp.) were assessed at flower emer-gence. In vitro-derived plants were pro-duced following standard shoot-tip cul-ture techniques (Vuylsteke 1989,Vuylsteke 1998). Rooted plantlets weretransferred to polybags (height = 25cm, circumference = 44 cm) in a green-house nursery (Vuylsteke and Talengera1998, Vuylsteke 1998) and transplantedto the field during June 1996, six weeksafter acclimatization.

The trial site, which had been undergrass fallow for a period of 8 years, wasmanually prepared in order to avoid soildisturbance. Plants were fertilized withmuriate of potassium (a.i. K20, 60% K)at a rate of 600 g plant-1 year-1, andUrea (47% N) at a rate of 300 g plant-1

year-1, split over 6 equal applicationsduring the rainy season. No mulch wasapplied. The experimental area wastreated with the nematicide Nemacur(a.i. fenamiphos) at a rate of 15 g plant-

1 (3 treatments year-1) to reduce nema-tode infestation. The fungicide Bayfidan(a.i. triadimenol) was applied threetimes per year at a rate of 3.6 ml plant-1

to control the leaf spot disease blacksigatoka (Mycosphaerella fijiensisMorelet). Plants were irrigated duringthe dry season at a rate of 100 mmmonth-1.

The field layout was a randomizedcomplete block design with two replica-tions of two plants per genotype. Toavoid overlapping of adjacent root sys-tems, plant spacing was 4 m x 4 m. Theplants were completely excavated andthe characteristics measured includedplant height (PH, cm), number ofleaves (NL), pseudostem circumferenceat soil level (PC, cm) and height of thetallest sucker (HS, cm). In addition,leaf area (LA, cm2) was calculated ac-cording to Obiefuna and Ndubizu(1979). Corm characteristics measuredwere fresh corm weight (CW, g), cormheight (CH, cm) and widest width ofthe corm (WW, cm). The number ofsuckers (NS) on the corm werecounted. Root characteristics includedthe number of adventitious roots orcord roots (NR), root dry weight (DR, g)and the average basal diameter of thecord roots (AD, mm) measured with aVernier Calliper. The cord root length(LR, cm) was measured using the lineintersect method (Newman 1966, Ten-nant 1975). Other root system charac-teristics were total dry weight (TD, g)of the mat (i.e. plant crop and suckers)and total cord root length of the mat(TL, cm). Aerial growth, corm develop-ment and root system growth character-istics were also measured for the tallestsucker.

Statistical analysis was carried outusing the SAS statistical package (SAS,1989). Variability of the differentgrowth characteristics was assessedusing PROC GLM in SAS. Total pheno-


Table 1. Name, genome, ploidy level, type and suckering behaviour of thegenotypes assessed in this study.

Name Genome Ploidy level Type Suckering

Niyarma Yik AA 2 Musa acuminata banksii Non regulated

Calcutta 4 AA 2 Musa acuminata burmannica Non regulated

Pahang AA 2 Musa acuminata malaccensis Non regulated

Pisang J. Buaya AA 2 Musa acuminata microcarpa Non regulated

Pisang Madu AA 2 Musa acuminata microcarpa Non regulated

Tjau Lagada AA 2 Musa acuminata microcarpa Non regulated

Yangambi km5 AAA 3 Dessert banana Regulated

Valery AAA 3 Dessert banana Regulated

Obino l’Ewai AAB 3 Plantain Inhibited

Agbagba AAB 3 Plantain Inhibited

Pelipita ABB 3 Cooking banana Regulated

Cardaba ABB 3 Cooking banana Regulated

Fougamou ABB 3 Cooking banana Regulated

TMPx 2796-5 AAB x AA 4 Plantain hybrid (Bobby Tannap x Pisang lilin) Regulated

TMPx 7152-2 AAB x AA 4 Plantain hybrid (Mbi Egome 1 x Calcutta 4) Regulated

TMPx 548-9 AAB x AA 4 Plantain hybrid (Obino l’Ewai x Calcutta 4) Regulated

TMPx 5511-2 AAB x AA 4 Plantain hybrid (Obino l’Ewai x Calcutta 4) Inhibited

TMPx 1658-4 AAB x AA 4 Plantain hybrid (Obino l’Ewai x Pisang lilin) Regulated

Table 2. Mean square and significance tests of different quantitative traits of plants at flower emergence.

Trait#

Source of variation Df LA PH CW NS HS DR NR

Replication 1 1017416013 392 2737103 1 2088 15212 201

Ploidy level 2 7547029458*** 5680*** 12051416*** 41** 28298*** 93565*** 20537***

Genome group 2 2608843147** 6364*** 11752654*** 65*** 7595* 45845*** 8463**

Genotype 13 2106141878*** 3575*** 8429250*** 33*** 10571*** 18524*** 2874*

Residual 50 363318642 321 1109510 6 1526 4442 1330

LR AD TD TL % MPDR % MPLR DTFL

Replication 1 4563021 0,04 24291 9812 12 198 1197

Ploidy level 2 53138430*** 7,83** 18217 54977396 4497*** 3503*** 48142***

Genome group 2 4179499 1,49** 62806 34364239 1090*** 1217*** 2297

Genotype 13 10764435* 0,38* 128050***133333288*** 404** 287* 10774***

Residual 50 4845881 0,19 23054 38834528 134 146 1741#: Df: degrees of freedom; LA: leaf area (m2); PH: plant height (cm); CW: corm weight (g); NS: number of suckers; HS: height of the tallest sucker (cm); DR: root dry weight (g); NR: number of cordroots; LR: cord root length (cm); AD: average basal cord root diameter (mm); TD: total root dry weight of the mat (g); TL: total length of the cord roots of the mat (cm); %MPDR: percentage root dryweight of the plant crop to the mat; %MPLR: percentage cord root length of the plant crop to the mat; DTFL: days to flower emergence.

*, **, *** Significant at P < 0.05, 0.01 and 0.001, respectively.

typic variance was partitioned accord-ing to the following sources of variation:replication, ploidy level, genome groupand genotype.

Results and discussionThere was a significant effect of ploidylevel on the different characteristics,except for root dry weight and cord rootlength of the mat (Table 2). Generally,with increasing ploidy level the magni-tude of plant characteristics tends toincrease. For example, the tetraploidshad the highest values for leaf area,plant height, corm fresh weight, plantcrop root traits and their respectivedaily growth rates (Table 3). The effectof genotype was significant for all as-sessed traits, while the effect ofgenome group was significant for allshoot and several root traits.

Simmonds (1962) reported also thatfruit sizes increased with increasingploidy levels, while Vandenhout et al.(1995) noted the same for the stomatasize. Apparently the increased chromo-some number resulted in larger cellscausing an increase in the size of theplant organs. Vakili (1967) reportedthat colchicine derived tetraploids fromM. balbisiana were taller and more ro-

bust but had slower growth rate, fewersuckers and scantier root systems thandiploids. Contrary to these observa-tions, higher daily growth rates andlarger plant crop root systems were ob-served with increasing ploidy level inthis study (Table 3). Cord root diameterincreased with higher ploidy level(Table 3) confirming observations madeby Monnet and Charpentier (1965).

There was an increase in sucker de-velopment with decreasing ploidy level.All diploid bananas had a non-regulat-ing suckering behaviour (i.e. all suckersgrow vigorously) resulting in a faster cy-cling, while the studied triploids andtetraploids had a regulated (i.e. 2 or 3suckers grow vigorously) or an inhibitedsuckering (i.e. no sucker grows vigor-ously) (Table 1). For example, the plantcrop accounted for only 45% of the rootdry weight of the mat for the diploid ba-nanas indicating a strong suckergrowth. Conversely, the plantains, thecooking bananas and the tetraploidplantain hybrids had more than 60% ofthe root system accounted for by theplant crop.

Blomme and Ortiz (1996) reportedsignificant positive correlation betweenroot and shoot growth characteristics

during the vegetative stage, indicatingthat vigorously growing plants also hadlarger root systems. In this study therewas a clear relationship between shootand root growth according to genomegroup. For example, diploids (AAgenomes) and dessert bananas (AAA)had low values for most root and shootgrowth characteristics, while plantains(AAB), cooking bananas (ABB) andtetraploid plantain hybrids (AAAB) hadhigher values (Tables 3 and 4). The lowvalues for shoot and root traits of thedessert banana group is probably due tothe inclusion of the semi-dwarf variety‘Valery’.

In this study, there was a tendency ofincreased shoot and root vigor for thehigher ploidy levels. Conversely, suckerdevelopment and thus perenniality wasenhanced with decreasing ploidy level.

AcknowledgementsFinancial support by the Flemish Asso-ciation for Development Cooperationand Technical Assistance (V.V.O.B.:Vlaamse Vereniging voor Ontwikkel-ingssamenwerking en Technische Bijs-tand) and the Directorate General forInternational Cooperation (DGIC, Bel-gium) is gratefully acknowledged. Theauthors thank Miss Lynda Onyeukwufor helping with the data collection. ■

ReferencesAina P.O.& H.O. Fapohunda. 1986. Plant Soil 94:

257-265.Blomme G. & R. Ortiz. 1996. Preliminary evaluation

of variability in Musa root system development.Pp. 51-52. In Biology of root formation and deve-lopment (A. Altman ed.). Plenum PublishingCompany, New York.

Draye X., B. Delvaux & R. Swennen. 1999. Distribu-tion of lateral root primordia in root tips ofMusa. Annals of Botany 84: 393-400.

Ekanayake I.J., D.P. Garrity, T.M. Masajo & J.C.O’Toole. 1985b. Root pulling resistance in rice:Inheritance and association with drought resis-tance. Euphytica 34: 903-913.

Ekanayake I.J., J.C. O’Toole, D.P. Garrity & T.M.Masajo. 1985a. Inheritance of root charactersand their relations to drought resistance in rice.Crop. Sci. 25: 927-933.

Hackett C. 1968. A study of the root system of Bar-ley. I. Effects of nutrition on two varieties. NewPhytol. 67: 287-299.

Hurd E.A. 1968. Growth of roots of seven varieties ofspring wheat at high and low moisture levels.Agron. J. 60: 201-205.

Mackay A.D. & S.A. Barber. 1986 Effect of nitrogenon root growth of two corn genotypes in the field.Agron. J. 78: 699-703.

Monnet J. & J.M. Charpentier. 1965. Le diamètredes racines adventives primaires des bananiersen fonction de leur degré de polyploïdie. Fruits20: 171-173.


Table 3. Musa spp. growth characteristics at flower emergence according to ploidylevel.

Ploidy level

Trait# 2 3 4

LA 92 635 ± 6 617 78 968 ± 5 290 115 547 ± 5 366

NL 13 ± 0,4 10 ± 0,6 14 ± 0,5

PH 228 ± 8 248 ± 7 260 ± 5

PC 53 ± 2 63 ± 2 63 ± 1

CW 4 135 ± 444 5 312 ± 274 5 498 ± 344

CH 24 ± 1 22 ± 1 20 ± 1

WW 16 ± 1 20 ± 1 21 ± 1

NS 13 ± 1 11 ± 1 10 ± 0,5

HS 161 ± 15 141 ± 12 90 ± 8

DR 212 ± 15 281 ± 22 343 ± 19

NR 122 ± 9 162 ± 9 182 ± 9

LR 5 807 ± 571 6 136 ± 365 8 707 ± 618

AD 4,53 ± 0,13 5,34 ± 0,11 5,70 ± 0,07

TD 533 ± 59 513 ± 33 475 ± 31

TL 15 236 ± 2 173 12 468 ± 1 064 12 760 ± 1 098

% MPDR 45 ± 3 56 ± 3 74 ± 2

% MPLR 46 ± 3 53 ± 3 71 ± 3

DTFL 381 ± 16 348 ± 12 288 ± 6

LA/DTFL 242 ± 14 237 ± 19 406 ± 22

PH/DTFL 0,61 ± 0,02 0,73 ± 0,03 0,91 ± 0,02

CW/DTFL 11 ± 1 16 ± 1 19 ± 1

HS/DTFL 0,44 ± 0,04 0,41 ± 0,04 0,31 ± 0,03

DR/DTFL 0,56 ± 0,04 0,84 ± 0,08 1,21 ± 0,07

NR/DTFL 0,32 ± 0,02 0,49 ± 0,04 0,64 ± 0,04

LR/DTFL 15 ± 1 18 ± 1 31 ± 2

TD/DTFL 1,39 ± 0,13 1,50 ± 0,10 1,67 ± 0,12

TL/DTFL 39 ± 5 36 ± 3 45 ± 4#: see Table 1; NL: number of leaves; PC: pseudostem circumference (cm); CH: corm height (cm); WW: corm widest width (cm).

Newman E.I. 1966. A method of estimating the totallength of root in a sample. J. Appl. Ecol. 3: 139-145.

Nicou R., L. Seguy & G. Haddad. 1970. Comparaisonde l’enracinement de quatre variétés de riz plu-vial en présence ou absence de travail du sol.L’Agronomie tropicale 25: 639-659.

Obiefuna J.C. & T.O.C. Ndubizu. 1979. Estimatingleaf area of plantain. Sci. Hortic. 11: 31-36.

Ortiz R., P.D. Austin & D. Vuylsteke. 1997. IITA highrainfall station: Twenty years of research for sus-tainable agriculture in the West African HumidForest. HortScience 32(6): 969-972.

O’Toole J.C. & W.L. Bland. 1987. Genotypic varia-tion in crop plant root systems. Adv. Agron. 41:91-145.

Pan W.L., W.A. Jackson & R.H. Moll. 1985. J. Exp.Bot. 36: 1341-1351.

Reyniers F.N., J.M. Kalms & J. Ridders. 1975. Etudedu comportement de deux types de variétés deriz selon leur alimentation hydrique. I. Etude desfacteurs permettant d’esquiver la sécheresse.Rapp. Inst. rech. agron. trop. (IRAT), Côted’Ivoire.

SAS Institute, Inc. 1989. SAS/STAT user’s guide,version 6, 4th ed., Vol. 1. Cary, N.C.: SAS InstituteInc.

Simmonds N.W. 1962. The evolution of bananas.Longman. London.

Simmonds N.W. 1966. Bananas. Tropical AgricultureSeries, Longman, London.

Swennen R. 1984. A physiological study of the suc-kering behaviour in plantain (Musa cv. AAB).Ph. D. thesis, Dissertationes de Agriculturan°132, Faculty of Agriculture, Katholieke Univer-siteit Leuven, 180 pp.

Swennen R., E.A. De Langhe, J. Janssen & D. Deco-ene. 1986. Study of the root development of someMusa cultivars in hydroponics. Fruits 41: 515-524.

Tennant D. 1975. A test of a modified line intersectmethod of estimating root length. J. Ecol. 63:995-1001.

Vakili N.G. 1967. The experimental formation of po-lyploidy and its effects in the genus Musa Am. J.Bot. 54: 24-36.

Vandenhout H., R. Ortiz, D. Vuylsteke, R. Swennen& K.V. Bai. 1995. Effect of ploidy on stomatal andother quantitative traits in plantain and bananahybrids. Euphytica 83: 117-122.

Vuylsteke D. 1989. Shoot-tip culture for the propa-gation, conservation, and exchange of Musagermplasm. Practical manuals for handling cropgermplasm in vitro 2. International Board forPlant Genetic Resources, Rome. 56 pp.

Vuylsteke D. 1998. Shoot-tip culture for the propa-gation, conservation, and distribution of Musagermplasm. International Institute of TropicalAgriculture, Ibadan, Nigeria. 82 pp.

Vuylsteke D. & D. Talengera. 1998. Postflask Mana-gement of Micropropagated Bananas and Plan-tains. A manual on how to handle tissue-cultu-

red banana and plantain plants. InternationalInstitute of Tropical Agriculture, Ibadan, Nige-ria. 15 pp.

Zobel R.W. 1975. The genetics of root development.Pp. 261-275 in The development and function ofroots (G. Torrey & D.C. Clarkson, eds.). Acade-mic Press. London and New York.

G. Blomme* and A. Tenkouano work at the CropImprovement Division, International Institute of Tropi-cal Agriculture (IITA), Onne High Rainfall Station, L.W. Lambourn & Co. Carolyn House, 26 DingwallRoad, Croydon, CR9 3EE, England and R. Swennenat the Laboratory of Tropical Crop Improvement, Ca-tholic University of Leuven (K.U.Leuven), KasteelparkArenberg 13, 3001 Leuven, Belgium.* Guy Blomme is currently working in Kampala,Uganda as the INIBAP assistant regional coordinatorfor East and Southern Africa.


Table 4. Musa growth characteristics at flower emergence for the triploid genome groups

Genome group

Trait # AAA AAB ABB

LA 58 208 ± 9 730 92 365 ± 5 888 85 513 ± 7 710

NL 8 ± 1 11 ± 0,5 12 ± 0,9

PH 215 ± 11 257 ± 8 268 ± 8

PC 55 ± 2 62 ± 1 69 ± 2

CW 3 945 ± 354 6 285 ± 290 5 662 ± 369

CH 23 ± 2 22 ± 1 22 ± 1

WW 17 ± 1 22 ± 1 20 ± 1

NS 14 ± 1 13 ± 1 8 ± 1

HS 165 ± 23 106 ± 10 150 ± 22

DR 220 ± 30 254 ± 31 361 ± 39

NR 135 ± 10 151 ± 9 195 ± 16

LR 5 285 ± 793 6 465 ± 397 6 599 ± 618

AD 4.9 ± 0.1 5.8 ± 0.2 5.3 ± 0.1

TD 556 ± 81 409 ± 18 567 ± 45

TL 14 883 ± 2 647 11 278 ± 1 358 11 379 ± 1 266

% MPDR 43 ± 5 62 ± 7 64 ± 4

% MPLR 39 ± 5 61 ± 5 60 ± 5

DTFL 368 ± 24 338 ± 9 340 ± 25

LA/DTFL 168 ± 35 276 ± 20 264 ± 32

PH/DTFL 0.61 ± 0.06 0.77 ± 0.04 0.82 ± 0.06

CW/DTFL 11 ± 1 19 ± 1 17 ± 2

HS/DTFL 0.45 ± 0.06 0.32 ± 0.03 0.46 ± 0.07

DR/DTFL 0.60 ± 0.07 0.77 ± 0.11 1.13 ± 0.15

NR/DTFL 0.38 ± 0.05 0.45 ± 0.03 0.61 ± 0.08

LR/DTFL 15 ± 2 19 ± 1 20 ± 2

TD/DTFL 1.50 ± 0.19 1.21 ± 0.05 1.75 ± 0.17

TL/DTFL 40 ± 7 33 ± 3 34 ± 3#: see Tables 2 and 3.

Lazaro L. Castellanos Lopez, JorgeLopez Torrez, Julian Gonzalez

Rodriguez. Sergio Rodriguez Moralesand José De La C. Ventura Martín

The cultivation of bananas andplantains represents substantialfood and economic resources for a

large proportion of the world’s popula-tion, mainly in the developing countriesin Asia, Africa and Latin America. Al-though conventional propagation meth-ods are still used in many of these coun-tries, micropropagation has gainedpopularity in recent years as an innova-tive alternative in multiplication.

Indeed, in vitro culture makes it pos-sible to produce disease and pest-freeplants for transfer to the field. However,the plants are still very delicate attransplantation, making them suscepti-ble to plant parasitic nematodes, whichsometimes cause considerable yieldlosses, as in the case of Meloydoginespp. These losses can be almost com-pletely eliminated if the soil is disin-fected before planting or if planting isperformed in nematode-free soil. How-ever, this is not very easy to achieve. Onthe one hand, the application of chemi-cal nematicides considerably affectsthe production process and destroys theecological balance of the soil, and onthe other hand the methods for the de-tection of nematodes in the soil are nottotally reliable. Nematodes are practi-

cally impossible to detect when the soilpest population is very small. As a re-sult, farmers may be inclined to use in-fested land that appears to be com-pletely free of nematodes andconsidered unworthy of nematicide ap-plication. However, as months go by, itwill be seen that nematode populationsare indeed present and that the de-fenceless roots of the plantlets are ei-ther practically non-existent or are cov-ered with thick nodules.

The use of nematode-trapping fungibelonging to different genera such asHarposporium sp., Dactylella spp.,Stylopage sp., Dactylaria spp., Cate-naria sp. and Arthrobotrys sp. (Dud-dington 1956, Cortado 1968, Generalao1986, Stirling 1988, Persson 1997) ap-pears to be a promising alternative foraddressing this problem.

These organisms have several kindsof advantage in the biological control ofnematodes, including:• their ability to trap and eliminate a

large number of nematode speciesusing specialized capture structuresor organs to trap moving parasites(loops, contractile or not; nets; stickystructures and other methods). Thisis a particularly interesting feature ascontrol is thus performed before thenematode penetrates the root andcauses damage there;

• their biological cycle involves twophases: 1) a saprophytic phase duringwhich they use only the soil organic

matter as a source of carbon (energy)and aminoacids (nitrogen), and 2) aparasite phase during which theyfeed only on the organic matter ofcaptured nematodes (Stirling 1988,Persson 1997). It has been observedthat in the presence of nematodesthey are capable of changing rapidlyfrom the saprophytic to the parasitephase and that this also triggersspore germination and the develop-ment of capture organs;

• their ability to produce substancesthat attract the parasites; this furtherincreases their control effectivenesswith regard to the latter;

• some of these fungi release a largequantity of resistance spores, makingit possible to formulate them in dif-ferent ways.INIVIT maintains a stock of nemato-

phagous and/or nematode parasitefungi isolated from Cuban soils plantedwith banana and plantain. Many havealready been characterized and havedisplayed considerable pathogenicitywith regard to the main nematodespecies infecting Cuban banana crops.

The introduction of nematophagousfungi in the rhizosphere of tissue cul-ture plants would make it possible toreduce or eliminate production losses,to reduce the costs involved in the useof chemicals and to conserve soils,since the protection of the roots ofplantlets would be achieved in a nat-ural and ecological manner. This wasthe reason for undertaking research onthe strain INIVIT 99-1 TPB of Arthro-botrys sp. with regard to protection ofthe roots of CEMSA 3/4 plantain(MusaAAB) multiplied by micropropagation.

Material and methodsThe research was conducted at INIVITin the tissue culture plant weaningzone in 1999.

In vitro plants of the CEMSA 3/4plantain clone (Musa spp. AAB) wereused and the work concerned only theadaptation phase. The treatments arelisted as A = control, B = biological ne-maticide + Radopholus similis inocu-lum, C = R. similis inoculum and D =biological nematicide only.

Micropropagated plants ready forweaning were used. They were plantedin pots containing sterilized substrate


Figure 1. Effect of the biological nematicide for the protection of roots of micropropagated plantain.

0% p

aras

itis

m

A.ControlB. Biological nematicide + R. similisC. R. SimilisD. Biological nematicide

80

60

40

20

0

A B C D

Use of a new biological nematicide to protect the roots of plantain (Musa AAB) multiplied bymicropropagation

Biological control A nematophagous fungi

prepared from red soil, compost andbagasse. Ten days after planting, treat-ments B and D were inoculated withnematicide. After five days, each pot oftreatments B and C received a suspen-sion of 5 x 103 nematodes (R. similis)prepared by tissue culture on slices ofcarrot (Daucus carota). The percent-age of root infection, total weight, rootweight and the height of each tissueculture plant were measured 60 dayslater.

Results and discussionUnlike treatment C, treatments B and Ddid not display significant differenceswith regard to the control treatment Afor all the parameters evaluated (Fig-ure 1). This shows that when biologicalcontrol is present, R. similis does notcause serious damage to in vitro plantroots. These results confirm those re-ported for other biological nematicides(Jatala 1986, Davide1994) used to pro-tect the roots of other crops.

The plants to which the nematicideonly had been applied displayed greaterheight and weight than those of theother treatments; significant differ-ences were very small for the controland treatment B but high for treatmentC (Table 1).

The greater height and root weight ofthe in vitro plants on which the strainINIVIT 99-1 TPB was introduced may re-sult from the fact that this organismcontributes to the decomposition of or-ganic matter and releases nutrients intothe soil that can then be taken up by thein vitro plants, which is not the case inthe treatments not including microor-ganisms. It is also possible that the or-ganisms produce substances that stimu-

late plant growth, as occurs in other soilmicroorganisms (Davide 1994).

Conclusions and recommendationsThe use of biological nematicide (CepaINIVIT 99-1 TPB de Arthrobotrys sp.)effectively protects the roots of CEMSA3/4 plantain in vitro plants from attackby R. similis.

When it is used during the adaptationphase, INIVIT 99-1 TPB combined withcompost and bagasse increases theheight and weight of CEMSA 3/4 tissueculture plants.

Use of the new biological nematicideINIVIT 99–1 TPB is recommended forthe protection of the roots of plantainin vitro plants.

It is recommended that the efficacyof the nematicide should be tested onother banana and plantain clones sus-ceptible to plant nematode attacks.

It is recommended that the efficacyof the nematicide should be tested onother nematode species of great eco-nomic importance, such as Meloy-dogine spp., Pratylenchus coffeae andHelicotylenchus multicinctus. ■

ReferencesCortado R & R.G. Davide. 1968. Nematode-trapping

fungi in the Philippines (abstr). Phil. Phytopath.4: 4.

Davide R.G. 1994. Biological control of banana ne-matodes: development of BIOCON I (BIOACT)

and BIOCON II technologies. Pp. 139-146 in Ba-nana nematodes and weevil borers in Asia andthe Pacific. Proceedings of a conference-work-shop on nematodes and weevil borers affectingbananas in Asia and the Pacific. 18-22 April 1994,Serdang, Malaysia (R.V. Valmayor, R.G. Davide,J.M. Stanton, N.L. Treverrow and V.N. Roa, eds.).ASPNET Book Series 5. INIBAP/ASPNET, LosBaños, Philippines.

Duddington C.L. 1956. The friendly fungi. Faber andFaber Ltd., London. 168 pp.

Generalao L. & R.G. Davide. 1986. Biological controlof Radopholus similis with three ne-matophagous fungi. Phil. Phytopath. 22: 36-41.

Jatala P. 1986. Biological Control of Plant ParasiticNematodes. Ann. Rev. Phytopathol. 459-489.

Persson C & H.B. Jansson. 1997. Colonization of soilby nematophagous fungi. Tercer Seminario Cien-tífico Internacional sobre Sanidad Vegetal. Ciu-dad Habana. Resúmenes. 127 pp.

Stirling G.R. 1988. Biological Control of Plant Para-sitic Nematodes. Pp. 93-139 in Diseases of nema-todes. Vol. II. CRC Press Inc., Boca Raton,Florida.

The authors work at the Instituto de Investigacionesen Viandas Tropicales, INIVIT, Santo Domingo, VillaClara, Cuba, CP 53000, e-mail: [email protected].


Table 1. Effect of the different treatments on the root weight of plantain tissueculture.

Treatement Control A B C D

Root weight (g.) 5.9a 6.2a 1.3b 7.3aThe values followed by the same letter are significantly different at P < 0.05.

Edna A. Aguilar, David W. Turner andK. Sivasithamparam

Localized wilting in Cavendishplants in the Philippines (Stover1990) and Carnarvon, Western

Australia (Pegg et al. 1995) have beenassociated with sub-optimal conditions

such as waterlogging and poordrainage. These anecdotal reportshave not been investigated experimen-tally.

Excess water can be a problem in ba-nana plantations, particularly after aheavy rainfall or irrigation of heavysoil. Banana fields may suffer floodingor long-term waterlogging that may

damage the root system and contributeto the susceptibility of bananas toFusarium wilt (FW).

Waterlogging reduces O2 and in-creases CO2 and ethylene concentra-tion in soil (Ponnamperuma 1984). Thediffusivity of O2 in water is 1/10 000th ofits value in air; thus, dissolved O2 in thesoil solution is depleted in a few hoursor days due to consumption by plantroots and soil microorganisms (Drew1990). O2 is essential for respiration,the process by which aerobic organismsproduce energy in the form of ATP.Here, we review recent studies on theshort-term response of banana rootsand the FW pathogen (Fusarium oxys-porum f.sp. cubense (E.F. Smith) Sny-der and Hansen) to O2 deficiency andsuggest a role for these responses in the

Proposed mechanisms on howCavendish bananas arepredisposed to Fusarium wiltduring hypoxia

Effect of waterloggingPhysiology

predisposition of putative resistant ba-nana cultivars to FW.

Possible role of aerenchymaLysigenous air spaces (aerenchyma)have been reported in earlier studies ofbanana roots and in a number of culti-vars (Acquarone 1930, Riopel & Steeves1964, Aguilar et al . 1999). Theaerenchyma provides a continuous pathfor O2 diffusion from shoots to roots, in-creasing the flux of O2 along the cortex.We quantified the root porosity of dif-ferent banana cultivars and measuredinherent differences in ease of O2 move-ment along roots. The mature roots ofCavendish cultivars (AAA) have 10% ofthe volume as aerenchyma whileGoldfinger (AAAB) has 5% (Aguilar et

al. 1999). Hypoxia further increasedporosity and the thickness of the roots(Figure 1). When the physical resis-tance to internal gas diffusion was com-pared, the differences between the fourcultivars studied disappeared (Aguilaret al. 1998), suggesting that these rootswere equally adapted to stagnant condi-tions and potentially conduct gaseousO2 three to five times more easily thanaerated roots. O2 concentration in theroot tissues is sensitive to changes inthe outside O2 concentration. Even withcortical aerenchyma, the stele, wherethe pathogen initiates the disease, haslow O2 concentrations (1.3-2.6 kPa)even if the medium outside of the rootis fully aerated (21 kPa) (Aguilar et al.1998) (Figure 2). Hypoxia (4 kPa O2)

outside the roots induces stelar anoxiain excised banana roots (Aguilar 1998).Reducing the O2 concentration at theroot surface to about 18 kPa is esti-mated to already create an anoxic corein the stele. This finding has implica-tions for the development of Fusariumwilt because it is in the stele where thehost and pathogen interaction is criti-cal in disease development. When thestele is anoxic, the mobilization of thehost defense mechanisms in infectedroots may be slowed or stopped alto-gether, since most of these processesrequire energy.

If the FW pathogen could better tol-erate lower O2 concentrations, it wouldhave the impetus to colonize and besystemically distributed along the rootswhile the root suffers. In in vitro stud-ies, mycelial growth remained unim-paired even at 1% O2 but no growth oc-curred under anoxia (0% O2).Regeneration of growth following re-turn of aeration was observed (Aguilar1998). Germinating Foc conidia had lowhyphal density and frequently ceasedactivity and produced chlamydosporesor resting hyphae when O2 becomeslimiting (Figure 3). Our studies furthershowed that the pathogen could exploitthe presence of aerenchyma and the as-sociated higher concentrations of O2 itcontains (Aguilar 1998) (Figure 4).

Thus, the aerenchyma, although pro-viding an advantage for the host to sur-vive hypoxic conditions, could be the“Achilles heel” of some banana culti-vars that could otherwise resist Fusar-ium wilt. Aerenchyma appears to offeran alternative and favourable path forthe pathogen to invade the root longitu-dinally, outside of the vascular system.It is possible to envisage a scenariowhere the pathogen, using theaerenchyma as a base, occasionallygrows into the stele, to access nutri-ents, then transfers them via cytoplas-mic streaming back to the mycelium inthe aerenchyma where it obtains itsrespiratory requirement. This situationenables the pathogen to continue itsgrowth in the stele that by itself wouldbe an adverse environment. It is likelythat when conditions in the stele are in-hospitable for the pathogen, Foc couldresort to a latent phase. The process in-volving the passage of the pathogenthrough the aerenchyma could con-tribute to rapid invasion of the corm(Aguilar 1998).

Role of reduced root elongationand root tip death under anoxiaAnoxia (0% O2) in the root mediumstopped root elongation within 30 min-utes. Re-aeration after 4 h of anoxia re-stored elongation rate to only 50% of


Figure 2. Oxygen profile of banana root (28 mm from the apex) measured by a microelectrode instreaming solution.

Figure 1. Aerenchyma development in roots of cv. Williams grown in stagnant or aerated nutrientmedium. Roots were about 200 mm long. The sections were taken 50 mm and 100 mm from the roottip. Scale is 0.1 mm.

Roots emerged in stagnantmedium (50mm from tip)

Roots emerged in aerated medium(50mm from tip)

Roots emerged in stagnantmedium (100mm from tip)

Roots emerged in aerated medium(100mm from tip)

Oxy

gen

e d

iffu

sio

n c

urr

ent

(pA

) Oxyg

en co

ncen

tration

(kPa)

boundary layer

non-porous cotex

porous cortex

stele

continuously aerated roots. Anoxia formore than 6 h killed the root tips(Aguilar 1998) (Figure 5). Reduced rootgrowth can favour infection by increas-ing the time of exposure of susceptibleparts of the root to the inoculum, whiledeath of root tips would give thepathogen an open infection route withdirect access to the stele. This suggeststhat even temporary flooding could fa-cilitate the entry and perhaps patho-genic activity of the pathogen into theroot without it being subject to the nor-mal host resistance mechanisms of un-affected tissue. Fusaria appear to havethe capacity to be a facultativenecrotroph capable of being an endo-phyte in susceptible and resistanthosts.

Several, short bursts of anoxia, eachof which was not severe enough to killthe root tips, enabled the roots to sur-vive and elongate further but at a re-duced rate (Aguilar et al. 1998). Thissuggests the ability of roots to acclima-tize to hypoxia. Hypoxic pretreatmentimproves tolerance to anoxia in maize(Gibbs et al. 1998).

Role of peroxidase (PER) andphenylalanine ammonia lyase(PAL) enzymesPER and PAL are key enzymes impli-cated in induced resistance. The pro-duction of peroxidase (PER) is corre-lated with increased lignification anddisease resistance in host-pathogen sys-tems such as cabbage and Fusariumoxysporum f.sp. conglutinans (Heite-fuss et al. 1960), potato and Phy-topthora infestans (Friend et al. 1973),diploid banana (Musa acuminataColla) and Foc (Morpugo et al. 1994).PAL activity is correlated with resis-tance in crops, such as cowpea, to thepathogen Phytophthora vignae (Ralton

et al. 1988) and soybean toP. megasperma f.sp. glycinea (Bhat-tacharya and Ward 1988).

We investigated the effects of Foc in-fection and hypoxia on the activities ofPER and PAL in the roots of cultivarsknown to be resistant or susceptible toFoc (Aguilar et al. 2000).

Hypoxia stimulated PAL and PER ac-tivity. It is not known whether the in-creased activities of these enzymes, re-sulting from hypoxic stress, could offersome protection to the host. Foc infec-tion increased PER activity. When thepathogen and hypoxia were combined,the differences in rapidity and degreeof increase in PAL and PER activitiesappear to be associated with resistanceto FW, particularly with the breakdownin resistance of Williams (a Cavendishcultivar). Goldfinger, known to be moreresistant to FW, responded with higherand more sustained PER and PAL activ-

ities compared with either cv. Williamsor cv. Gros Michel (Figures 6 and 7).This quantitative difference could be afactor that contributes to Williams suc-cumbing to FW under waterlogging(Aguilar et al. 2000). There are someexciting issues here that need furtherinvestigation. While hypoxic treatmentmight be a way to stimulate the root’sdefence mechanism, it has to be at alevel, duration and timing that wouldenhance PER and PAL activities with-out causing irreparable damage to rootfunctions. Genetic markers may befound among banana cultivars for theseenzymes which could be used in build-ing up quantitative resistance in ba-nanas to Fusarium wilt.

The site of synthesis and enzyme ac-tivity in the root is critical in determin-ing its importance for Fusarium wilt re-sistance. To be effective, increasedenzyme activity should be concentratedin, or around, the vascular systemwhere the active host defence mecha-nisms operate and in tissues adjacentto the root tip which could be sites ofinfection, particularly in the event ofroot tip death. Phenol metabolism is anoxidation process and hypoxia shouldhave rendered parts of the stele anoxicwhile the cortex will be relatively moreaerated. It is possible that PAL is syn-thesized in the more aerated parts ofthe root but whether it can be active inthe stele where it is much needed is yetto be established (Aguilar et al. 2000).

The PAL and PER enzyme activitiesdeclined upon re-aeration, whereas thepathogen (which forms resting sporesunder hypoxia) easily reverts to nor-mal mycelial growth upon re-aeration.Thus, Foc’s renewed activity withinhours of re-aeration should bematched with sustained enzyme activ-


Figure 4. Hyphal growth of Fusarium wilt pathogen in cortical aerenchyma of banana roots.

hyp

hal

den

sity

(m

m/m

m2 )

Diffuse path length (mm)

40

35

30

25

20

15

10

5

00 2 4 6 8 10 12

Figure 3. Effect of increasing diffusive path length (mm) of O2 on hyphal density (mm/mm2) ofFusarium oxysporum f. sp. cubense (Foc) 24 h after inoculation.

ity in a host resistant interaction. Thebest option for the host to incur resis-tance would be to sufficiently increaseenzyme activities during hypoxia tocontain the then inactive pathogen be-fore re-aeration. Post-anoxic injurywhen the stress becomes too severe,could deprive the host of its ability forcontinued resistance (Aguilar et al.2000).

ConclusionIt is the physiological state of the hostupon re-aeration that will determinethe outcome of host-pathogen interac-tion under oxygen deficiency. Irrepara-ble damage to root function wouldsurely favour the pathogen, and hence,disease development follows or may

even be enhanced. If the root acclima-tizes and elicits timely and sufficientdefence reactions during hypoxia, thenit could gain advantage over thepathogen. When the next stress occurs,its duration and severity will most likelydetermine the ensuing host-pathogendynamics (Aguilar 1998). ■

ReferencesAcquarone P. 1930. The roots of Musa sapientum L.

Rep. No. 26. United Fruit Co., Research Dept.Boston, Mass.

Aguilar E.A. 1998. Responses of banana roots to oxy-gen deficiency and implications for Fusariumwilt infection. PhD Thesis, The University of Wes-tern Australia. 148 pp.

Aguilar E.A., D.W. Turner, D.J. Gibbs, W. Armstrong& K. Sivasithamparam. 1998. Response of banana

(Musa sp.) roots to oxygen deficiency and its im-plications for Fusarium Wilt. Acta Horticulturae490: 223-228.

Aguilar E.A., D.W. Turner & K. Sivasithamparam.1999. Aerenchyma formation in roots of four ba-nana (Musa spp.) cultivars. Scientia Horticultu-rae 80: 52-72.

Aguilar E.A., D.W. Turner & K. Sivasithamparam.2000. Fusarium oxysporum f.sp. cubense inocu-lation and hypoxia alter peroxidase and phenyla-lanine ammonia lyase enzyme activities in nodalroots of banana cultivars (Musa sp.) differing intheir susceptibility to Fusarium wilt. AustralianJournal of Botany 48: 589-596.

Bhattacharya M.K. & E.W.B. Ward. 1988. Phenylala-nine ammonia-lyase activity in soybean hypoco-tyls and leaves following infection with Phytoph-thora megasperma f. sp. glycinea. CanadianJournal of Botany 66: 18-23.

Drew M.C. 1990. Sensing soil oxygen. Plant, Cell andEnvironment 13: 681-693.

Friend J., S.B. Reynolds & M.A. Aveyard. 1973. Phe-nylalanine ammonia-lyase, chlorogenic acid andlignin in potato tuber tissue inoculated with Phy-tophthora infestans. Physiological Plant Patho-logy 3: 495-507.

Gibbs J., D. W. Turner, W. Armstrong, M.J. Darwent& H. Greenway. 1998. Response to oxygen defi-ciency in primary roots of maize. 1. Developmentof oxygen deficiency in the stele reduces radialsolute transport to the xylem. Australian Journalof Plant Physiology 25: 745-758.

Heitefuss R., M.A. Stahmann & J.C. Walker. 1960.Oxidative enzymes in cabbage infected by Fusa-rium oxysporum f. conglutinans. Phytopatho-logy 50: 370-375.

Morpugo R.S., V. Lopato & F.J. Novak. 1994. Selec-tion parameters for resistance to Fusarium oxy-sporum f.sp. cubense race 1 and race 4 on di-


Figure 6. Effect of inoculation by Fusarium oxysporum f. sp.cubense (Foc) and/or hypoxia on phenylalanine ammonia-lyase(PAL) enzyme activity in roots of banana cvs a) Williams, b)Goldfinger, c) Gros Michel and d) Sugar. Treatments were: noFoc, continuously aerated (NFA); Foc-inoculated, continuouslyaerated (FA); Foc-inoculated, continuously hypoxic (FHH); noFoc, continuously hypoxic (NFHH); no Foc, hypoxic for 48 h, thenre-aerated (NFHA); and Foc-inoculated, hypoxic for 48 hours,then re-aerated (FHA). Vertical bars along line plots arestandard errors where they are larger than the symbols. Verticallines outside of plots are measures of significant meandifferences at p = 0.05 using Duncan’s Multiple Range Test(DMRT). Top to first division is for comparison of adjacentpoints, while from top to the bottom division is for comparisonof highest to lowest points.

a)Williams

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Figure 7. Effect of inoculation by Fusarium oxysporum f. sp. cubense (Foc)and hypoxia on peroxidase (PER) enzyme activity in roots of banana cvs a)Williams, b) Goldfinger, c) Gros Michel and d) Sugar. Treatments were: noFoc, continuously aerated (NFA); Foc-inoculated, continuously aerated (FA);Foc-inoculated, continuously hypoxic (FHH); no Foc, continuously hypoxic(NFHH); no Foc, hypoxic for 48 hours, then re-aerated (NFHA); and Foc-inoculated, hypoxic for 48 hours, then re-aerated (FHA). Vertical bars alongline plots are standard errors where they are larger than the symbols.Vertical lines outside of plots are measures of significant mean differencesat p = 0.05 using Duncan’s Multiple Range Test (DMRT). From top to firstdivision is for comparison of adjacent points, while from the top to thebottom division is for comparison of highest to lowest points. Horizontalline HH indicates the duration of the continuous hypoxic treatment (120 htotal) and HA indicates the duration of the short-term hypoxia (48 h) andwhen re-aeration commenced (72 h).

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Figure 5. Root elongation of banana cv. Williams in aerated nutrient solution (control) and afterimposition of 2,4 and 6.5 hours of anoxia.

0

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ploid banana (Musa acuminata Colla). Euphy-tica 75: 121-129.

Pegg K.G., R.G. Shivas, N.Y. Moore & S. Bentley.1995. Characterisation of a unique population ofFusarium oxysporum f.sp. cubense causing Fu-sarium wilt in Cavendish bananas at Carnarvon,Western Australia. Australian Journal of Agricul-tural Research 46: 167-178.

Ponnamperuma F.N. 1984. Effects of flooding onsoils. Pp. 10-46 in Flooding and Plant Growth(T.T. Kozlowski, ed.). Academic Press, Inc., Flo-rida.

Ralton J.E., B.J. Howlett, A.E. Clarke, J.A.G. Irwin &B. Imrie. 1988. Interaction of cowpea with Phy-tophthora vignae: inheritance of resistance andproduction of phenylalanine ammonia-lyase as aresistance response. Physiological and MolecularPlant Pathology 32: 89-103.

Riopel J.L. & T.A. Steeves. 1964. Studies on theroots of Musa acuminata cv. Gros Michel: theanatomy and development of main roots. Annalsof Botany 28: 475-494.

Stover R.H. 1990. Fusarium wilt of banana: somehistory and current status of the disease. Pp. 1-18in First International Conference on FusarialWilt of Banana (R.C. Ploetz, ed.). American Phy-topathological Society Press, St. Paul, Minn.

Edna A. Aguilar works at the Farming Systems andSoil Resources Institute, College of Agriculture, Uni-versity of the Philippines at Los Baños, College, La-guna 4031, Philippines, David W. Turner works inPlant Sciences, and K. Sivasithamparam in SoilScience and Plant Nutrition at the Faculty of Agricul-ture, The University of Western Australia, Nedlands,WA 6907, Australia.


Josué Francisco da Silva Junior, ZiltonJosé Maciel Cordeiro and Arlene

Maria Gomes Oliveira

Panama disease or Fusarium wilt ofbanana caused by the fungusFusarium oxysporum f. sp.

cubense (Foc) is one of the most seri-ous problems in banana production asit causes serious damage in outbreakzones. The decisive role played by thegenotype of banana cultivars in the ex-pression of their resistance or suscepti-bility to the disease is well known. How-ever, it is also considered that theintensity of Panama disease is more orless directly related to edaphic factorsand plant nutrition and that these fea-tures may affect resistance mechanismssuch as gel (gum) formation and tylosis(Stover 1962, Borges Perez et al. 1983,Beckman 1990).

In the Canary Islands, Alvarez et al.(1981), Gutierrez Jerez et al. (1983),Borges Perez et al. (1983) and TrujilloJacinto del Castillo et al. (1983) per-formed soil observations in healthy andinfected zones and concluded that thepH, the organic matter content (OM),levels of calcium (Ca), magnesium(Mg) and zinc (Zn) and Ca:Mg andK:Mg ratios were closely correlatedwith the appearance of the disease. InTaiwan, Tu and Cheng (1982), Hwang(1985), Sun and Huang (1985) and Suet al. (1986) obtained promising resultswhen they undertook tests with a viewto controlling Panama disease bymeans of suppressive and conducivesoils and the addition of various organicor inorganic compounds to soils wherethere had been severe attacks of thedisease. Observations in Bahia State inBrazil showed that the organic mattercontent was higher in healthy soil zones(EMBRAPA 1987).

In Brazil again, Malburg et al. (1984)reported that low pH values and Ca, Mgand Zn levels in soils in Santa CatarinaState planted with ‘Enxerto’ (‘PrataAnã’ AAB) and ‘Branca’ (AAB) bananaswere related to a high wilt level. Obser-vations in Bahia and Espirito Santoshowed that in infected zones the pHand Ca, Mg and Zn levels were lowwhereas K:Ca and K:Mg ratios werehigh (EMBRAPA 1987, EMCAPA 1988).

In Tenerife, Borges Perez et al. (1991)observed that Zn fertilization for threeyears significantly reduced the inci-dence in the field of Panama disease in‘Dwarf Cavendish’ banana.

In the light of these resultsis, thework presented here was aimed at eval-uating the effect of chemical character-istics of soils such as the organic mattercontent, pH, level and Ca, Mg and Znlevels on the incidence and intensity ofPanama disease in ‘Prata Anã’ banana(AAB).

Material and methodsThe trial was performed on land belong-ing to the Centro Nacional de Pesquisade Mandioca e Fruticultura Tropical(CNPMF), Empresa Brasileira dePesquisa Agropecuária (EMBRAPA), atCruz das Almas, Bahia State, Brazil.Holes with a volume of 0.38 m3 (0.70 min diameter and 0.30 m deep) linedwith polyethylene were filled with ei-ther yellow latosol with cohesion Tb,and medium to clayey texture or withorganic soil collected at a depth of 0 to30 cm. The original chemical character-istics of the soils used are shown inTable 1. Corms weighing about 2 kg ofthe cultivar ‘Prata Anã’ (AAB), consid-ered to be susceptible to Panama dis-ease (Cordeiro et al. 1991), wereplanted.

A fully random statistical protocolwas used with 10 treatments and 10repetitions, with each plant represent-ing an experimental plot. The followingtreatments were applied to evaluate theeffect of Ca alone or in combinationwith Mg, pH, OM or soil sterilizationand the addition of Zn: 0) Organic soil + liming1) Sterilized organic soil + liming2) Sterilized inorganic soil + liming3) Inorganic soil with no liming4) Inorganic soil + ZnSO4 + liming5) Inorganic soil + liming6) Inorganic soil + liming with CaCO3

(pH approximately 7.5)7)Inorganic soil + liming with

CaCO3.MgCO3 (pH approximately 7.5)8) Inorganic soil + liming with MgO

(pH approximately 7.5)9) Inorganic soil + CaSO4.2H2OInorganic and organic soils were steril-ized by fumigation with methylene bro-mide at 340.55 cm3 per m3 soil.

Soil chemical parameters inrelation to the incidence andintensity of Panama disease

Diseases Influence of soil composition

Dolimitic limestone (total relativeneutralization capacity 99%) was usedin treatments 1, 2, 3, 5 and 6 to achieveCa+Mg contents of 40 mmolc/dm3 inconformity with the indications pro-vided by the soil analysis (Comissão Es-tadual de Fertilidade do Solo 1989).This means that 3.13 t/ha lime wasadded in treatments 1 and 2 and 2.93t/ha to treatments 3, 5 and 6. Treatment4 was the control since it does not in-clude any liming.

In treatments 7, 8 and 9, the Ca andMg sources (calcitic lime, dolomiticlime and magnesium oxide respec-tively) raised the soil pH to approxi-mately 7.5. In conformity with the incu-bation method recommendations, 9.48t/ha calcitic lime was added in treat-ment 7, while 7.46 t/ha dolomitic limewas added in treatment 8, and 3.23 t/hamagnesium oxide in treatment 9.

In treatment 10, application of 13.70t/ha agricultural plaster correspondedto 277.12 g Ca per hole, i.e. the sameamount Ca as applied in treatment 7 inthe form of CaCO3.

Zinc sulphate at 19.05 g/hole, theequivalent of 4.0 g Zn/plant was addedtwo months after sowing in treatment 5at the same time as the first nitrogenfertilization.

The plants were fertilized with NPKat 100 kg N/ha, 40 kg P2O5/ha and 450kg K2O/ha, provided by ammonium sul-phate, single superphosphate andpotassium chloride respectively.

Soils were analyzed using themethodology of the Serviço Nacionalde Levantamento e Conservação deSolos - SNLCS (EMBRAPA 1979). Sam-ples were taken during the followingphases of the experiment: before theholes were dug, at planting (twomonths after chemical correction) andafter 11 months of plant growth.

The plantlets were inoculated fourmonths after planting with 6.0 ml sus-

pension of Foc spores, corresponding to8.3 x 107 conidia/hole or 700 conidia/gsoil. The inoculum was placed in 100gmaize flour-sand mixture. Inoculationwas performed by digging furrows 10cm deep around each plant, spreadingthe inoculum and then refilling imme-diately (EMBRAPA 1991).

The final evaluation of infection wasperformed seven months after inocula-tion by pulling out 11-month-old plantsto observe the degree of rhizome infec-tion in a series of cross sections run-ning from the base to the apex andrecording scores of 0 to 6 on the scaleproposed by Cordeiro et al. (1993):0. Rhizome totally undamaged1. Isolated points of infection2. Infection covering more than 1/3 of

the stele cross section3. Infection covering 1/3 to 2/3 of the

stele cross section4. More than 2/3 of the stele cross sec-

tion infected5. Overall infection6. A plant displaying external symptoms

and/or symptoms visible on the pseu-dostem.

Analysis was performed from the dataobtained by applying Tukey’s test (P <0.05) to compare the averages of thedifferent treatments. Pearce’s correla-tion coefficients were also calculated.

Results and discussion

The effect of organic matterThe high OM content of the organic soilin comparison with that of the inor-ganic soil affects the levels of intensity

of the disease. Indeed, treatments 1and 2 display lower indices of infectionthan those of the other treatments (Fig-ure 1). The strong correlation (r = 0.61)between the average score for Foc in-fection and the organic matter content(Table 2) confirms the positive effect ofOM on the control of Foc, with a 1% de-gree of significance. In addition, withno sterilization (treatment 1), the useof organic soil results in significant dif-ferences compared to the control(treatment 4) in Tukey’s test (5%).

These results show that the damageto plants caused by the pathogen is in-significant, implying that this soil maypossess a suppressive character that re-mains as long as the conditions deter-mining it are maintained. According toHornby (1983), the majority of themechanisms proposed for explainingthe suppression of the disease on thistype of soil have not been proved. It isassumed that abiotic factors such as cli-mate, soil chemical characteristics(acidity, type of clay) and physical char-acteristics (moisture) act in synergywith the biotic factors.

Among biotic factors, it is supposedthat the phenomenon of antagonism be-tween the original soil microbiosphereand the pathogen causes the reductionof infection. The phenomenon is verycommon in soils that are very rich inOM and is important for the microbio-logical equilibrium of the soil and thebiological control of pathogenic organ-isms (Clark 1965, Siqueira and Franco1988). The high percentage of OM isgenerally related to a high microbialpopulation (Warcup 1965) and in-creases the soil fungistasis effect, mak-ing it difficult for a newly introducedmicroorganism to become established.This results in reduction or control ofthe disease.

There are no significant differencesbetween infection levels with regard tothe sterilization or not of organic soils(treatments 1 and 2) and mineral soils(treatments 3 and 6) (Figure 1). Ac-cording to Hemwall (1960), soils with ahigh OM content are relatively difficultto fumigate. Later, Kreutzer (1965)pointed out that OM can also protectsoil microorganisms from the effect offumigants.

In addition, it is known that whensoils are sterilized, as in this experi-ment, the original microbiosphere recov-


Table 1. Initial chemical characteristics of the yellow latosol and the organic soil(from a depth of 0-30 cm) used in the trial at Cruz das Almas, BA, Brazil.

Characteristics Yellow latosol Organic soil

pH - H2O 4.80 4.70

P (mg/dm3) 0.90 27.50

K (mmolc/dm3) 0.50 0.90

Ca (mmolc/dm3) 6.50 6.50

Mg (mmolc/dm3) 4.50 2.50

Al (mmolc/dm3) 1.00 1.20

Na (mmolc/dm3) 0.50 0.90

H + Al (mmolc/dm3) 54.00 188.00

CTC (mmolc/dm3) 66.00 198.00

Organic matter (g/dm3) 21.00 173.00

Mn (mg/dm3) 3.94 1.10

Fe (mg/dm3) 89.05 27.49

Zn (mg/dm3) 3.50 3.17

Cu (mg/dm3) 0.31 0.71

Table 2. Coefficients of correlation between organic matter, pH and Foc infectionscores.

Variables pH Organic matter

Organic matter -0.22*

Infection score 0.43** -0.61*** Significant at 0.05 probability.

** Significant at 0.01 probability.

ers rapidly because methyl bromide doesnot have any residual effects (Kreutzer1965, Vanachter 1979). Some microor-ganisms that possess survival structuresand resist fumigation—in particular cer-tain fungi—may be capable of initiatingrepopulation (Kreutzer 1965).

The effect of pH, calcium and magnesiumThe application of large quantities ofCa alone, using agricultural plaster,without changing the initial pH of inor-ganic soil (treatment 10), did not havea positive effect on the control of thedisease (Figure 1). This is in conformitywith the experiments performed byKnudson from 1923 to 1927 (Stover1962), in which the Ca compounds useddid not modify the soil pH.

It is observed that the high soil pH re-sults in an infection rate that is alsohigh. The liming performed to raise thepH to approximately 7.5 in treatments7, 8 and 9 using large quantities of Ca,Ca+Mg and Mg respectively did nothave a positive effect with regard tocontrol of Panama disease, since the in-fection levels observed were higherthan that of the control (Figure 1).

Similar results were obtained in someproduction regions in the world (Stover1962, Blesa Rodríguez and FernandezCaldas 1973, García 1977) where soilswith high pH and high Ca and Mg con-

tents were affected by the disease.There have even been cases, as in Tai-wan (Hwang 1985), in which the high-est infection indexes were recorded in

zones where liming was performed(zones with a pH higher than 7.0). How-ever, the positive effect on Panama dis-ease of a high pH combined with Ca andMg has been widely described in the lit-erature, with the observations and testsperformed by Knudson (1923-1927),Volk (1930 a, b), Volk and Gallatin(1930), Wardlaw (1935), quoted byStover (1962), Scarseth (1945), Rish-beth (1957), Stover and Malo (1972),Alvarez et al. (1981), Malburg et al.(1984) and EMCAPA (1988).

In treatments 7, 8 and 9, the largedoses of Ca and Mg applied singly or to-gether, combined with a high pH proba-bly caused an imbalance in the inor-ganic soil, influencing not only itschemical characteristics but also itsoriginal microbiosphere, in which mi-croorganisms that are important com-petition for the pathogen were thuseliminated. This imbalance, combinedwith the susceptibility of the cultivarused, may have contributed to higherlevels of infection in the plants.

In treatment 4 (Figure 1), the bal-ance of soil characteristics was almostunchanged and this may be one of thereasons for the minor incidence of thedisease. In addition to this, the poorsoil fertility conditions in this treat-ment may have caused less root growthresulting in a smaller infection indexbecause the pathogen penetrates theplants via the secondary and tertiaryroots (Stover 1962). The more devel-oped the root system, the greater thechances of new infections.

The effect of zincThere were no significant differences ininfection levels when zinc was added toinorganic soil (treatment 5) and com-pared with treatments 4 (control) and 6(treatment without Zn but with liming)(Figure 1). Because of its susceptiblebehaviour, the cultivar ‘Prata Anã’ isprobably not effective in time and spacein the development of effective resis-tance mechanisms (Beckman et al.1962, Borges Perez et al. 1983, Beck-man 1990). Or perhaps it might havebeen necessary to add larger quantitiesof this nutrient, as is done on ‘DwarfCavendish’ in the Canary Islands(Borges Perez et al. 1991). A third hy-pothesis could be that Zn has little orno effect on the control of Panama dis-ease in contrast with suppositions.

Conclusions• Organic soil was found to be a sup-

pressive substrate for the develop-ment of Panama disease in ‘PrataAnã’ banana.

• Liming performed to raise the soil pHto approximately 7.5 using Ca and Mg

and the addition of large quantities ofCa alone without modifying the soilpH have no positive effect on the con-trol of Panama disease.

AcknowledgementsThe authors thank Ana Lucia Borgesand Aristóteles Pires de Matos, re-searchers at Embrapa Mandioca eFruticultura, for their suggestions. ■

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Figure 1. Evaluation de l’infection par le Foc surle bananier “Prata Aña” soumis à différentstraitements. Cruz das Almas, Brésil, 1992-1993.(Des moyennes suivies par la même lettre nediffèrent pas significativement entre elles, auniveau de 5 % par la preuve de Tukey).

Traitments1. organis soil +liming2. sterilized organic soil + liming3. sterilized inorganic soil + liming4. inorganic with no liming5. inorganic soil + ZnSO4 + liming6. inorganic soil + liming7. inorganic soil + liming with CaCO3. (pH = 7.5)8. inorganic soil + liming with CaCO3. MgCO3 (pH = 7.5)9. inorganic soil + liming with MgO(pH = 7.5)10. inorganic soil + CaSO4.2H2O

d cd

a

bc

abab

aa

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ab

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ion

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2,73,9

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Vanachter A. 1979. Fumigation against fungi. Pp.163-183 in Soil disinfestation (D. Mulder, ed.).Elsevier, Amsterdam.

Warcup J.H. 1965. Growth and reproduction of soilmicrorganisms in relation to substrate. Pp. 509-518 in Ecology of soil-borne plant pathogens:prelude to biological control (K.F. Baker & W.C.Snyder, eds.). John Murray, London, UK.

Josué Francisco da Silva Junior is a researcher atEmpresa Pernambucana de Pesquisa Agropecuária(IPA), Caixa Postal 1022, CEP 50761-000, Recife, PE,Brazil. E-mail: [email protected]; Zilton José MacielCordeiro and Arlene Maria Gomes Oliveira are re-searchers at Embrapa Mandioca e Fruticultura, CaixaPostal 007, 44380-000, Cruz das Almas, BA, Brazil. E-mail: [email protected]; [email protected].


Claudia Milena Cardona Torres,Gustavo Adolfo Yepes González and

Jairo Castaño Zapata

The Musa industry (banana andplantain) is one of the farming ac-tivities with the greatest social im-

pact in the regions where it is prac-tised. Black Sigatoka disease (causedby Mycosphaerella fijiensis) is themain phytosanitary threat to these foodand income resources (Jacome 1998).Yellow Sigatoka disease (caused by M.musicola) is gradually being replacedby black Sigatoka in large cultivatedareas. The latter disease can cause adecrease in harvest of up to 50 percent,affecting growers’ incomes considerably(Burt et al. 1997). According to the

most recent epidemiological observa-tions, black Sigatoka can affect cropsfrom sea level to an elevation of 1940 m.It was believed possible that only smalloutbreaks would occur higher than1000 m but observations in Colombiahave shown that this is not the case(Aguirre et al. 1998).

Chemical control and breeding resis-tant plants are still the only strategiesfor controlling black Sigatoka. Cultivarswith some degree of genetic tolerancemight not seem to be a priority for largegrowers whereas for small farmers re-sistant or tolerant clones are the con-trol method best-suited to the technicaltraining and socioeconomic context ofthe crop (Wesseling et al. 1996, quotedby Riveros and Lepoivre 1998).

The main aim of the research workpresented here was to evaluate the ef-

fect of mutagenesis caused by 60Co onthe type of resistance or tolerance thatcould be developed by the cultivar ‘Do-minico Hartón’ with regard to blackSigatoka (M. fijiensis) or yellow Siga-toka (M. musicola).

Material and methodsThe project was set up at the Campoale-gre plantation on the La Ceiba track onthe Manizales (Caldas) – Mariquitaroad 7 km from Fresno in Tolima de-partment at an elevation of 1250 m,with an average temperature of 18 to25°C, relative humidity of 65 to 100%and annual precipitation of 1800 mm.The land is sloping and black and yel-low Sigatoka had been detected. Plant-ing was performed with 1600 ‘DominicoHartón’ tissue culture plants that hadbeen subjected to 60Co at a dose of 25

Intensity of black Sigatoka (Mycosphaerella fijiensisMorelet) and yellow Sigatoka (Mycosphaerellamusicola Leach) in Musa AAB cv. ‘Dominico Hartón’subjected to irradiation by 60Co

Improvement Mutation breeding using 60Co

Gy at INEA (Bogotá), multiplied in theAgricultural Faculty tissue culture labo-ratory, weaned at Granja Montelindo,owned by Universidad de Caldas, andfinally transported to the planting loca-tion. The plants produced by mutagene-sis were surrounded by non-irradiatedplants of the same clone (controls) toobtain greater inoculum pressure. Eval-uations were performed each weekfrom 24 May 1998 to 10 April 1999 on 58cloned plant and 5 control plants. Eachcloned plant was considered as an ex-perimental unit for the following vari-able parameters:

Host parameters: number of func-tional leaves on the pseudostem, date ofshooting of the inflorescence andbunch weight (kg).

Disease parameters: youngest leafspotted (YLS), taking into considera-tion stage 4 spots for yellow Sigatokaand stage 5 spots for black Sigatoka, in-tensity of disease attacks according toStover’s scale modified by Gauhl (1984)and the infection index of the diseases.Intensity scale of yellow and black Siga-toka diseases: 0. Healthy leaf, no symptoms 1. Up to 5% of leaf affected2. 6 to 15% of leaf affected3. 16 to 33% of leaf affected4. 34 to 50% of leaf affected5. 51 to 100% of leaf affected

Intensity scale: calculated using theformula of Townsend and Heubergueraccording to Unterstenhuefer (1963),quoted by Orjeda et al. (1998):

in which:IS = intensityn = number of leaves at each stageb = stageN = number of stages used in the scaleT = total number of leaves evaluated.

Index of the youngest spotted leaf:calculated using the following formula:

in which: IYLS = index of the youngest leaf

spottedYLS = youngest leaf spotted at the mo-

ment of the evaluationT= total number of leaves evaluated.

Meteorological parameters: tempera-ture (maximum, minimum and average),relative humidity and precipitation.

The data were analyzed according toa fully randomized design in function oftime, and processed using the SAS(System Analysis Statistical) pro-gramme, through estimations obtained

by regressions, confidence intervals,analyses of variance and descriptiveprocedures.

Results and discussion The climatic conditions in the studyzone consisted of an average tempera-ture of 21.5°C, relative humidity of 81%and cumulated precipitation of 340.5mm. Analysis of the climatic conditionsin detail and in relation to the develop-ment of the diseases showed that pre-cipitation is a determinant parameterfor the appearance of infection. Tem-perature and relative humidity duringthe study enhanced the development ofthe epidemic as temperatures of 20 to35°C enable ascospore and conidiumgermination; this is maximized at tem-peratures of the order of 25 to 28°Cwith high relative humidity and wetleaves (Jacome and Schuh 1992). Thediseases display seasonal dynamics de-termined by variations in temperatureand precipitation throughout the year,because the reproductive structures de-velop by cross-inoculation, a processenhanced by the presence of moistureon the leaves (Mourichon and Zapater1990).

The development curve of the dis-eases displays two peaks on the 297th

and 477th day after planting. Thesedates coincide with periods of strongprecipitation (Figure 1). The crop wasstill in the vegetative phase 297 daysafter planting, but very close to theflowering period, hence the importanceof keeping a large number of leaves. In-deed, as reported by Ortiz and Vuyl-steke (1994), quoted by Craenen(1998), a minimum of eight functionalleaves are required throughout thecycle to achieve a good yield. In addi-tion, plants with fewer than eight non-spotted leaves before flowering arelisted as being susceptible to blackSigatoka disease. The clone plants wereat the bunch development stage 477days after planting. This is why a betterbunch weight was not attained at theend of the experiment, because in 80%of the specimens evaluated theyoungest leaf spotted (YLS) was in posi-tion 1 with high disease intensity in-dexes of up to 100%.

Only 45% of the clones evaluated, in-cluding the controls, reached the flowershooting stage with more than eightfunctional leaves. Among them, clones4, 17, 18, 21, 38 and 44 stood out as hav-ing the greatest number of functionalleaves (11); the others completed theircycle with fewer than 11 leaves becausemost were completely infected by thediseases.

At the beginning of the experiment,the highest intensity levels were ob-


Figure 1. Incidence of climatic conditions on the development of black and yellow Sigatoka (May 1998 - April 1999).

Prec

ipit

atio

n (

mm

)Se

veri

ty

Tem

per

atu

re (

°C)

and

rel

ativ

eH

um

idit

y (%

)

0

50

100

150

200

250

300

350

400

100

80

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20

0207 237 267 297 327 357 387 417 447 477 507

010

20

30

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60

7080

90

Days after planting

Maximum severity Medium temperature Relative humidity

served on the lower leaves of the plants.As time passed, the disease spread tothe upper leaves, showing that diseaseintensity is related directly to the leafemission.

When the inflorescence appearedsome 342 days after planting, the lowerleaves, and especially those in positions11, 12, 13 and 14, displayed higher dis-ease indexes. This is the result of thesize of the plants and the larger leafarea, with greater risk of reception ofinoculum for future infection. At theend of the study, 50% of the clones hadfewer than four functional leaves. Atharvesting, individuals 8, 15, 16, 41 andthe controls had only one leaf and thiswas at grade 5 disease intensity (> 50%);this intensity was closely linked to theclimatic conditions during the period.

No promising clones were detectedin general with regard to resistance toyellow or black Sigatoka. Informationconcerning the intensity of the dis-eases for six clonal plants with the low-est indexes for leaves 6, 7, 8 and 9 areshown in Table 1. The final intensity isover 40% for the irradiated clones andthere is no significant difference com-pared to the control. Among these indi-

viduals, clone 57 displayed the greatestfinal disease intensity at 70.48% for theleaf 6. Most of the clones displayedhigh disease intensity indexes aftershooting of the inflorescence. Amongthem, clones 9 and 57 displayed maxi-mum intensity (100%) on leaf 9 and av-erage intensity increased on the oldestleaves 8 and 9. In agreement with thefindings of Belalcázar et al. (1994),analysis of the percentages of maxi-mum disease intensity clearly showswhether the clones are resistant

or susceptible, especially by evaluationof leaf 9.

The clones were therefore classifiedas ‘highly susceptible’ in this work.

Both the intensity index and that ofthe youngest spotted leaf behaved in avery heterogeneous manner during theinflorescence shooting period (342-432days after planting), when the greatestvariation was observed in relation totime. From then onwards, the plantsstopped leaf emission and began theprocess of translocation of nutrients tothe inflorescence. As a result, theleaves were weakened and becamemore susceptible to the diseases. Thiswas augmented by climatic conditions(temperature 21°C, relative humidity75% and cumulated precipitation 100mm) encouraging the development ofthe diseases and allowing them tospread over the entire leaf surface ofthe plants. All this, together with thefact that the optimum number of leavesneeded for a satisfactory bunch (mini-mum 8 leaves) was not conserved, re-sulted in bunches with strongly reducedquality and weight (average 12 kg)(Table 2).

The behaviour of the clones most re-sistant to Sigatoka diseases and its ef-fect on the production parameter canbe seen in the same table. Some differ-ences between the epidemiological pa-rameters were observed in these indi-viduals and were to have repercussionson crop yield. As a whole, there were nosignificant differences between theseand the youngest leaf spotted (YLS)variable. Individuals 5, 16, 42, 68, 81and 107 displayed the highest diseaseintensity indexes during the study.

ConclusionThe results presented above show thatmutagenesis caused by irradiation with60Co did not give the cultivar ‘DominicoHartón’ any kind of tolerance to attackby yellow and black Sigatoka.

Studies performed by Cervantes(1997) show that irradiation with 60Co


Table 1. Relation between the percentage of final intensity of black or yellowSigatoka in clones and the lowest average severity taking into account the positionof the leaf after inflorescence formation.

Clone* Leaf Final intensity (%)

9 6 44.44

7 48.64

8 66.38

9 100.00

15 6 52.42

7 48.69

8 52.98

9 63.41

39 6 47.84

7 49.58

8 47.26

9 46.98

57 6 70.48

7 46.18

8 54.49

9 100.00

59 6 48.03

7 48.98

8 46.95

9 51.84

82 6 47.66

7 44.32

8 40.95

9 43.33

Control 6 48.24

7 48.50

8 47.79

9 45.96* Clones harvested at different dates.

Table 2. Behaviour of six irradiated ‘Dominico Hartón’ clones with regard to thecycle, the youngest leaf spotted, the number of leaves at evaluation and bunchweight (kg).

Clone Cycle (days after planting) YLS NLE Bunch weight (kg)

9 528 5 8 8.00

15 493 5 10 12.50

39 528 4 10 5.60

57 528 4 8 8.70

59 493 5 10 8.00

82 473 4 10 10.00

Témoin 486 5 9 10.60YLS = youngest leaf spotted

NLE = number of leaves at evaluation .

at different levels or degrees inducedmutations in ‘Williams’ banana that hadnegative effects on the phenotypic qual-ities of the plant and the fruit, makingthe latter unfit for sale. This somewhatreduces hopes for genetic improvementusing this mutagenic agent.

AcknowledgementsThe authors thank the InternationalAtomic Energy Agency (IAEA), Vienna,Austria, and COLCIENCIAS, Colombia,for their aid in this research conductedby the Línea de Investigación en Plá-tano, Departamento de Fitotecnia, Fac-ultad de Ciencias Agropecuarias, Uni-versidad de Caldas, Colombia. ■

ReferencesAguirre M.C., J. Castaño-Zapata, J.A. Valencia, L.E.

Zuluaga & C. Arce. 1998. Interacción de My-cosphaerella fijiensis Morelet y M. musicolaLeach en siete genotipos de Musa sp., en un árealímite de expansión de la Sigatoka negra en lazona cafetera colombiana. Pp. 192-220 in Memo-rias del Seminario Internacional sobre Produc-ción de Plátano (M.J. Giraldo, S.L. Belalcázar,D.G. Cayón y R.G. Botero, eds). Universidad delQuindío; Comité de Cafeteros del Quindío; SENA;INIBAP; CORPOICA.

Belalcázar S., F. Salazar, J.A. Valencia, C.H. Silva,M.I. Arcila & R. Jaramillo. 1994. Reacción de var-iedades mejoradas al ataque de Sigatoka negra(Mycosphaerella fijiensis Morelet). Pp. 192-214in Mejoramiento de la Producción del Cultivo delPlátano. ICA-CORPOICA; CIID; INIBAP; INPO-FOS; CCQ.

Burt J. A., J. Rutter & H. Gonzalez. 1997. Short dis-tance wind dispersal of the fungal pathogenscausing Sigatoka diseases in banana and plan-tain. Plant Pathology 46(4): 451–458.

Cervantes A. & A. Rodríguez. 1997. Algunas carac-terísticas fenotípicas de las mutaciones induci-das en banano Williams (Musa AAA) por las irra-diaciones de Cobalto 60 in Memorias V Congresode la Sociedad Colombiana de Fitomejoramientoy Producción de Cultivos. Santa Marta. 109 pp.

Craenen K. 1998. Black Sigatoka disease of bananaand plantain: a Reference Manual. IITA, Ibadan,Nigeria.

Gauhl F. 1994. Epidemiology and ecology of blackSigatoka (Mycosphaerella fijiensis Morelet) onplantain and banana in Costa Rica. INIBAP,Montpellier, France. 120 pp.

Jácome L. 1998. Sigatoka negra, la situación enAmérica Latina y el Caribe. Pp. 18-23 in Memo-rias Primer Simposio Internacional sobre Siga-toka Negra (M.M. Robles et al., compilers). Man-zanillo, Colima, Mexico, 8-10 de Julio 1998.SAGAR; INIFAP; INIBAP; Universidad de Colima;IICA.

Jacome L.H. & W Schuh. 1992. Effects of leaf wet-ness duration and temperature on developmentof black Sigatoka disease on banana infected byMycosphaerella fijiensis var. difformis. Phy-topathology 82(5): 515-520.

Alfonso Vargas and Fabio Blanco

Bunch trimming (selective handremoval) is performed in exportbanana cropping systems (Musa

AAA). However, reference informationis rare, contradictory and fragmentary.The increase in fruit size resulting fromselective hand removal is mentioned byIrizarry et al. (1989, 1992 and 1994),Johns (1996), Boncato (1969), Calvoand Soto (1984) and Meyer (1975). Nev-ertheless, the increase in fruit size doesnot compensate the decrease in bunchweight (Irizarry et al. 1989, 1992 and1994, Meyer 1985). This yield loss wasalso observed by Daniells (1987) andwas not accompanied by improvementin fruit grade or finger length.

Findings of Vargas et al . (1999)showed that the number of hands andtheir position on the bunch should beexamined first in evaluations of trim-ming. In this respect, the latter authorsfound no differences between the vari-ous intensities of trimming with regardto the dimensions of fruits from compa-rable hands positioned in the upper orlower part of bunches with the samenumber of hands at flowering.

The different methodologies used forthe evaluation of trimming may accountfor the lack of agreement between re-sults concerning fruit dimensions whichis frequently mentioned in the litera-ture.

The aim of the work presented here isto compare two methodologies for eval-

uating the trimming of bananabunches, using the same set of data.

Material and methods The data were collected in a bananazone (Musa AAA, cv. ‘Valery’) consid-ered to be highly productive. The plan-tation is 29 years old and located on theCaribbean coast of Costa Rica. It cur-rently has a density of 1750 plants/ha.

Trimming was performed two weeksafter the shooting of the inflorescenceand in all cases included the removal ofthe male flowers and the false hand.

The following treatments were per-formed on bunches with eight, nine andten true hands at flowering: 1) removalof one true hand and 2) removal of twotrue hands.

A hand is considered to be ‘false’when at least one set of pistillate flowersdevelops abnormally (with undevelopedovaries for example) or if staminateflowers are present. A group of pistillateflowers whose gynaecia develop nor-mally is considered to be a true hand.

Trimming was performed at randomin a 5-ha area, as the different types ofbunches appeared. Five trimming oper-ations were performed at two-monthlyintervals in April, June, August, Octo-ber and December. In conformity withthe plantation programme, fruits wereharvested during each 11th week aftertrimming in the first three cycles andduring weeks 11 and 12 for the last two.It was considered that each bunch wasa repetition. A total of 416 buncheswere appraised.


Methodological considerations inthe evaluation of banana bunchtrimming (Musa AAA, cv. ‘Valery’)

Agronomy Trimming for higher productivity

Mourichon X. & M.F. Zapater. 1990. Obtention invitro du stade M. fijiensis, forme parfaite de Cer-cospora fijiensis. Fruits 45(6): 553–557.

Orjeda G. in collaboration with the PROMUSAworking groups on Sigatoka and Fusarium. 1998.Evaluation of Musa germplasm resistance toSigatoka diseases and Fusarium wilt. INIBAPTechnical Guidelines 3. INIBAP, Montpellier,France.

Riveros A.S. & P. Lepoivre. 1998. Inductoresexógenos asociados con los mecanismos de de-fensa a la Sigatoka negra del banano. Pp. 126-132in Memorias Primer Simposio Internacionalsobre Sigatoka Negra (M.M. Robles et al., compil-

ers). Manzanillo, Colima, Mexico, 8-10 de Julio1998. SAGAR; INIFAP; INIBAP; Universidad deColima; IICA.

Claudia Milena Cardona Torres and GustavoAdolfo Yepes González are students at the Facul-tad de Ciencias Agropecuarias, Programa Agronomía,Universidad de Caldas. Jairo Castaño Zapata is Pro-fessor at the Departamento de Fitotecnía, Facultad deCiencias Agropecuarias. Universidad de Caldas, A.A.275, Manizales, Caldas, Colombia.

The dimensions of the fruits in eachbunch were recorded in the second,penultimate and last hands. In thebunches that did not have the samenumber of true hands (non-equivalentbunches), the treatments were com-pared in the last remaining hand (LRH)in addition to the second hand. Inbunches with the same number of truehands (equivalent bunches), the lastcomparable hands (LCH) were com-pared in addition to the second hand.

The LRH is defined as the last distalhand present after one of the two trim-ming treatments (Figure 1). The LCH isdefined as the last distal hand presentafter the most intense trimming treat-ment. It is the fifth hand in eight-handbunches, the sixth hand in nine-handbunches and the seventh hand in ten-hand bunches.

The following parameters were evalu-ated:a) bunch weightb) grade (1/32”) of the central fruit

(outer row) in the second hand, inthe last remaining hand (LRH) and inthe last comparable hand

c) finger length (cm) of the central fruit(outer row) of the second hand, theLRH and the LCH. The two method-ologies were compared by using thesame set of data. In the first, non-equivalent bunches and the LRH wereused for comparison purposes in addi-tion to the second hand. In the sec-ond, groups of equivalent bunchesand the LCH were used for compari-son, in addition to the second hand.Analysis of variance was performed onthe data in both cases to compare theeffects of the treatments.

ResultsAnalysis of all the data in which thenumber of hands was not taken into ac-count or where the LRH was used in ad-dition to the second hand to comparefruit dimensions (Table 1) reveals sig-nificant differences (P < 0.01) betweentrimming treatments with regard to thegrade and length of the central fruit inthe LRH. As trimming intensity in-creased, bunch weight decreased (P < 0.01). The dimensions of the cen-tral fruit in the second hand were not af-fected (P > 0.36) by trimming intensity.

Analysis of all the data in which thenumber of hands in the bunch wastaken into account and where the LCHwas used in addition to the second handto evaluate fruit grade and finger length(Table 2) did not reveal significant dif-ferences (P > 0.40) between the treat-ments, regardless of bunch size. How-ever, analysis allowing for the number ofhands in the bunch and using the LRHfor comparison (Table 2) reveals signifi-cant differences (P < 0.02) between thetreatments, regardless of bunch size.Bunch weight decreased with increas-ing trimming intensity for the buncheswith 9 and 10 hands (P < 0.01) but notfor those with 8 hands (P > 0.15). Thedimensions of the central fruit in thesecond hand of the bunches with 8, 9and 10 hands were not differentiated (P > 0.09) by trimming intensities.

DiscussionAn experiment can be defined as ‘a re-search study in which one deliberatelymanipulates one or more independentvariables (supposed causes) in order toanalyse the consequences of this ma-nipulation for one or more related vari-ables (supposed effects) in a situationcontrolled by the experimenter’(Hernández et al. 1998).

The independent variables (causes)represent the experimental treatmentswhich refer to experimental entities.The experimental entities assigned tothe treatments must be equivalent inall respects (homogeneous) or theirvariability must be duly controlledwithin the framework of the experimen-tal protocol.


Figure 1. Diagrammatic representation of equivalent bunches with measurement of fruit dimensions(grade and finger length) in the last remaining hand (LRH) and the last comparable hand (LCH).

Table 1. Measurements ± standard deviation of bunch weight, grade and length of the central lower finger (Musa AAA, cv.‘Valery’) of the second and last remaining hand (LRH) according to the trimming intensity (TI). All the bunches with 8, 9 and 10hands at flowering were taken into account.

TI1 n Bunch weight Fruit grade2 Finger length (cm) Fruit grade2 Finger length (cm)

(kg) 2nd hand 2nd hand LRH LRH

2 191 25.53 ± 0.35 43.26 ± 0.12 25.92 ± 0.11 39.50 ± 0.12 21.70 ± 0.09

3 225 23.84 ± 0.29 43.40 ± 0.12 26.00 ± 0.09 40.48 ± 0.14 22.49 ± 0.09

Prob > F 0.0001 0.3661 0.6507 0.0001 0.00011 Corresponding to the number of hands removed.2 One grade unit is 1/32 of an inch (0.79375 mm).

10 hand bunches

LCHLRH

False hand

Group of stamined flowers

True hands removed

In general, the effect of trimming ba-nana bunches has been studied withoutconsideration of the number of truehands present at flowering. Under theseconditions, it is very likely that non-equivalent groups received differenttreatments, invalidating the compari-son because of the resulting approxima-tion. In this case, the negative conse-quences for the quality of theexperiment are even more marked bythe use of the LRH for recording fruitdimensions (grade and finger length).The position of the finger in the bunchdepends on the size of the latter andthe trimming intensity. We know thatfinger length in a banana bunch (cv.‘Valery’) decreases from the first handto the last (Jaramillo 1982), with amore marked decrease from the fifthhand onwards. As a result, the LRHcannot achieve the equivalence be-tween hands required for the differ-ences between treatments to be as-sessed objectively. For this reason, it isinadequate for comparison of differenttrimming intensities.

The sources of invalidity mentionedabove can be eliminated by consideringeach bunch as an experimental entity,by applying treatments at random inthe field, by comparing bunches withthe same number of hands at floweringand by comparing hands in identicalpositions on the bunch (equivalentbunches and hands), as performed byVargas et al. (1999).

The results do not show that the high-est trimming intensity (removal ofthree true hands) results in an increasein the dimensions of fruits of the culti-var ‘Valery’ in comparison with the low-est intensity (removal of two truehands). Likewise, in agreement withthe previous analysis, it is confirmedthat the decrease in bunch weight isthe result of trimming.

The different conceptual analysis ofthe same set of data can explain the dif-ference in the results displayed in theresearch work based on one or other ofthe concepts. As a result, the methodol-ogy based on the use of non-equivalentbunches and hands and generally usedfor evaluation and analysis should nolonger be applied in research on thetrimming of banana bunches. Its usecould lead to erroneous results, as isdemonstrated in this study. Instead, re-searchers should use the secondmethod based on the use of equivalenthands and bunches. ■

ReferencesBoncato A. 1969. Effects of reducing the number of

hands in a bunch of Lacatan banana. Journal ofPlant Industry 32(3-4): 243-251.

Calvo J. & M. Soto. 1984. Efecto del desmane en lacalidad del fruto del banano (Musa AAA, Subgrupo Cavendish ‘Gran enano’). Pp. 128-129 in VICongreso Agronómico Nacional. Colegio de Inge-nieros Agrónomos de Costa Rica. San José, CostaRica.

Daniells J., P. O’Farrell, C. Mulder & S. Campbell.1987. Effects of bunch covering and bunch trim-ming on bananas in North Queensland. Queens-land Journal of Agricultural and Animal Sciences44(2): 101-105.

Hernández R., C. Fernández & P. Baptista, P. 1998.Metodología de la Investigación. (2da edición).McGraw-Hill Interamerican Editors, S.A. de C.V.México, D.F. 501 pp.

Irizarry H., E. Hernández & J. Rodríguez. 1994.Yield of five dwarf banana cultivars grown withminimum tillage in Puerto Rico’s mountain re-gion. The Journal of Agriculture of the Universityof Puerto Rico 78(1-2): 1-7.

Irizarry H., E. Hernández & J. Rodríguez. 1992.Bunch and ratoon management for profitableproduction of high quality bananas (Musaacuminata, AAA). The Journal of Agriculture ofthe University of Puerto Rico 76(3-4): 119-129.

Irizarry H., E. Hernández, E. Rivera, D.E.Beuchamp, E. Caloni, & R. Guadalupe. 1989. Per-

formance of elite bananas (Musa acuminataAAA) cultivars in four locations of Puerto Rico.The Journal of Agriculture of the University ofPuerto Rico 73(3): 209-221.

Jaramillo R. 1982. Las principales característicasmorfológicas del fruto de banano, variedadCavendish Gigante (Musa AAA) en Costa Rica.Unión de Países Exportadores de Banano(UPEB). 42 pp.

Johns G. 1996. Effects of bunch trimming and dou-ble bunch covering on yield of bananas duringwinter in New South Wales. Australian Journal ofExperimental Agriculture 36: 229-235.

Meyer J. 1975. Influence de l’ablation de mains surle rendement en poids des régimes de bananespar catégories de conditionnement aux Antilles.Fruits 30(11): 663-668.

Vargas A, J. Sandoval & F. Blanco. 1999. Efecto dela intensidad de desmane sobre las dimensionesdel fruto y el peso del racimo de banano (MusaAAA, cv. Valery). CORBANA 24(51): 85-92.

Alfonso Vargas works at the Dirección de Investiga-ciones de la Corporación Bananera Nacional (COR-BANA) Apdo. 390-7210, Guápiles, Costa Rica. FabioA. Blanco works at the Escuela de Ciencias Agrarias,Universidad Nacional, Apdo. 86-300, Heredia, CostaRica.


Table 2. Measurements ± standard deviation of bunch weight, grade and length of the central lower finger (Musa AAA, cv. ‘Valery’) of the second and last comparable hand (LCH) according to the trimming intensity (TI) and the total hands (TH) in the bunch. LRH = 6th and 5th if TH = 8; 7th and 6th if TH = 9; 8th and 7th if TH = 10; LCH = 5th if TH = 8, 6th if TH = 9 and 7th if TH = 10.

TH n TI Bunch weight Grade1 Finger length Grade1 LRH Finger length Grade1 LCH Finger length

(kg) 2nd hand 2nd hand (cm) LRH (cm) LCH (cm)

8 40 2 20.41 ± 0.47 43.19 ± 0.22 25.71 ± 0.22 39.60 ± 0.26 21.92 ± 1.18 41.01 ± 0.21 23.00 ± 0.17

51 3 19.43 ± 0.47 43.47 ± 0.25 25.63 ± 0.19 41.34 ± 0.42 23.21 ± 0.18 41.34 ± 0.43 23.21 ± 0.18

Prob > F 0.1510 0.4072 0.7710 0.0016 0.0000 0.5250 0.4033

9 73 2 24.24 ± 0.39 43.11 ± 0.18 26.64 ± 0.18 39.56 ± 0.18 21.68 ± 0.16 40.46 ± 0.16 22.55 ± 0.19

89 3 22.90 ± 0.28 43.48 ± 0.20 26.02 ± 0.14 40.46 ± 0.19 22.44 ± 0.14 40.46 ± 0.19 22.44 ± 0.14

Prob > F 0.0063 0.1916 0.0888 0.0001 0.0004 0.9945 0.6511

10 78 2 29.37 ± 0.42 43.44 ± 0.19 26.29 ± 0.18 39.38 ± 0.20 21.59 ± 0.14 39.97 ± 0.17 22.14 ± 0.15

85 3 27.49 ± 0.34 43.28 ± 0.20 26.18 ± 0.16 39.99 ± 0.17 22.10 ± 0.15 39.99 ± 0.17 22.10 ± 0.15

Prob > F 0.0006 0.5558 0.6606 0.0206 0.0138 0.9770 0.8702(1) One grade unit is 1/32 of an inch.

K. Nowakunda, P.R. Rubaihayo, M.A.Ameny and W. Tushemereirwe

Banana productivity in Uganda hasbeen declining since the 1970’s(Hartmanns 1989), mainly due to

low soil fertility, pest and disease buildup, low germplasm diversity and a hostof socioeconomic constraints (Rubai-hayo and Gold 1991). All the AAA-EAcooking bananas are susceptible toblack Sigatoka, banana weevils and ne-matodes (Tushemereirwe 1996).

The use of disease and pest resistantbanana cultivars has been suggested asthe most feasible solution to theseproblems (Ortiz and Vuylsteke 1998),and consequently, a number of bananahybrids and landraces resistant or tol-erant to mainly black Sigatoka and/orFusarium wilt have been introducedinto Uganda.

The physical, chemical and sensorycharacteristics of these cultivars weredetermined to establish their qualityprofile. The agronomic attributes of im-portance to banana end-users includedmaturity period and attainment of ac-ceptable eating quality at an early stageof development.

This paper reports the results of con-sumer acceptability of 14 introducedbanana and plantain cultivars for cook-ing and juice production.

Materials and methodsThe characteristics of the 14 cultivarstogether with East African Highland ba-nana landraces used in the study arepresented in Table 1. The most commonlandrace cultivars Mbwazirume,Kisansa (AAA-EA) cooking bananas,Ndizi (AB), Musa-Kayinja (ABB) andEntundu (AAA-EA) beer banana wereused as controls in a completely ran-domized block design experiment.

The fruit filling period was recordedas the period from shooting to the daywhen at least one finger indicated signsof ripening at which stage the bunchwas harvested (Palmer 1971). Thebunch weight (in kg) was taken at har-vest using a weighing scale (BFK-265-030B, 60, Fisher, UK). The finger weightwas determined by weighing five indi-vidual fingers from the second of thebunch on a Mettler (P1200, Fisher, UK)

electronic balance. The same fingerswere used for finger length, girth andpeel and pulp weights. Peel and pulpweights were determined by separatingthe peel and pulp by hand peeling witha stainless steel knife and weighing thepeel and pulp separately. Green-life wasdetermined by difference in days be-tween harvesting and when the secondhand showed first signs of ripening bycolour change from deep green to lightgreen (Dadzie and Orchard 1997). Thesamples for green-life monitoring wereharvested one week to the expectedphysiological maturity as defined byPalmer (1971). Tannin levels were de-termined using the Vanillin based assayas described by Broadhurst and Jones(1978).

Sensory characteristics and accept-ability were determined by boilingpeeled bananas in 1L of water. Sixgrams of table salt were added to thebananas and boiled until they were wellcooked. This method of preparation waspreferred to the traditional steamingand mashing (muwumbo) to avoid pre-sentation bias.

Fifteen panellists were selected onthe basis of functional taste buds usingdilute solutions of basic tastes: Sweet

(Sucrose at 8 g/l), Salty (Sodium chlo-ride, 1.5 g/l), Sourness (Citric acid, 0.25g/l), Bitterness (caffeine, 0.05 g/l)(Bainbridge et al. 1996).

The selected panellists were takenthrough a series of tests involving non-experimental bananas to allow them tolearn the various descriptors of bananaquality characteristics. Experimentalsamples were coded with four digits toeliminate name bias and presented tothe panellists. The panellists were re-quested to score the samples using a 6-point hedonic scale with 1 = extremeapproval and 6 = extreme disapprovalof a given attribute (Larmond 1987,Jellinek 1985) for the following charac-teristics: taste, texture, colour and ac-ceptability. Juice extraction was doneusing methods described by Kya-muhangire (1990).

The data were analyzed by the Gener-alized Linear Model (GLM) and analy-sis of variance (Mead et al. 1993). Themeans were separated using theFisher’s Unprotected LSD test at 0.05level of significance (Anon. 1994). Thecorrelation matrices were obtainedusing the Minitab correlation pro-gramme.

Results and discussionYield characteristicsThe results of yield characteristics arepresented in Table 2. The FHIA hybridshad similar maturing time as the AAA-East African highland landrace culti-vars, which gave FHIA hybrids an ad-



Improvement Tasting new varieties

Table 1. Characteristics of cultivars/hybrids used in the study.

Name Genome Origin Characteristics

Sigatoka Fusarium Weevils Mean bunch weight (kg)

FHIA-01 AAAA FHIA R R T 45.6





TMPx582/4 AAAB IITA T R T 16.9

TMPx5511/2 AABB IITA T R T 17.9


PV 03-44 - IITA T R T 25.7



Pisang Ceylan AA IITA T R T 17.2

Yangambi km5 AAA IITA R R T 25.1

Saba ABB IITA T R T 16.7

*Mbwazirume AAA Landrace S R S 15.6

*Kisansa AAA Landrace S R S 16.5

+Entundu AAA Landrace S R S 16.1

+Kisubi AB Landrace S S T 12.6

+Pisang awak ABB Landrace S S T 14.2S = Susceptible, T = Tolerant, R = Resistant.

* Cultivars used as control for cooking tests.

+ Cultivars used as control for juice yield.

vantage over the IITA hybrids. However,both the FHIA and IITA hybrids pro-duced significantly (P < 0.05) heavierbunches than the East African highlandcooking bananas suggesting a clear ad-vantage over the East African highlandbanana cultivars in the study with re-spect to bunch sizes. Banana producersand consumers prefer cultivars with bigbunches (Ssemwanga and Thompson1994, Dadzie and Orchard 1997).

Fruit characteristicsThe results of peel weights indicatedthat FHIA-01, FHIA-03, FHIA-23 andthe IITA hybrids were not significantly

(P < 0.05) different from Mbwazirume,a local AAA-EA cooking banana lan-drace. Saba, Yangambi Km5 andKisansa respectively had the lowestpercentage of peels indicating morepulp which is a clear advantage forcooking, juice, dessert and roasting ba-nanas. All the IITA hybrids had longerfingers and lower peel percentagescompared to the rest of the bananas.

Data from fruit girth measurementsshowed that the fruit circumference ofSaba and TMPx 5511-2 was significantly(P < 0.05) larger than those of the AAA-EA cooking bananas. Yangambi km5,Pisang Ceylan, TMPx 548-4 and FHIA-23

had the smallest circumference. Largefingers are a preferred banana charac-teristic (Dadzie and Orchard 1997) andtherefore an advantage.

Shelf lifeThe results of shelf life study for the ba-nana cultivars harvested at one weekbefore their expected physiological ma-turity as defined by Palmer (1971) indi-cated that Kisansa had significantly (P< 0.05) longer shelf life than the othercultivars studied. Bananas are usuallyharvested when they are a maturegreen for ease of transportation to themarkets. The consumers also use thebananas piecemeal over time ensuringa clear advantage for banana cultivarswith a long shelf life.

The EA-AAA cooking banana lan-draces had significantly (P < 0.05)lower dry matter than the other culti-vars studied suggesting considerabledisadvantage in terms of yield improve-ment during breeding (Anon. 1993).The results of tannin (polyphenols) andsensory analyses of the cultivars indi-cated that the EA-AAA cooking bananalandraces had significantly (P < 0.05)lower tannin than the introduced culti-vars which had an unacceptable astrin-gent taste (Table 3).

Sensory analysisThe results of the sensory analysis fortaste, texture, colour, flavour and ac-ceptability of the cooked bananas indi-cated that the introduced bananas andplantains had significantly (P < 0.05)poorer scores than the East Africanhighland bananas (Table 3). The tex-


Table 2. Major physical characteristics of the banana cultivars under study.

Cultivar Genome HST (days) BWT (kg) Peel (%) FC (cm) FL (cm) FW (gr) DM (%) SF (days)

FHIA-01 AAAA 133.0bc 33.9a 44.0a 14.3b 24.0b 121.7d 29.3e 7.6af

FHIA-02 AAAA 129.7c 28.3ab 32.0b 14.2b 21.7c 116.3gf 28.4ed 5.3ch

FHIA-03 AAAA 122.7c 31.8ab 44.0a 14.2b 22.0bc 113.0e 30.6dj 5.6ch

FHIA-17 AAAA 124.3c 32.1ab 41.6ab 14.3b 23.0b 120.7d 29.3e 7.6af

FHIA-23 AAAA 128.0c 33.0ab 44.5a 13.2bc 23.3b 123.3d 31.1d 7.6af

TMPx582-4 AAAB 144.0ab 16.0c 40.9ab 14.6b 25.7a 130.0c 35.4b 7.3ad

TMPx5511-2 AABB 147.7ab 20.9c 39.4abc 17.0a 25.6a 135.0b 33.2c 8.0a

TMPx548-9 AAAB 143.0ab 21.7bcd 39.0abc 14.7b 24.3ab 121.7d 33.0c 7.6af

PV03-44 AAAA 152.0a 19.5c 27.8d 14.2b 24.7ab 141.0a 29.0e 7.3ad

TMPx548-4 AAAB 150.7a 16.5c 39.0abc 13.0bc 24.7ab 139.0a 38.3a 7.3ad

TMPx7002-1 AAAB 150.7a 18.9c 42.8a 14.0b 24.0ab 106.7j 34.7c 7.0ad

Pisang Ceylan AA 150.0a 23.1bcd 27.7d 13.0bc 19.9c 108.7j 27.6f 7.0ad

Yangambi km5 AAA 148.7ab 27.2ab 29.8d 13.1bc 19.6c 129.0c 25.9g 6.0cd

Saba ABB 159.0a 19.5c 18.2e 16.0a 23.3b 114.3ef 29.6e 6.0cd

Mbwazirume AAA-EA 122.0c 19.5c 37.8abc 14.7b 23.6b 114.0ef 17.8h 8.6a

Kisansa AAA-EA 120.0c 20.0c 30.0d 14.3b 24.9ab 122.5d 18.3h 9.3e

LSD (0,05) 16.4 6.3 4.2 1.7 2.4 2.9 1.9 1.53

CV (%) 17.02 15.50 22.59 7.43 8.52 2.85 4.00 9.38Means with same letters in a column are not significantly different (0.05%).

All the measurements were limited to the 2nd hand of the freshly harvested physiologically mature bunches.

Peels were measured as the total waste from a whole finger.

HST = harvest maturity date; BWT = bunch weight; FC = fruit circumference; FL = fruit length; FW = fruit weight; DM = dry matter weight; SF= shelf-life.

LSD = Standard error of the differences.

CV = Coefficient of variation.

Table 3. Scores of the sensory characteristics and acceptability of the cooked newlyintroduced banana cultivars.

Cultivar Genotype Tannin Taste Flavour Colour Texture Acceptability

FHIA-01 AAAA 0.207e 3.0e 4.0ce 3.9cd 4.0f 3.0g

FHIA-02 AAAA 0.444ab 4.0d 4.0ce 4.0cd 5.0b 5.0l

FHIA-03 AAAA 0.598a 5.7a 4.7b 5.6a 2.8c 5.9a

FHIA-17 AAAA 0.302b 3.4e 4.4be 4.8b 2.6c 4.0c

FHIA-23 AAAA 0.399b 3.0e 4.0ce 4.8b 2.7c 4.0c

TMPx582-2 AAAB 0.600ac 4.6bc 4.6be 3.9cd 5.4a 5.2bi

TMPx5511-2 AABB 0.490b 4.9b 4.9b 3.5c 5.6a 5.6ab

TMPx548-9 AAAB 0.500ad 4.9b 5.9a 4.3bd 5.3a 5.3bi

PV03-44 - 0.522ab 4.3cd 5.3a 4.9b 5.4a 5.6ab

TMPx548-4 AAAB 0.404b 3.5af 4.5b 4.8b 5.3a 5.2bi

TMPx7002-1 AAAB 0.408b 4.6b 4.6b 3.7c 5.0b 5.3bi

Pisang Ceylan AA 0.570a 5.6a 5.6a 4.5b 5.4a 5.9a

Yangambi km5 AAA 0.670a 4.3a 4.6b 4.4b 5.5a 4.7hi

Saba ABB 0.670a 5.3a 5.3a 4.9b 5.5a 5.6a

Mbwazirume AAA-EA 0.008d 1.4f 1.4d 1.9e 2.0d 2.1e

Kisansa AAA-EA 0.010d 1.5f 1.5d 1.6e 1.6d 1.3f

LSD (0.05) 0.1582 0.5049 0.7049 0.5329 0.5095 0.5736

CV (%) 24.02 17.42 18.42 20.24 16.34 17.33Means with same letters in a column are not significantly different (at 0.05).

Scale: 1 = extremely good; 6 = extremely poor.

tural attribute in bananas has beenclassified in sensory terms as ‘hard’,‘medium’ or ‘soft’ (Ssemwanga et al.1996). The panellists rejected the tex-tural attributes of the hybrids describ-ing it as ‘hard’ and therefore ‘unaccept-able’. Ugandan consumers dislikecooked bananas, which lack a ‘soft’ tex-ture (Ssemwanga and Thompson 1994).

Results also indicated that colour andtaste attributes in the introduced ba-nanas were significantly (P < 0.05)poorer than the AAA-EA cooking ba-nanas. The panellists complained of apuckering sensation in the mouthcaused by the introduced cultivars andpoor flavour implying that they are infe-rior as cooking bananas.

General acceptability General acceptability, the final judge-ment of the panellists for the cultivars,summing up all the perceptions indi-cated that all the introduced bananacultivars were significantly (P < 0.05)inferior to the AAA-EA cooking ba-nanas. All the IITA hybrids and FHIA-03scored 5 and above indicating total re-jection. FHIA-01 had an acceptabilityscore of 3.0 which was the closest to theAAA-EA cooking bananas. The accept-ability results were in conformity withthe reports that the hybrid bananaswere superior to landraces with respectto fruit and bunch physical characteris-tics but inferior to them with respect touse quality (Anon. 1993, Ssemwangaand Thompson 1994, Sebasigari 1996,Mwenebanda and Banda 1996).

The results of correlation matrixamong the studied characteristics ofthe cultivars indicated that the rela-tionship between tannin and colour wasclose (r = 0.81) as reported by Macheix

et al. (1990) (Table 4). The highly posi-tive correlation value for tannin andcolour suggests that the high tanninnegatively affects the appearance of thecooked bananas. The correlation coeffi-cient between texture and acceptability(r = 0.77) suggested that the cultivarswith hard texture would be unaccept-able to the consumers. The correlationcoefficient between taste and accept-ability was 0.89, suggesting that tastesignificantly (P < 0.05) influences ac-ceptability as observed by Ssemwangaand Thompson (1994) and Sebasigari(1996).

The correlation between fibre andacceptability (r = 59) was significant(P < 0.05) suggesting that the amountof crude fibre was important for accept-ability. The correlation between drymatter and texture was significant (P < 0.05) (r = 0.61) suggesting thatcultivars with high dry matter wouldhave a hard texture and hence becomeunacceptable. This may account for thelow acceptability and hard texture ofthe IITA hybrids since they were foundto have high dry matter. The relation-ship between tannin and texture sug-gested that cultivars with high tanninhad unacceptable texture. The relation-ship between maturity date and accept-ability was also significant (P < 0.05) (r = 68) suggesting that the cultivarsthat take longer to mature were less acceptable.

The results of juice yield indicatedthat only FHIA-03, FHIA-01, Yangambikm5 and Saba yielded juice (Table 5).FHIA-03 yielded a significantly (P < 0.05)higher percentage of juice than the lan-drace Entundu and the locally adaptedMusa-Kayinja and Kisubi. Yangambikm5, FHIA-01, and Saba had similar

juice yields as Entundu, a traditionalAAA-EA juice banana. The low juiceyielders produced juice of significantly(P < 0.05) higher brix than the highjuice yielders. Normally, juice is con-sumed or processed further after dilu-tion to acceptable sweetness. Accept-able sweetness has been established tocoincide with a brix of between 12%-14% (Pekke, personal communication)which explains why banana juice is nor-mally diluted before drinking. What ap-pears to be a disadvantage of havinglower brix is compensated for by higherjuice yields. The pH of the juices fromFHIA-01 and Entundu was similar andsignificantly (P < 0.05) higher than thatof other cultivars that could producejuice. The pH is an important attributeof juices because it influences the lev-els and type of contamination andtherefore the kind of preservation nec-essary (Jay 1987). Low pH has lowerlevels of microbial contamination and,therefore, less need of stringent preser-vation methods (Jay 1987).

The taste of Kisubi juice was scoredas significantly (P < 0.05) better thanthe juices from most of the other culti-vars studied. This cultivar also had thelowest pH (4.5). Saba and FHIA-01 pro-duced juice with significantly (P < 0.05)better mouthfeel than local beer ba-nana cultivars. Mouthfeel is a measureof smoothness of the juice hence an im-portant quality characteristic (Koffi et al. 1991).

The good yield and characteristics ofthe juice combined with big bunches,black Sigatoka and Fusarium wilt resis-tance make FHIA-01, FHIA-03, Yangambikm5 and Saba good candidates forjuice/beer production in places of thecountry where brewing is an important


Table 4. Correlation of the physical, chemical and sensory characteristics of the study cultivars.

MD BW FW FL FC PP % DM % TSS % TNN PR AS FB TT FV CL TX AC

MDBW -0.533* -

FW 0.263 -0.241 -

FL 0.019 -0.463 0.447 -

FC 0.104 -0.229 0.064 0.506* -

PL % -0.446 0.358 0.013 0.297 -0.113 -

DM % 0.532* -0.108 0.292 0.268 0.008 0.357 -

TSS % -0.121 0.186 -0.016 0.171 0.306 0.151 0.394 -

TNN 0.663* -0.087 0.282 -0.180 0.130 -0.230 0.640* 0.274 -

PR -0.566 0.104 0.074 0.392 0.102 0.139 -0.432 0.174 -0.528* -

AS -0.371 0.061 0.187 0.146 -0.227 0.213 -0.326 -0.408 -0.307 0.233 -

FB 0.601* -0.432 0.219 0.260 0.304 -0.093 0.567* 0.034 0.754* -0.365 -0.008 -

TT 0.614* -0.046 -0.098 -0.267 0.151 -0.171 0.598* 0.263 0.832* -0.587* -0.408 0.603* -

FV 0.699* 0.008 0.131 -0.162 0.035 -0.112 0.725* 0.220 0.793* -0.636* -0.310 0.508* 0.891* -

CL 0.499 -0.007 -0.098 -0.377 -0.076 -0.120 0.595* 0.230 0.810* -0.535* -0.424 0.560* 0.839* 0.719* -

TX 0.901* -0.391 0.292 -0.052 0.115 -0.329 0.614* 0.095 0.728* -0.556* -0.431 0.489 0.700* 0.771* 0.595* -

AC 0.678* -0.135 0.086 -0.184 0.064 -0.123 0.725* 0.376 0.861* -0.580* -0.438 0.594* 0.938* 0.901* 0.818* 0.766* -MD = Maturity date (fruit filling period); BW = Bunch weight; FW = Fruit weight; FL = Fruit length; FC = Fruit circumference; PL % = Percentage peels; DM % = Percentage dry matter; TSS % =Percentage total soluble solids; TNN = Tannin (absorbance values); PR = Protein; AS = Total Ash; FB = Crude fibre; TT = Taste; FV = Flavour; TX = Texture; CL = colour; AC = Acceptability.

* Significant coefficients.

economic activity and the traditionalcultivars are being wiped out by pestsand diseases.

ConclusionsResults of the study indicated thatwhile the introduced cultivars had bigbunches and fruits, their cooking quali-ties were unacceptable to consumersdue to high tannin, hard texture andpoor taste compared to AAA-EA cookingbananas.

Cultivars FHIA-01, FHIA-17 andFHIA-23, however, had ratings thatcould make them acceptable for cook-ing in parts of the country where thecooking banana landraces are disap-pearing. Cultivars FHIA-01, FHIA-03,Yangambi km5 and Saba with goodquality juice can replace the traditionallocal juice producing cultivars wherethese are disappearing. ■

ReferencesAnonymous. 1993. Plantain/Banana improvement.

Annual Report, IITA.Anonymous. 1994. SAS/STAT users’ guide. Version 6,

4th ed., Vol. 2. Cary CN. SAS Institute Inc. 846 pp.Bainbridge Z, K. Tomlins, K. Wellings & A. Westby.

1996. Methods for assessing quality characteris-tics of non-grain starchy staples. Part 3: Labora-tory methods. NRI, UK. 70 pp.

Broadhurst R.B. & W.T. Jones. 1978. Analysis ofcondensed tannins using acidified Vanillin. Jour.Food Sc. & Agric. 29: 77-79.

Dadzie B.K. 1998. Postharvest characteristics ofblack Sigatoka resistant banana, cooking bananaand plantain hybrids. Inibap technical guidelinesNo. 4. 75 pp.

Dadzie B.K. & J. E. Orchard. 1997. Routine posthar-vest screening of banana/plantain hybrids: crite-ria and methods. Inibap technical guidelines No. 2. 63 pp.

Hartmanns E. 1989. Five-year food crops researchplan (1989-1994) and recommendations forstrengthening research and extension linkages.MAAIF, Uganda.

Jay M. J. 1987. Modern food microbiology. 3rd ed.,CBS Publ. India.

Jellinek G. 1985. Sensory evaluation of food. Theoryand practice. Food Tech Journ. 14: 33-60.

Koffi E.K., C.A. Sims & R.P. Bates. 1991. Viscosityreduction and prevention of browning in the pre-paration of clarified banana juice. Journ. of foodquality, University of Florida, Gainesville, USA.14 (3): 209-218.

Kyamuhangire W. 1990. Banana juice extractionand processing. M.Sc. Thesis. University of NewSouth Wales, Kingston, Australia.

Larmond E. 1987. Sensory evaluation can be objec-tive. Pp. 3-14. in Objective methods in food qua-lity assessment No. 1. CRC Press Inc., BocaRaton, Florida.

Macheix J.J., A. Fleuriet & J. Billot. 1990. Fruit phe-nolics. CRC Press Inc., Boca Raton, Florida. Pp10-22.

Mead R., R.N. Curnow & A.M. Harsted. 1993. Statis-tical methods in agriculture and experimentalbiology. Chapman and Hall, London. 415 pp.

Mwenebanda B.M.L & D.L. Banda. 1996. Perfor-mance of the advanced Musa yield trial in Ma-lawi. MusAfrica 10:11.

Ortiz R. and D. Vuylsteke. 1998. Bita-3, a starchy ba-nana with a partial resistance to black Sigatokaand tolerant to streak virus. Hort. Sci. 33: 358-359.

Palmer J.K. 1971. The biochemistry of fruits andtheir products. 11: 65-105. Academic press, Lon-don.

Rubaihayo P.R. & C. Gold. 1991. A Report on RapidRural Appraisal Survey of Banana Production.Banana Cropping Systems Research. Dpt. of CropSci. Makerere University. Research Bulletin 2.

Sebasigari K. 1996. Characterisation of exotic bana-nas to determine their fruit utilisation accordingto food habits in East Africa. MusAfrica 10: 7.

Ssemwanga J.K., A.K. Thompson & J.A. Aked. 1996.Quality and acceptability studies of the bananahybrid FHIA-03 as compared to the indigenouscultivars for matooke preparation. Ph.D thesispresented to University of Reading, U.K.

Ssemwanga J.K. & A.K. Thompson. 1994. Investiga-tion of postharvest and eating qualities likely toinfluence acceptability of matooke banana culti-vars to be introduced in Uganda. Aspects of ap-plied biol. 39: 207-213.

Tushmereirwe W. K. 1996. Factors influencing theexpression of leafspot diseases of highland bana-nas in Uganda. A Ph.D thesis submitted to theUniversity of Reading, Department of Agricul-ture, UK.

K. Nowakunda and W. Tushemereirwe work atKawanda Agricultural Research Institute, Banana Pro-gramme, PO Box 7065, Kampala, P.R. Rubaihayoand M.A. Ameny, at Makerere University, Faculty ofAgriculture, PO Box 7062, Kampala, Uganda.


Table 5. Juice Yield and juice characteristics of the recently introduced banana cultivars.

Cultivar GEnotype Pulp weight (kg) Juice yields (%) Brix (%) pH Taste Colour Mouthfeel

FHIA-01 AAAA 2.0 63.4bc 20.08c 5.1a 2.5a 2.0 1.8cd

FHIA-02 AAAA 2.0 0.0 - - - - -

FHIA-03 AAAA 2.0 76.5a 21.70bc 4.7bc 2.8a 2.3 2.8ab

FHIA-17 AAAA 2.0 0.0 - - - - -

FHIA-23 AAAA 2.0 0.0 - - - - -

TMPx582-2 AAAB 2.0 0.0 - - - - -

TMPx5511-2 AABB 2.0 0.0 - - - - -

TMPx548-9 AAAB 2.0 0.0 - - - - -

TMPx548-4 AAAB 2.0 0.0 - - - - -

TMPx7002-1 AAAB 2.0 0.0 - - - - -

Pisang Ceylan AA 2.0 0.0 - - - - -

Yangambi km5 AAA 2.0 67.1b 20.92c 4.8b 2.3ab 2.3 2.0c

Saba ABB 2.0 65.3bc 22.00bc 4.6cd 2.5a 2.3 1.5d

Kisubi AB 2.0 52.7d 25.58a 4.5d 1.5b 2.3 2.8ab

Entundu AAA-EA 2.0 68.5b 19.83c 5.1a 2.8a 2.8 3.0b

Musa-Kayinja ABB 2.0 60.5c 24.00ab 4.8b 2.3ab 2.3 2.5b

LSD (0.05) 5.77 2.808 0.02 0.85 NS 0.46

CV (%) 33.7 0.76 2.86 24.78 21.17 44.59* Data analysed was that from the seven cultivars which produced juice.

Bakelana-ba-Kufimfutu and Mpanda

Banana is an important crop in theDemocratic Republic of theCongo, lying in second position

after cassava, and the fruits are a veryimportant part of the diet of the popula-tion. Dessert bananas are eaten as soonas they are ripe, and plantain isprocessed to form a paste called ‘Lituma’or boiled and mixed with other foods.

The development of banana cultiva-tion requires the improvement of cul-tural practices and planting material(suckers). Farmers find it very difficultto obtain sufficient quantities of plant-ing material to increase the size of areaunder cultivation.

There are several sucker multiplica-tion techniques. It is difficult to obtainsuckers in sufficient quantities whenthey are needed through the naturalmultiplication method used by mostfarmers. The false decapitation methodfound to give good results in experimen-tal trials does not satisfy the require-ments of farmers who do not wish todelay their harvests.

Bananas multiplied naturally fromsuckers have low bunch yields in com-parison with tissue culture plants (Ade-laja 1995). However, tissue culture is notaccessible to farmers because of thecost and the infrastructure required.

Noupadja (1995) compared threemethods for the rapid multiplication ofsuckers: false decapitation, total decap-itation and inclination of the pseu-dostem. The best results were obtainedwith false decapitation with an averageof 12 suckers obtained 9 months afterplanting. In parallel, the Centre derecherches régionales sur bananiers etplantains (CRBP), established inCameroon, produced 8 to 14 suckers 10

months after planting using false de-capitation (CRBP 1996).

Other rapid multiplication methodsinvolving the fragmentation or decorti-cation have been tested at CRBP. Cormdecortication made it possible to obtain30 to 80 suckers in a short time (CRBP1996). Decorticating corms that had al-ready flowered gave better results thancorms that had not yet flowered (Bontéet al. 1995, CRBP 1996).

An evaluation of the corm decortica-tion method was undertaken at Univer-sité Protestante de Kimpese to test thevalidity of previous results. Only mothercorms were decorticated; daughtersuckers were separated as soon as theyhad three opened leaves.

Material and methodsLocationThe corm decortication trial was per-formed at Université de Kimpese, 222 kmalong the main road from Kinshasa toMatadi at elevation 337 m. Average an-nual precipitation varies from 900 to1500 mm and average annual tempera-ture is around 25°C.

TreatmentsEighteen dessert banana plants weregrubbed up. Nine of these had not flow-ered and nine had flowered (i.e. hadproduced a bunch of bananas). The fol-lowing treatments were applied:1. Corm from non-flowered plant, not

split2. Corm from non-flowered plant, split

in two3. Corm from non-flowered plant, split

in four4. Corm from flowered plant, not split5. Corm from flowered plant, split in

two6. Corm from flowered plant, split in

four

LayoutNon-flowered 1 2 3Flowered 4 5 6A fully randomized experimental blockdesign with two repetitions was used.The pseudostems were separated andthe leaf sheaths were carefully removedfrom the corms.

Two superimposed sheaths determinea lateral bud at the low point or ‘V’where they meet. The number of buds istherefore the same as the number ofleaves possessed by the plant. The budsof old leaves are more visible thanthose of very young ones. Precautionswere taken not to damage the visiblebuds that had greater potential for de-velopment under favourable conditions.After decortication, the apical meris-tem of the non-flowered corms wasdamaged to activate the growth of thelateral buds. Regular watering was per-formed throughout the duration of eval-uation. The following parameters wereobserved:1) Number of days to the start of bud

growth2) Number of daughter suckers pro-

duced by each corm3) Sucker height at separation from the

cormEach shoot was weaned from the mothercorm at the 3-leaf stage. After decortica-tion, all the corms were planted in a claysubstrate.

Results and discussionThe results are shown in Table 1.

Statistical analysis of the data revealssignificant differences in the number ofdays to the start of growth of lateralbuds and in sucker height.• Influence of age: the lateral buds de-

velop more rapidly on the floweredplants. This can be explained by the


Agronomy A simple method for suckering

Table 1. Influence of corm age and the number of cuts on the start of growth of lateral buds, the number of suckers producedand sucker height.

Corn age Number of cuts Number of days to start of bud growth Number of suckers Sucker height (cm)

Non-flowered plant 0 cut 47 2 18

2 cuts 39 2 20

4 cuts 33 7 22

Flowered plant 0 cut 31 5 28

2 cuts 27 8 33

4 cuts 18 7 35

LSD (0.5) 4.50 NS 3.4

CV (%) 9.36 52.7 8.3


fact that the old corms have ripe budsand nutritional reserves that enhancetheir development.

• Influence of the number of cuts: budgrowth started more rapidly in thetreatment with four cuts. Competi-tion between growing buds is weakerin split corms. Dominance is more ac-tive in the non-split corm.

• Number of suckers grown: the flow-ered plants produced more suckersbut the difference is not significant.This confirms the results obtained inthe past (Bonté et al. 1995, CRBP1996). Fewer suckers were obtainedthan in experiments by CRBP. How-ever, our study was limited to thedecortication of the mother-cormwhereas the CRBP tests also includedthe decortication of the daughtersuckers and possibly granddaughtersuckers before sucker removal. Thesuckers grown from the corms of flow-ered plants were larger than thosegrown from non-flowered plants.Growth of suckers from corms of flow-ered corms with four cuts was greaterthan that of the other suckers.

Conclusion and recommendationsThe multiplication of suckers fromdecorticated banana corms is a simpleand inexpensive method. The healthycorms left in the field after harvestingcan be recovered and used to producethe suckers needed by farmers. ■

ReferencesAdelaja B.A. 1995. Rapid on-farm multiplication

technique for plantain and banana. MusAfrica 8:6.

Bonté E., R. Verdonck & L. Grégoire. 1995. La multi-plication rapide du bananier et du bananierplantain au Cameroun. Tropicultura 13(3): 109-116.

CRBP. 1997. Rapport annuel 1996. Centre deRecherches Régionales sur Bananiers et Plan-tains, Douala, Cameroon.

Noupadja P. 1995. Study of three field multiplica-tion techniques for generating planting materialof in vitro propagated plantain (Musa cv. AAB).MusAfrica 8: 7-8.

Bakelana-ba-Kufimfutu works at the Institut National pour l’Étude et la Recherche Agronomique,BP 2007, Kinshasa I, Democratic Republic of Congo,and Mpanda at the Université Protestante de Kimpese, Bas-Congo, Democratic Republic of Congo.


Rema Menon

Banana is the most important trop-ical fruit crop of Kerala state,which occupies the southwestern

portion of the Indian peninsula. Beinglocated within the centre of diversity ofcultivated banana, Kerala along withtwo other south Indian states – TamilNadu and Karnataka – are known forthe varied genetic resources, especiallythe AAB, AB and ABB genomic groupsunder the Eumusa series of edible ba-nana (Stover and Simmonds 1987). Al-though an array of varieties is grown inKerala, the French plantain cultivarNendran (AAB) is the most widespreadand highly valued as a dessert andcooking banana. Nearly 50% of the ba-nana production within the state is de-rived from the commercial cultivationof this variety. Other prominent culti-vars include Poovan (AAB), Rasthali(AAB), Red Banana (AAA), DwarfCavendish (AAA), Robusta (AAA), Kun-nan (AB) and Monthan (ABB), the cul-tivation of which is restricted to thehome gardens and provides an impor-tant source of rural income.

The Banana Research Station (BRS),Kannara, functioning under the KeralaAgricultural University (KAU), hasamong its major objectives the collec-tion, conservation and evaluation of ba-nana germplasm. The station holds acollection of 225 accessions conservedin field genebank and comprises indige-nous and exotic material. The acces-sions have been characterized and eval-uated using the INIBAP/IPGRI Musadescriptors. The present paper outlinesthe work carried out during 1994-1997relating to the preliminary evaluation ofsome banana introductions.

Materials and methodsTwenty-two accessions from INIBAP’sMusa collection (ITC series) receivedin 1994 through the National Bureau ofPlant Genetic Resources (NBPGR),New Delhi, formed the experimentalmaterial. The accessions were receivedas small suckers of sample size one totwo, derived from tissue-culturedplants. The suckers were first estab-lished in pots and subsequently trans-ferred to experimental field at BRS.The site is located at an elevation of 58masl. The average temperature of theregion is 28°C and the annual rainfallranges between 2700 and 3000 mm, dis-tributed between two rainy seasons.Relative humidity varies between 77and 94%. Observations recorded on thefirst crop showed that 14 out of the 22accessions were represented in the sta-tion’s banana germplasm. Of the re-maining eight, three accessions viz.Three Hands Planty (ITC1132), ThreeVert (ITC1127) and Foconah (ITC649)could not be established. Finally thefollowing five exotic accessions were se-lected for further evaluation (Table 1).

Five suckers of each cultivar wereplanted in single rows in a compact plotadopting a distance of 2.5 m betweenrows and 2 m within row. Since three ofthe test cultivars turned out to plantaintypes, two indigenous plantain culti-vars, Nendran and Myndoli wereplanted along for comparison. Observa-tions on growth in terms of plantheight, pseudostem girth, number offunctional leaves at shooting and plantcrop cycle were recorded. Other vari-ables observed include bunch weight,number of hands and number of fruits.Pulp/peel ratio and the recovery ofchips in the plantain cultivars were alsoassessed.

Preliminary evaluation of some banana introductions in Kerala (India)

Improvement New evaluation in India

Tableau 1. Accesions selected for further evaluation.

N° Cultivar name Genome ITC code

1 Big Ebanga AAB 1129

2 Njock kon AAB 1133

3 Nyombe AAB 1124

4 Yangambi km5 AAA 1123

5 Popoulu AAB 1135

6 Nendran* AAB

7 Myndoli* AAB* Indigenous French Plantain cultivars.

Results and discussionThe French plantain cultivar, Nendran,indigenous to southwest India and rep-resented by several ecotypes (Jacob1952) is the most predominant bananacultivar of Kerala and plays a key rolein the income security of rural people.There is a limited cultivation of TrueHorn plantain, while False Horn culti-vars are not seen grown anywhere inIndia.

The two exotic French plantain culti-vars Njock kon and Nyombe and theFalse Horn plantain cultivar Big Ebangashowed very good adaptability and areconsidered useful introduction as far asKerala is concerned.

The data on vegetative characters ofthe introductions and local cultivarspresented in Table 2 showed variationin plant height and pseudostem girth.Njock kon, with a robust pseudostem(76.3 cm) was of shorter stature (250 cm)as compared to Nendran which aver-aged 271 cm. The growth habit, charac-terized by strong overlapping of leaves,was suggestive of dwarfism in this culti-var, a valuable trait in terms of en-hanced wind-resistance and easy har-vest. Big Ebanga and Nyombe weretaller than Nendran. Nyombe, charac-terized by robust, red-purple-colouredpseudostem and growing to a height of400 cm was taller than the local giantplantain cultivar Myndoli. The cropcycle in all the three plantain introduc-tions were longer compared to the localcultivars. However a crop duration of335 days observed in Big Ebanga madeit suitable to be fitted into the annualcrop cycle preferred for plantain culti-vars in Kerala. The long crop cycle inrespect of Nyombe promoted the infes-tation by pseudostem weevil(Odoiporus longicollis) which in re-cent years has emerged as a devastatingpest of banana in Kerala.

With regard to bunch yield, BigEbanga averaged 14.3 kg and was supe-rior to Nendran which weighed 10.9 kg.The number of fruits per bunch washigher in Nendran. The bunch weight inNjock kon and Nyombe which averaged25 and 32 kg respectively was higherthan in Nendran. Since unripe fruits of

plantain find extensive use in thepreparation of banana chips, the suit-ability of the exotic plantain cultivars incomparison to local cultivars for thispurpose was assessed. Big Ebanga reg-istered a chips recovery of 34.7% whichwas higher than that in Nendran andthe other plantain cultivars, which wasin the range of 29 to 30%.

Popoulu with short, thick and bluntfruits proved to be an interesting intro-duction. There are no records of itsbeing cultivated in any part of India.The plant height averaged 262 cm andthe crop cycle was completed in314 days. The bunch with 6 hands and51 fruits weighed on an average 9.5 kg.Ripe fruit pulp bore a striking resem-blance to that of Nendran. Yangambi km5described as a variety with sub-acidflavour (Daniells and Bryde 1995)showed very good establishment andconstituted a valuable addition to thegermplasm due to its high resistance toyellow Sigatoka leaf spot, one of the se-rious diseases and yield-reducing factorof banana in Kerala. The plants had asemi-tall stature which averaged 226 cm.The bunches with attractive, well-filledlight green fruits and agreeable flavourweighed 13.5 kg, consisting of 9 hands

and 132 fruits. The yield was compara-ble to some of the popular dessert ba-nana cultivars grown in the region.

The preliminary evaluation data indi-cate the potential of Big Ebanga andNjock kon for commercial cultivation inKerala. In view of the differences in theproduction potential of these cultivars,detailed studies on their performanceunder different input levels and man-agement practice are needed. They arepresently under multilocational evalua-tion in farmers fields. Popoulu, with aclose resemblance to Nendran, andYangambi km5, due to its acceptableyield and quality, combined with resis-tance to yellow Sigatoka, hold promisefor cultivation in the home gardens. ■

ReferencesJacob. 1952. Madras banana: a monograph. Superin-

tendent, Govt. Press, Madras.Stover R.H. & N.W. Simmonds. 1987. Banana (3rd

edition). Longman, London, United Kingdom.Daniells J. & N. Bryde. 1995. Semi-dwarf mutant of

Yangambi km5. InfoMusa 4(2): 16-17.

The author works at Kerala Agricultural University,Banana Research Station, Marakkal, Kannara, Thrissur680 652, India, e-mail: [email protected].

Table 2. Plant and bunch characters of banana introductions and indigenous cultivars.

Cultivar Plant Pseudostem No of functionnal Crop cycle Bunch weight No of hands No of fruits Pulp/peel Recovery

height (cm) girth (cm) leaves (days) (kg) ratio of chips (%)

Big Ebanga 281 53.2 13.5 335 14.3 5.1 44.2 3.3 34.7

Njock kon 250 76.3 12.5 426 25.0 8.7 125.6 3.2 30.0

Nyombe 400 70.5 10.3 480 32.0 10.2 150.3 3.0 29.0

Popoulu 262 52.0 11.0 314 9.5 6 51.0 4.2 -

Yangambi km5 226 51.5 12.0 320 13.5 9.0 132.0 4.0 -

Nendran 271 52.6 12.3 310 10.3 5.0 52.0 3.2 30.0

Myndoli 350 73.2 12.5 422 28.2 8.8 120.3 3.1 29.0


Rachel C. Sotto and Roel C. Rabara

The cultivated and edible bananasand plantains of the world areclosely related to and have, in

fact, originated from two wild species,one of which is Musa balbisiana Colla.M. balbisiana is a distinct species inthe genus Musa and is reported to benative to the Philippines where it is ofwidespread occurrence. Its wide range

of distribution may be attributed to itshigh vigour and apparently very high re-sistance to pests and diseases. However,due to lack of interest or lack of re-sources, the genetic diversity of M. bal-bisiana has not yet been studied inten-sively and no subspecies have yet beendescribed (Shepherd 1988). In the faceof rapid biodiversity loss of native plantspecies in the Philippines, there is anurgent need to estimate the geneticvariation and conserve the diversity of

Morphological diversity of Musabalbisiana Colla in the Philippines

Genetic resources Characterization

M. balbisiana germplasm in the coun-try. With these objectives in mind, thisresearch work was undertaken.

A two-year research project entitled,“Genetic Diversity and Morphotaxo-nomic Variation of Musa balbisianaColla in the Philippines”, and funded bythe Philippine Council for Agriculture,Forestry and Natural Resources Re-search and Development (PCARRD) wasthen started on July 15, 1998. So far,105 accessions from 24 provinces com-prising 10 geo-political regions of thecountry have been collected and are

being maintained at the Institute ofPlant Breeding’s (IPB) fruit genebank.Three hills were maintained per acces-sion totalling 306 hills. A duplicate col-lection is being established at the Bu-reau of Plant Industry – Davao NationalCrop Research and Development Center(BPI-DNCRDC), which also maintainsthe Southeast Asian Banana and Plan-tain Germplasm Resource Center. Of the105 accessions, 76 have been character-ized for the whole plant, pseudostem,leaf, inflorescence, bract, male flowerand fruit characters using the IPGRI De-

scriptors for Banana (Musa spp.)(IPGRI-INIBAP/CIRAD 1996). Initial ob-servations showed a wide diversity of M.balbisiana in terms of morphologicalcharacters. Bunch appearance rangedfrom lax to very compact. Colour of ma-ture green fruits ranged from green tolight green. Of interest was a silvery(waxy) form of M. balbisiana which wasnoted. In terms of fruit shape, a widevariation was observed ranging from el-lipsoid (Figure 1a) to roundish (Figure1b) with the fruit apex, acute to promi-nently bottle-necked (Figure 1c). Male


Figure 1. Variation in fruit shape of M. balbisiana: (a) ellipsoid; (b) roundish; (c) prominently bottle-necked.

Figure 2. Variation in male bud shape of M. balbisiana: (a) ellipsoid; (b) ovoid.

a

a b

b c

MusaNews

Asia and the PacificA new approach to triploid breeding inbanana in Taiwan

Most of the banana cultivars aretriploid. They are usually vigorous andcompletely sterile under natural condi-tion. Traditionally, there are two ap-proaches for triploid breeding in ba-nanas. One of them is to cross triploidplants with pollens from a diploid toproduce a tetraploid (3x X 2x ➔ 4x)and then backcross to the diploid par-ent to produce a secondary triploid (4x X 2x ➔ 3x) (Rowe and Richardson1975). Another approach is to generatean autotetraploid from a diploid plantusing colchicine treatment (2x ➔ 4x)and then cross to a diploid to producea triploid (4x X 2x ➔ 3x) (Bakry andHorry, 1994). Last year, the researchersof the National Taiwan University, DrC.T. Shii and Miss C.F. Liu used tissueculture technique and succeeded inproducing triploid plants from the en-dosperm of the developing seeds re-sulted from fertilization of diploids(Liu 1999, Liu and Shii 1999). This newtechnique opens the door of a simpleand rapid procedure to producetriploids in banana, i.e. 2x X 2x ➔ en-dosperm culture ➔ 3 x.

Another advantage of this approach isthat any diploid combination can beformed as long as the endosperm canbe obtained after pollination. Furtherinvestigation on the practical applica-tion of this method in banana breedingis being conducted.

ReferencesBakry F. & J.P. Horry. 1994. Musa breeding at

CIRAD-FLHOR. Pp 169-175 in The Improvementand testing of Musa: a Global Partnership. Pro-ceedings of the First Global Conference of the

International Musa testing Program (D. Jones,ed.), held at FHIA, Honduras, 27-30 April, 1994.INIBAP, Montpellier.

Liu C.F. 1999. Studies on regeneration capacity inendosperm tissue culture of diploid bananas(Musa spp.). Master thesis. The National TaiwanUniversity, Taipei. 72 pp (in Chinese with En-glish abstract).

Liu C.F. & C.T. Shii. 1999. Induction of embryogene-sis from the endosperm culture of diploid bana-nas. J. Chinese Soc. Of Hort. Sci. (Taiwan) 45:471 (Abstract in Chinese).

Rowe P.R. & D.L. Richardson. 1975. Breeding ba-nanas for disease resistance, fruit quality andyield. Bulletin 2. SIATSA. La Lima, Honduras, 41pp.

More information is available from C.Y. Tang,TBRI, PO Box 18, Chiuju, Pingtung 90403,Taiwan.

Banana plantation census in AustraliaThe results of a banana plantation cen-sus for the period to 30 June 2000 haverecently been published by Queens-land’s Banana Industry ProtectionBoard. There are 1013 properties listedin the census, representing 10,501hectares of plantations. Cavendish va-rieties occupy 9,680 hectares (92%) ofthis area. The most common diseasesrecorded were yellow Sigatoka (1013properties), leaf speckle (1013 proper-ties), Panama disease (162 properties)and bunchy top disease (89 proper-ties). Black Sigatoka, bacterial wiltand bract mosaic diseases were notfound.Further information is available from Mr N. Janetzki, Secretary, Banana IndustryProtection Board, c/o Department of PrimaryIndustry, GPO Box 46, Brisbane Q 4001, Australia.

The effects of airborne fluoride pollutionon bananas in ChinaA study was carried out on the causesof banana leaf marginal scorch on ba-nanas in Dongguan county in China.Leaf scorching has been recognised as


Figure 3. Variation in leaf characters of M. balbisiana: (a) straight petiolar canal with erect margins, inequilateral leaf base; (b) margins of petiolar canalcurved inward, equilateral leaf base.

bud shape was also variable rangingfrom ellipsoid (Figure 2a) to ovoid (Figure 2b) with majority of the acces-sions exhibiting an ellipsoid shape. Maleflower colour on the other hand, rangedfrom creamy white to variably tingedwith pink. Distinct variation in leaf char-acters were also noted especially withthe leaf petiolar canal which was ob-served to be either straight with erectmargins (Figure 3a) or with marginscurved inward (Figure 3b) but not en-closed or overlapping. Leaf base was ei-ther equilateral (Figure 3b) or inequilat-eral (Figure 3a). More variations wereobserved and these will be reported assoon as the characterization work iscompleted.

Both morphological characterizationand biochemical characterization usingisozymes are on-going. Molecular char-acterization using locus-specific mi-crosatellites or simple sequence re-peats (SSRs) need to be carried out tocomplement and further characterizethe variation observed in the PhilippineM. balbisiana germplasm collection. ■

ReferencesIPGRI-INIBAP/CIRAD. 1996. Descriptors for Ba-

nana (Musa spp.). International Plant GeneticResources Institute, Rome, Italy; InternationalNetwork for the Improvement of Banana andPlantain, Montpellier, France/Centre de coopé-ration internationale en recherche agronomiquepour le deéveloppement, Montpellier, France.

Shepherd K. 1988. Observations on Musa taxonomy:a note on Musa germplasm of the Philippines.Pp. 158-165 in Identification of Genetic Diversityin the Genus Musa: Proceedings of an Internatio-nal Workshop held at Los Ba∞os, Philippines, 5-10 September 1988 (R.L. Jarret, ed.). INIBAP,Montpellier, France.

The authors work at the Institute of Plant Breeding,College of Agriculture, University of the PhilippinesLos Baños, 4031 College, Laguna, Philippines

a b

a major constraint to production inthis area since 1987 and is thought tobe responsible for yield losses ofaround 20%. The study revealed thatthe cause of the leaf scorching was air-borne fluoride pollution, with the mainsource of the pollution being brick-fields and cement factories. It wasnoted that dwarf Cavendish was moresensitive to the pollution than plan-tains and other Cavendish varieties.More information is available from Zhang Hailanand Wu Dinyao, Tropical and Subtropical FruitResearch Lab, South China AgriculturalUniversity, Guangzhou 510642, China.

Studies on seeded bananas in Assam,IndiaIn the Northeast regions of India, twotypes of seeded bananas are commonlyused as baby foods. These bananas,known locally as ‘Bhimkal’ and ‘Athi-akal’, are very hardy, resistant to pests,diseases and drought and are highyielding. Bhimkal in particular is a richsource of energy (114.4 kcal/100g).Studies on the growth, developmentand genome of these two bananas werecarried out at Assam Agricultural Uni-versity. On the basis of morphologicaltaxonomic characterisation, bothBhimkal and Athiakal were found toclosely resemble Musa balbisiana. Ac-cording to the scoring system of Sim-monds and Shepherd (1955), no“acuminata” characteristics were iden-tified and the scores obtained indicatedboth bananas had pure ‘balbisiana’genomes. Chromosome counts werecarried out on cells from root tip andmale flowers. The number of chromo-somes was recorded at metaphase I as22 in both bananas, in 11 pairs. Fromthis study, it could be clearly seen thatboth Bhimkal and Athiakal are diploidbananas.

ReferenceSimmonds N. W. & K. Shepherd. 1955. The taxo-

nomy and origins of the cultivated bananas. J.Linn. Soc. Bot. 58: 302-312.

Further information is available from U. Kotoky,Associate Professor, Department of Horticulture,faculty of Agriculture, Assam AgriculturalUniversity, Jorhat, Assam, India.

Banana bunchy top disease – a majorthreat to hill banana cultivation in thelower palani hills of Tamil Nadu, IndiaIn India, banana crops occupy an areaof about four million ha, producing 4.0to 28.7 tonnes/ha of fruit. The hill ba-nana, sirumalai/vellavazhai, is mainlygrown between 800 and 1400 masl as arain-fed crop in Tamil Nadu, especiallyin the lower palani hills, and in Kerala.An area of 15 000 ha is planted with thehill banana, producing 7 tonnes/ha andRs 26.5 million a year (Rs1000 =US$23).

Banana bunchy top disease (BBTD)causes serious yield losses in hill ba-nana production. The perennial natureof the crop, continuous presence of thepathogen and the mild weather, favour-ing the aphid vector, all contribute tothe high incidence of BBTD. A surveyinvestigating the economic lossescaused by the disease at different alti-tudes discovered that BBTD causes adecrease in economic returns of 60% at1200 masl and 50% at 1000 masl. Above1200 masl and below 400 masl thelosses were less because higher humid-ity and higher temperatures, respec-tively, provided less favourable condi-tions for the multiplication of theaphid vector.

High incidence of BBTD is resultingin severe economic losses over a largepart of the area where hill bananas arecultivated. It is essential that indexingof suckers (using either ELISA or PCRtechniques) is carried out to detect thepresence of BBTD at an early stage anddisease-free suckers are supplied inorder to lessen the impact of the dis-ease and revive hill banana cultivationand the farming economy.Further information is available from K.Manickam, T. Ganapathy and S. Doraiswamy,Department of Plant Pathology, Centre for PlantProtection Studies, Tamil Nadu AgriculturalUniversity, Coimbatore 641 003, India.

West AfricaA new appropriate technology for rapidmultiplication of plantain suckers inGhanaPlantains and bananas are majorstarchy staples for Ghanaians. Theyare of great socioeconomic and nutri-tional importance and also generateconsiderable rural income and employ-ment.

The major production constraints in-clude pests (weevils and nematodes)and diseases, especially black Sigatoka,lack of planting materials and decliningsoil fertility.

To address the disease problems, newresistant/tolerant tetraploid hybrids ofbanana and plantain were introduced.To improve the planting material situa-tion, a rapid multiplication techniquecalled the split-corm technique was de-veloped. This technique could produceabout 8-10 sets from a medium-sizecorm and would be ready for trans-planting after about 8-12 weeks.

A new technique, which can generatemore suckers within a shorter period,has been developed.The procedure includes:1. Create a wooden column about 1.2 m

by any convenient length, 30 cm talland fill with sawdust (the columncould be created as a trench andfilled with sawdust).

2. Uproot the corm to be used and trimoff roots and peel to remove nema-todes and weevils.

3. Split corm into two or four parts de-pending on the size of the corm.

4. Treat the corm pieces with a solutionof fungicide e.g. 1% Benlate.

5. Air-dry the treated corms for 24hours under shade.

6. Plant the corm pieces 15 cm deepinto the sawdust with the cut surfacedownward (preferably near a watersource to facilitate irrigation).

7. Build a shed over the column withpalm frond or a polyethylene sheet tomaintain a humid condition.

8. Irrigate daily.9. Sprouting starts after 8 days.

Excise the new shoots from themother corm when two green leavesappear and plant in a 7 x 9 cm blackpolybag filled with 7 parts loamy soil,2 parts river sand and 1 part well-de-composed poultry manure. Hardeningtakes one month, after which theplants can be planted in the field.Continue to irrigate the column andremove shoots as they appear.The mother corm will continue toproduce healthy shoots for about 5weeks.

Advantages:1. Suckers are produced close to the

farm which reduces the cost of trans-port.

2. Disease and pest-free planting mate-rials are produced.

3. Several planting materials are pro-duced within a very short time.

4. All the available buds on the cormare able to express themselves (someof the buds may have been lost by thesplit corm technique).

5. True-to-type materials are produced.Further information is available from B.M.Dzomeku, B. Banful, D.K. Yeboah and S.K.Darkey, Crops Research Institute, PO Box 3785,Kumasi, Ghana

Latin America and the CaribbeanBreeding for the resistance to Panamadisease in banana clones ‘Manzano’ (AAB)and ‘Gros Michel’(AAA) through tissueculture and in vitro mutagenesisDuring the past years, in vitro culturecombined with induction and inducedsomatic mutation breeding becamemore effective due to the developmentaccomplished in genetic breeding viabiotechnological techniques. This pro-ject began with the aim to breed, on alaboratory level and then in the field,resistant or tolerant to Panama disease(Fusarium oxysporum var. cubense),races 1 and 2, somaclones from the sus-ceptible clones ‘Manzano’(AAB) and‘Gros Michel’(AAA). Vitroplants of bothclones first were initiated from thebuds and induced to form multiple


10.

11.

12.


buds, then, they were treated withphysical mutagenic agents (Gammarays), Co60 source. The inoculationswere carried out with different fungusisolates from the INIFAT – 1 strain dur-ing four in vitro development cycleswith a 3 x 105 spores/ml solution during30 minutes, which resulted to be morepathogenic in previous studies. Oncethe process concluded, the vitroplantswere planted in beds containing or-ganic soil contaminated with the re-mains of the plants infected withFusarium oxysporum. After 60 days,the vitroplants that has not presentedleaf yellowing symptoms, were reinocu-lated with a spore solution from thesame strain puncturing the base of the

pseudostem. After 6 months, symptom-less vitroplants were transplanted inthe field infected with pathogen inorder to evaluate the disease incidence.42 somaclones were selected whichwere again multiplied in vitro until 100individuals were obtained from eachone (clonal line), evaluating once moretheir behavior to the disease both inbeds and in the field. Finally, therewere selected nine somaclones of theclone ‘Gros Michel’, which presentedinfection signs in the field lower than30%. In the derived material of the‘Manzano’ clone, all the selections wereclassified susceptible after the firstcycle in the clonal study. The resistantsomaclones with favorable agronomic

characters were in vitro micropropa-gated and their yields are under studyat this time.

Information provided by I. Bermúdez, P.Orellana, N. Veitía, C. Romero, J. Clavelo, L.García and M. Acosta, Instituto de Biotecnologíade las Plantas, Universidad Central de las Villas,Carretera a Camajuaní Km 5 1/2, UniversidadCentral “Martha Abreu” de las Villas, SantaClara, Villa Clara, Cuba (e-mail:[email protected]; Tel.: 81360 – 81693) yL. Herrera I., Facultad de Ciencias Agropecuarias,UCLV, Santa Clara, Villa Clara, Cuba.

Pauline Osiro Omoaka

Satisfactory objective methods to evalu-ate banana fruit (Musa spp.) qualityfrom harvesting, ripening to retailingare still lacking. An objective methodfor banana quality evaluation is crucialto the success of the market industryand consumer health.

The feasibility of using electrical im-pedance spectroscopy to evaluatepostharvest banana quality and ripeningis presented in this dissertation. Lowfrequency resistance and “Py” increasedwith ripeness and “low” values (depend-ing on peel colour) mostly correlatedwith abnormal pulp condition. Electri-cal impedance technique has the poten-tial of relating internal quality and peelcolour during banana ripening.

Banana quality at any given time isdefined by interrelated basic parame-ters. Combinations of internal and ex-ternal quality parameters confer an ex-pected degree of excellence. However,it is difficult to define the exact charac-teristics to make the distinction.

The application of appropriatepostharvest techniques extended

‘green-life’, ripening-shelflife periodsand maintained quality but did not im-prove after-harvest quality. Harvest ma-turity is therefore essential for desiredbanana quality. Banana handling, stor-age conditions and operational prac-tices influence changes in the pulp,peel and shelflife. However, changeswere completely dependent on fruit’sphysiology and biochemistry.

Physiochemical changes in bananassubjected to various handling practicesand environmental conditions weremonitored. Ethylene production, respi-ration rate, peel colour, soluble solidscontent, pulp firmness and electricalimpedance were potential indicators(initiator in the case of ethylene) forripening, quality and storage life.

Examined changes in bananas in-duced with ethylene indicate the signif-icant effect of temperature on ripening.However, significant transient delay inpulp softening and peel discolorationoccurred in ‘natural’ ripened fruits. Pa-rameters such as 1-aminocyclopropane-1-carboxylic acid (ACC), chlorophyllcontent and pulp firmness jointly lendscredibility to observed changes. Tem-perature along with ethylene induction

sometimes led to uncontrolled ripening.Exogenous ethylene induced autocat-alytic ethylene production. Within anacceptable temperature range (14-18°C) and relative humidity (85-95%)bananas ripened in 4-8 days.

Cold damage symptoms occurred inbananas stored below 12°C. The degreeof damage at a certain temperature de-pends on the exposure time. Symptomsbecame visible upon transfer tofavourable temperatures or during sub-sequent ripening. The registration ofonly the pulp temperature was notenough to explain the observed finalfruit quality.

Controlled hot air treatment of greenbananas induced changes associatedwith banana ripening. The informationgenerated will no doubt help in extend-ing the use of hot air treatment as analternative to ethylene induction for ba-nana ripening.

The use of peel colour as a single in-dicator of ripening is erroneous due todifferences dependent on the time andplace and the evaluator. The peelcolour attribute can better be mea-sured objectively as a forward step inquality evaluation. ■

Postharvest physiology, ripening and qualityevaluation in banana (Musa spp.) fruitsPhD Thesis submitted in August 2000 at the Faculty of Agricultural and Applied Biological Sciences, Katholieke Universiteit Leuven (KUL), Belgium.

Thesis

Alternatively, hard copies should besent to M. Daneel, ARC-Institute forTropical and Subtropical Crops, PrivateBag X11208, NELSPRUIT 1200, SouthAfrica.Important datesAbstract submitted: 15 January 2001Last date for registration: 15 January 2001Acknowledgement of receipt of abstract: 28 February 2001Congress AddressMieke DaneelNSSA Organizing CommitteeARC-Institute for Tropical and Subtropical CropsPrivate Bag X11208Nelspruit 1200South AfricaTel: (27) 13 7532071Fax: (27) 13 7523854E-mail: [email protected] details and registration form areavailable from: http://www.inibap.org/actualites/nssa_eng.htm

IVth International scientificseminar of plant health (2nd announcement)Varadero, Cuba, 11–15 June 2001The Centro Nacional de SanidadAgropecuaria (CENSA) and the Insti-tuto de Investigaciones de SanidadVegetal (INISAV) announce the IVth In-ternational scientific seminar of planthealth and several other scientificmeetings that will take place in Va-radero, Cuba, from 11 to 15 June 2001at the International Conventions Cen-ter “Plaza América”.

In this forum will be discussed theproblems and more recent results, aswell as the tendencies of the planthealth and plant protection for the newmillennium.

Eight scientific meetings will takeplace during the event and amongthem, the International workshop onpests and diseases in banana: currentsituation and challenges for the newcentury.

Scientists, specialists and studentslinked to the plant health and plantprotection are invited to submit thesummaries of the papers to be pre-sented as posters or oral presentations.A copy of the summaries should be sentbefore March 30, 2001 by e-mail at: [email protected] with copy to thePresident of local organizing committeeof the specific meeting that you want toparticipate. Regarding the workshop onpests and diseases in banana, pleasecontact the coordinator, Dr Luis PérezVicente at one of the following e-mail


Ruth Stoffelen

Screening of bananas (Musa spp.)for resistance to root-lesion androot-knot nematode species was

under study. The work was conducted inthree steps: (i) standardization of thescreening procedure, (ii) screening of68 Musa varieties for resistance to ba-nana nematodes during the early vege-tative growth stage and (iii) evaluationof three important aspects related toscreening experiments: variability in re-productive fitness of nematode popula-tions, variability in root architecture ofbanana varieties and the interactionbetween nematode reproduction androot development.

In a first step, a screening procedurefor evaluation of resistance of bananasto root-lesion and root-knot nematodespecies during the early vegetativegrowth stage was developed. In addi-tion, the screening procedure wasadapted for screening under in vitroconditions. During the second step,68 Eumusa and Australimusa bananaswere evaluated for resistance toRadopholus similis, Pratylenchus cof-feae and Meloidogyne spp. in an earlyvegetative growth stage. Two newsources of resistance to R. similis werefound in the Australimusa section(Fe’i bananas). No sources of resistanceto P. coffeae and Meloidogyne spp. wereidentified.

In the third step, nematode reproduc-tion, banana root development andtheir interaction was studied. Variabil-ity in reproductive fitness on carrotdiscs was observed for four R. similispopulations, but not for three P. coffeaepopulations. Diversity in root architec-ture (lengths of all root types) was ob-served for 11 banana varieties grown inhydroponics. Finally, the interaction be-tween banana root growth and nema-tode reproduction was studied during4 months. Root growth was a dynamicprocess consisting of a lag phase, fol-lowed by three flushes of root emer-gence. Nematodes reproduced in all

root types and reproduction dependedon the presence of fresh roots. Evalua-tion of banana root growth and nema-tode reproduction during a 1-year studyrevealed that environmental effects in-fluenced both parameters.

The screening procedure can be opti-mized by (i) using the same nematodepopulation to avoid the influence ofvariability in reproductive fitness, (ii)including a susceptible reference ba-nana cultivar so that environmental ef-fects can be detected and (iii) adaptingthe inoculation and analysis to the ba-nana root growth. ■

Announcements

15th Nematological congress onIntegrated nematode control inthe new milleniumSkukuza, South Africa, 20-24 May 2001The Nematological Society of SouthernAfrica (NSSA) is presenting the 15th

Nematological Congress at Skukuza,Kruger National Park, South Africafrom 20 to 24 May 2001. The congresswill include papers and poster sessions.Workshops on new or interesting topicscan be organized. A visit to the bananagrowing areas and a PROMUSA meetingfrom 24 to 26 May 2001 will follow thecongress. The meeting will be held atCybele Guest House, Kiepersol,Mpumalanga, South Africa.

The organizing committee invites youto present one or more papers orposters on any aspect of the science ofnematology at the symposium. Contri-butions should preferably be in English.

Posters (110 cm x 90 cm) will be oncontinuous display for the duration ofthe symposium. A 5-minute presenta-tion will be allowed per poster to dis-cuss the contents, with 5 more minutesfor discussion.

Abstracts should be in English andnot exceed 250 words. They will be pub-lished in African Plant Protection. Ab-stracts should preferably be sent by e-mail to [email protected] as anattached file in the latest possible ver-sions of Microsoft Word or Word Perfect.

Early screening of Eumusaand Australimusa bananas against root-lesion and root-knot nematodesPhD Thesis submitted in March 2000 at the Faculty of Agricultural and Applied Biological Sciences, Katholieke Universiteit Leuven (KUL), Belgium.

addresses: [email protected]; [email protected]; [email protected] by mail at:

INISAVPO Box 634, 11300, PlayaLa Habana, CubaFax: (53 7) 332501

If you require more information or haveany question about a particular aspect,please contact:

Dr Esther Lilia PeraltaPlant Protection Division,CENSA, PO Box. 10, San José de lasLajasHabanaTel: (53 64) 63014, Ext. 45Fax: (53 64) 63897E-mail: [email protected]

More information and registration formare also available at:

http://www2.cuba.cu/ciencia/inisav/http://www.inibap.org/actualites/

varadero_eng.htm

INIBAP News

Events in Thailand Between 4th and 12th November, a seriesof meetings and exhibitions took placein Bangkok, Thailand, as part of aunique International Banana Sympo-sium coorganized by INIBAP, the De-partment of Agricultural Extension andNaresuan University. Her Royal High-ness Maha Chakri Sirindhorn, Princessof Thailand, opened the technical ses-sions on 6th November after a weekendof displays and competitions to identifythe best dessert banana, best cookingbanana and best banana products.Amongst those exhibiting their workand products in Queen Sirikit’s NationalConvention Center were Thailand’s topagricultural institutes and industrialcompanies, as well as organizationsfrom elsewhere in the world. INIBAPparticipated in the exhibition, using dis-play boards specially made for the occa-sion. An opportunity was also provided toshow the multimedia CD-ROM adaptedfrom the Banana Brochure and newlytranslated into English. The INIBAPTransit Centre and ASPNET also hadpopular displays, and each member ofASPNET brought individual posters rep-resenting the research and developmentoccurring in their country.

Three days of meetings followed, withsessions running concurrently. A Tech-nology Transfer Session took place forthe benefit of over 300 scientists andtechnicians from the region. Presenta-tions were given on the advance and po-tential of new technologies on the useof tissue culture in cropping, virus man-agement, breeding, and biotechnology.Representatives from China, the Philip-pines, Malaysia and Australia gave pre-


Banana exhibition at Queen Sirikit’s National Convention Center.

INIBAP products proved popular during the symposium.

a, b & c. Winning entries in the banana competition were on display. Moto Ebanga from CRBP (center)was winner of the “most original banana prize”.

I n t e r n a t i o n a l B a n

a b


Banana products enter for the competition.

Thai lady demonstrates production of bananasweets.

a n a S y m p o s i u m i n T h a i l a n d

c

sentations on the banana productionand trade in their respective countries.

The impressive scale of the events inThailand provided a magnificent con-text to celebrate and reflect upon the15 eventful years since INIBAP waslaunched.

Tenth meeting of the Regional AdvisoryCommittee of INIBAP-ASPNETThe 10th meeting of the ASPNET Steer-ing Committee took place on 10-11 No-vember in Bangkok, Thailand. The con-ference was hosted by Prof. SujinJinahyon, President of Naresuan Uni-

versity and Dr Ananta Dalodom, DirectorGeneral of the Department of Agricul-ture (DOA/Thailand). Dr Emile Frisonwas Guest of Honor. Special guestsfrom QUT, IITA, KUL, and CIRAD pre-sented technical papers on Advancesof Biotechnology R & D in Musa, Appli-


INIBAP’s 15 years anniversary celebrated in Montpellier

On the occasion of its 15th anniversary, INIBAP organised a half-day seminar on “Bananas and food security” which took place at Agropolis International,Montpellier, on 15th December.The speakers included Dr Emil Javier, Chairman of the Technical Advisory Committee of CGIAR, Dr Gilles Saint-Martin, Excecutive Secretary of the Comitéinterministériel pour la recherche agricole internationale, Dr Jacky Ganry, Deputy-Director, Cirad-Flhor, Dr Henri Rouillé d’Orfeuil, Vice-President of theGlobal Forum for Agricultural Research (GFAR), Dr Louis Thaler, Professor Emeritus at the University of Montpellier II, Dr Michel de Nucé de la Mothe,President of Agropolis and Dr Emile Frison, Director of INIBAP.Participants unanimously agreed that INIBAP’s innovative modus operandi has proved to be a real success. Moreover, the networking system, which it haseffectively implemented over the last 15 years, is now being used as a model for other sectors in international agricultural research.

Jean-Vincent Escalant led a workshop for children on banana diversity at the Agropolis Museum thesame day.

Jean Champion, well known to all in the bananaresearch community, attended the INIBAPseminar on 14 December with his wife Arlette.

cation of Biotechnology in Banana Vi-rology, Status of Banana and PlantainBreeding, Recent Developments inMusa Nematology Research, Study ofMycosphaerella fijiensis, Populationsand Partial Resistance of Bananas andStatus of Banana Weevil R & D.

Dr Agustin Molina, Regional Coordi-nator for Asia and the Pacific pre-sented the highlights of the 10th yearof ASPNET operations. Updates wereprovided on Banana R & D Activities inthe Philippines, Nematology Researchin Vietnam the ICAR/NRCB-INIBAPProject in India, the Evaluation andAdoption of the INIBAP hybrids at theSecretariat of the Pacific Community,Varietal Evaluation and Disease Man-agement in Sri Lanka and the news ofa promising clone in Taiwan which at-tracted much interest.

IMTP and NEP activities, the pro-posed National Repository Multiplica-tion Distribution Center, the MusaBreeding Programme and the variousactivities and collaborations in ASP-NET were discussed in the PlanningSession. INIBAP staff, Dr Escalant andMs Sharrock discussed with the Com-mittee the two classifications of in-volvement in IMTP III: Performanceevaluation sites (minimum require-ment of 10 accessions) and In-depthsites (full spectrum of materials). Apreliminary survey was carried out onthe involvement of the various coun-tries represented at the meeting. Theparticipation of the private sector intrials was also considered. The possi-bility of incorporating an IMTP workinggroup into PROMUSA was also broughtup. A workshop may be conducted in order to standardize formats anddata-gathering.

Dr Molina presented information onthe proposed National Repository, Mul-tiplication, and Distribution Center.According to the plan, the nationalgovernment would assign an institu-tion responsible for acquisition of ma-terials from ITC, multiplication anddistribution within the country. Somemembers said that such a set-up is al-ready existing in their country and thatit is multiplication and distributionwhich requires enhancing. Fundingmay be sought for countries who needassistance in this area.

An update on the status of RISBAPwas presented by Ms Roa. Australia,Philippines, Sri Lanka, and Taiwan areactive contributors to the database.Special mention was given to Australiafor their campaign to raise awarenessof the INIBAP databases. It was alsoreported that an LOA with Malaysia ex-ists to provide assistance in data gath-ering.

Finally, clarification was requestedon the responsibilities of the membersof the steering committee. After somedeliberation, it was agreed that a smallcommittee be formed to come up witha list which will be circulated for com-ments and then submitted to the re-gional coordinator.

During the meeting, Prof. Det Wat-tanachaiyingcharoen was electedChairman of ASPNET steering commit-tee, replacing Dr Chen Houbin of theSouth China Agricultural University(SCAU), who has served as Chair sinceNovember 1999. Prof. Wattanachaiy-ingcharoen will serve as Chair untilthe 11th ASPNET meeting which willbe held in Sri Lanka in August 2001.

The Pisang Raja awardsIn recognition of 21 years of outstand-ing accomplishment in banana breed-ing and biotechnology, and also for hisprofound contribution to INIBAP andASPNET, Rony Swennen received thePisang Raja award at the meeting ofthe ASPNET Steering Committee. Like-wise the award was given to Ben-chamas Silayoi for her immense contri-bution to banana research anddevelopment, including the authoringof over 20 technical articles and booksin the area of banana taxonomy, genet-ics, and breeding, and her long associ-ation with INIBAP and its activitiessince 1986.

Addressing banana virus diseasemanagement in BangladeshBanana diseases are a major constraintof banana production in Bangladesh.Viruses, such as BBTV, BBrMV, BSV andCMV are a particular concern. In an effort to address the problem INIBAPsponsored a seminar-workshop on ba-nana diseases and a virus-indexingtraining course. The events took placeat the Horticulture Research Centre,Bangladesh Agricultural Research Institute (HRC-BARI), Joydebpur,Bangladesh, in September. They repre-sent the third in a series of seminar-workshop and training sessions orga-nized by ASPNET, the other two havingtaken place in the Philippines and SriLanka.

A total of 52 participants attendedthe workshop with speakers comingfrom Taiwan, the Philippines andBangladesh. The nature, epidemiologyand management of major banana pestsand diseases were discussed. Emphasiswas made of the successful use of virus-indexed tissue culture in the manage-ment of virus diseases. The DirectorGeneral of BARI, Dr M.A. Razzque, ex-pressed his appreciation to INIBAP,ASPNET and Prof. Hong-Ji Su of the Na-

tional Taiwan University, for the theirassistance in alleviating pest and dis-ease problems in Bangladesh. He de-clared that a virus management pro-gramme will be implemented. Hands-ontraining, conducted by Prof. Hong-Ji Su,was provided for nine BARI scientificofficers. Two indexing procedures, theELISA and PCR-based techniques weretaught.

Novel approaches to theimprovement of bananaproduction in Eastern Africa Over the past two decades bananayields in East Africa have been declin-ing. The most probable causes are theincreasing load of pests and diseases(esp. black Sigatoka, nematodes andweevils) and the deteriorating naturalresource base. The effort to produce im-proved varieties with locally acceptablepost-harvest characteristics using con-ventional approaches is constrained bythe high level of sterility of most EastAfrican Highland banana (EAHB) vari-eties. However genetic engineeringtechnologies offer an alternative routefor improving yields.

The Ugandan government is funding aproject on “Novel Approaches to the im-provement of banana production inEastern Africa—the application ofbiotechnological methodologies” astheir allocation to the CGIAR. It in-volves the collaboration of IITA, NARO,Makerere University, CIRAD, KUL andINIBAP, which will coordinate and su-pervise.

This project has a specific focus onimproving the production of existing ba-nana varieties by enhancing their resis-tance to fungal pathogens, nematodesand weevils, whilst maintaining theirdesirable post-harvest/culinary quali-ties. Complementary approaches will beused. In the case of black Sigatoka andnematode resistance, known genes cod-ing for anti-fungal proteins and geneswith a high potential to control nema-todes will be introduced into EAHB cul-tivars by genetic transformation using awide range of gene constructs. Themost effective genes will be identifiedfirst in transgenic model plants andsubsequently during field testing. Multi-ple resistance will be achieved by genepyramiding.

In the case of weevil resistance, twoapproaches will be followed. In collabo-ration with IITA and NARO, the geneticmechanisms underlying weevil resis-tance in EAHB will be studied and wee-vil-resistance genes and genetic mark-ers identified. At the same time, withCIRAD’s collaboration, toxins from thenew strains of Bt, which have an effecton Coleoptera, will be tested for their



efficacy in controlling weevils. Giventhe successful outcome of this phase ofresearch, further funding will be soughtto transfer weevil resistance into EAHB.

Developing a centre of biotechnologycompetence and upgrading existingmolecular biology facilities in Uganda

will form an essential element to theproject. Ugandan scientists will receivetraining and their participation in in-ternational meetings and workshopswill be supported.

A planning meeting and technicalworkshop took place in September in

Uganda, bringing together all partnersin the project. To develop plans for pro-ject implementation, four workinggroups on cell suspensions and tissue

Participants in the project on "Novel approaches to the improvement of banana production in EasternAfrica – the application of biotechnological methodologies".

Field visit in Uganda.

All you want to know about

BANANASon a multimedia

CD-ROMThis multimedia CD-ROM on bananashas been produced as a joint effort ofthe International Network for theImprovement of Bananas and Plantain(INIBAP) and the Centre de coopérationinternationale en recherche agronomiquepour le développement (CIRAD).

Organized in seven chapters, this very attractive CD-ROM presents information on all the aspects of the croplavishly illustrated with films, photographs, maps, comics, etc.

Demonstrated during the EXPO 2000 in Hanover, Germany (August 2000) and during the Banana and Pineapple professional meeting organized by CIRAD-FLHOR in Montpellier, France (September 2000).

Limited edition.Buy it now hot from thepress !

Rates :Up to 50 copies 15 US $ per copyFrom 51 to 200 copies 10 US $ per copyMore than 200 copies 8 US $ per copyPrice for one copy 25 US $

Please return your orderand payment to: INIBAPParc Scientifique Agropolis II, 34 397 Montpellier Cedex 5, FranceTel.: 33 - (0)4 67 61 13 02 Fax: 33 - (0)4 67 61 03 34Email: [email protected]

• The world’s largest herb

• The much-travelled

banana

• Banana – a basic food

• The industrial chain of

dessert banana

• Watch that plant grow!

• Protecting the banana

and its future

• Banana as veg or

as dessert?

culture, molecular research,germplasm evaluation, and weevil re-search were formed. Each produced adetailed action plan for their activity,clearly identifying the responsibilitiesof each partner. Visits were made to the biotechnology laboratories ofMakerere University, the NARO stationat Kawanda and to IITA’s station at Na-mulonge to review the available facili-ties. Recruitment process is now inmotion, Ph.D students to work on theproject are being identified and plant-ing has started in the field. By January2001 the project will be fully opera-tional.

INIBAP web siteThe traffic on the INIBAP web site hasalmost doubled since June. Nearly 100visits are made daily, each taking anaverage of more than three minutes onthe site. The databases and publica-tions are amongst the most popularparts of the web site. Shortly to belaunched are new sites for the regionalnetworks, MUSACO in West and Cen-tral Africa, BARNESA in Eastern andSouthern Africa, MUSALAC in LatinAmerica and the Caribbean and ASPNETin Asia and the Pacific. These will include more detailed information onthe activities, objectives and make upof the networks, as well as statisticshighlighting the importance of bananaand plantain in these areas. It is nowpossible to download from the web thelast INFOMUSA (Vol. 9, 1), proceed-ings of the meeting on “Bananas andfood security”, “Organic/environmen-tally friendly banana production”(Spanish version) and “Organic ba-nanas 2000: Towards an organic ba-nana initiative in the Caribbean”. Alsothe one-off publications of Paul Allen’scatalogue of wild and cultivated ba-nanas and the results of Phase II ofIMTP, “Evaluating bananas: a globalpartnership”, are available. Finally, theINIBAP genebank web site has takenon the INIBAP look and can be ac-cessed at http://www.agr.kuleuven.ac.be/dtp/tro/itc.htm.

Joint initiative between IITA and INIBAPThe two Future Harvest centres carry-ing out Musa research and develop-ment (IITA and IPGRI, through INIBAP)recently decided to integrate theirMusa-related activities in Africa. Theagreement to establish a joint pro-gramme for Musa in Africa was final-ized at a meeting held in Uganda inSeptember 2000.

Although IITA and INIBAP were al-ready working closely together inAfrica, they believed that their comple-

mentary programmes should be com-bined into a single, well-focused re-search effort. It was felt that in thisway, the impact of their programmes onimproving smallholder production ofMusa in Africa would be maximized.The new joint programme will be imple-mented in the framework of the twosub-regional NARS-led banana researchnetworks—BARNESA operating underASARECA, and MUSACO operatingunder WECARD/CORAF.

Strategic planningAnnual programme planning will becarried out on the occasion of the BAR-NESA and MUSACO Steering Commit-tee meetings. These will provide aforum for the stakeholders to discussthe full research agenda and all issuesrelated to Musa in each sub-region.These meetings will provide an opportu-nity for priorities to be set and for theroles and responsibilities of the variousplayers in the research agenda to beclearly identified.

Germplasm conservationIITA and INIBAP will take on joint re-sponsibility for ensuring the long-termconservation of Musa germplasm ofAfrican origin. This will include the des-ignation of germplasm to the ‘in trust’collection held under the auspices ofFAO, ensuring the safety duplication ofall such conserved germplasm and mak-ing information on germplasm availablethrough the SINGER database.

Germplasm evaluationIn the area of germplasm evaluation,IITA and INIBAP have clearly comple-mentary roles. Thus IITA will continueto focus on early evaluation of breedinglines in multilocational trials, while IN-IBAP will focus on more down-streamevaluation in the framework of the In-ternational Musa Testing Programme(IMTP).

InformationThe MusAfrica newsletter, previouslypublished by IITA, will become a jointIITA-INIBAP publication. The newslet-ter will continue to be a forum for mem-bers of the regional networks to ex-change information on Musa researchin the region. Furthermore, activitiescarried out in the framework of thejoint programme will be reported byboth INIBAP and IITA in their respec-tive Annual Reports.

Public awarenessINIBAP and IITA will join forces in rais-ing the awareness of policy makers andthe public, which it is hoped will lead tothe allocation of greater resources to

Musa research and development in theregion.

Staff at INIBAPAlberto VilarinhosIn the framework of the AdvancedPlatform of Agropolis in Montpellier, a

joint project be-tween INIBAPand CIRAD hasbeen initiatedwith fundingfrom the FrenchGovernment. Al-berto Vilarinhos,a scientist withexperience inmolecular tech-niques and the

genetics of banana from EMBRAPA inBrazil, will carry out the research overfour years as part of his Ph.D. Entitledthe “Mapping of the Musa acuminatatranslocation break points throughmolecular cytogenetics”, the projectaims to use new methods developed foranimals and also wheat and rye, toidentify the points where segments ofDNA, known as translocations, breakoff in the chromosomes. This will helpanswer questions on segregation pat-terns and facilitate genetic mappingand ultimately banana breeding. Al-berto has moved to France with hisfamily and started work in September.

Gaston BoussouGaston Boussou has taken up a tempo-rary position as MGIS database assis-

tant. He will beupdating theMGIS database inpreparation forthe publication ofthe second Musa-logue. He comesto INIBAP with amaster degree ininformation anddocumentationfrom the Univer-

sity of Montpellier, as well as variousqualifications in mapping and watermanagement and quality, and also biol-ogy. His previous experience has in-cluded work with the Agritrop databaseat CIRAD and also supplying biblio-graphic information for MUSALIT, alsoat CIRAD.

Stijn MessiaenStijn Messiaen has been working onsecondment from INIBAP at the Ny-ombe, Cameroon-based Centre derecherches régionales sur bananierset plantains (CRBP) since July 1998as a Vlaamse Vereniging voor Ontwik-kelingssamenwerking en Technische


Bijstand (VVOB) Associate Expert inentomology. VVOB is the Belgian(Flemish) technical cooperationagency. For two years Stijn made im-portant contributions to the develop-ment of integrated strategies to con-trol weevils (Cosmopolites sordidus)an economically important pest of ba-nana and plantain world-wide. Stijn’swork encompassed the use of genetic(host plant resistance), bio-insectici-dal (seed cake of neem [Azadirachtaindica], household ash and leaves ofTithonia incongita), microbial (Beau-veria bassiana), physical (trapping)and chemical methods. As part of thedevelopment of techniques of controlof weevils, Stijn conducted research tounderstand the life cycle and the be-haviour of the pest. Stijn has alreadypublished some of the substantial re-sults he obtained in scientific journalsand has many more manuscripts in thepipeline. In addition to his research,Stijn also participated in the trainingof university students on attachment atCRBP. Dr Roger Fogain supervisedStijn’s work at CRBP with inputs fromDr Cliff Gold of IITA, Kampala, Ugandaand Dr Dirk De Waele of KUL, Belgium.We wish Stijn success in his plans topursue a PhD degree at KUL in hishome country Belgium.

Julie SchurgersJulie Schurgers worked as an INIBAPintern at CRBP from November 1998 toJuly 2000. She was part of the team thatinitiated research on cell suspensionsand somatic embryogenesis at CRBP.For a time Julie coordinated responsesto requests for rooted plantlets and pro-liferating cultures from the INIBAP-mandated regional germplasm distribu-tion centre for West and Central Africa.Julie spent her last 7 months studyingtechniques of employing molecularmarkers to breed for resistance to ne-matodes at the Laboratory of tropicalcrop husbandry at KUL, Belgium underProf. Dirk De Waele. We wish her well inher future endeavours back home inBelgium.

Books, etc…

Banana cultivar names andsynonyms in Southeast AsiaR.V. Valmayor, S.H. Jamaluddin, B. Silayoi,S. Kusumo, L.D. Danh, O.C. Pascua andR.R.C. EspinoISBN: 971-91751-2-5The Southeast Asia region harbours thegreatest wealth of banana diversity,both in wild and cultivated forms. Thisincludes some of the rarest varieties inthe world. But how to classify them and

even what to call them has always beena complicated issue. In many cases, thesame varieties have been given differ-ent names in different areas and thelikewise the same name has been givento different varieties.

In September 1999 a landmark meet-ing of the curators of national bananagermplasm collections took place in thePhilippines. They resolved the names ofnearly 300 banana varieties and agreedon a classification system, followingthat of Cheeseman and the Interna-tional Code of Nomenclature for Culti-vated Plants. This 24-page booklet pro-vides the background on thenomenclature and classification of ba-nanas in the region and the final listingof variety names and synonyms agreedat the meeting in Southeast Asia. An es-sential companion for collectors, cura-tors, breeders and researchers aroundthe world!

Available from the INIBAP regionaloffice for Asia and the Pacific, c/o IRRICollaborators Center, College, Laguna4031, Philippines.

Advancing banana and plantain R & D in Asia and the PacificProceedings of the 9th INIBAP-ASPNETRegional Advisory Committee meetingheld at South China AgriculturalUniversity, Guangzhou, China, 2-5 November 1999Edited by A.B. Molina and V.N. RoaISBN: 971-91751-3-3For the first time the proceedings ofthe meeting of the ASPNET RegionalAdvisory Committee are published inthe form of a book of 154 pages. Thispublication presents the latest news onMusa research, development and futureprospects from Malaysia, Indonesia, thePacific Islands, Sri Lanka, Bangladesh,the Philippines and a more in depth ac-count from China. It also provides up-dates on the state of banana cultivarnames and synonyms in Southeast Asia,the results of studies on nematode onthe most common banana cultivars in Vietnam, the biodiversity of wild

Musaceae in Northern Thailand and recent developments in Fusarium research in Taiwan.

Copies may be requested from the INIBAP regional office in the Philip-pines.

Managing banana and citrus diseases Proceedings of a regional workshop on disease management of banana and citrus through the use of disease-free planting materials held in Davao City, Philippines, 14-16 October 1998Edited by A.B. Molina, V.N. Roa, J. Bay-Petersen, A.T. Carpio and J.E.A. JovenISBN: 971-91751-1-7

Citrus and banana are major cashcrops for farmers in Southeast Asia.However both are experiencing dra-matic declines in yield because of dis-ease. The infections are so widespreadthat even nursery stock and parenttrees generally used to replant dis-eased plantations are infected, anddisease-free material must be soughtfrom further afield. Advances in man-aging diseases of both Citrus and ba-nana have involved developing newways to efficiently produce and distrib-ute uninfected seedlings, and of moresensitive ways to detect infections,



which may frequently be latent orsymptom-less. In the case of bananasdisease-free material is obtainedthrough tissue culture. For Citrus cer-tified disease-free seedlings from dis-ease-free nurseries are being pro-moted. In either case the lessonslearnt in developing such integrateddisease management programmes arevaluable to farmers of all types of crop.

The workshop on “Managing bananaand Citrus diseases”, jointly organisedby INIBAP and the Food and FertilizerTechnology Center, based in Taiwan,brought together researchers at theforefront of the battle against bananaand Citrus diseases in Southeast Asia.Their work on the epidemiology of viraldiseases, their ecology, detection andmethods of management for both ba-nanas and Citrus is presented in this164-page book. Results of studies onthe epidemiology, characterization andmanagement of bunchy top and viralstreak viruses, in particular, are in-cluded. As are recommendations forresearch, development and policy re-sulting from this unique workshop.

The publication is available from theINIBAP regional office in the Philip-pines.

Organic banana 2000: towards anorganic banana initiative in theCaribbeanReport of the International workshop onthe production and marketing of organicbananas by smallholder farmers, 31October-4 November 1999, SantoDomingo, Dominican RepublicEdited by M. Holderness, S. Sharrock, E.Frison and M. KairoISBN: 2-910810-40-2

Diversification has never been so im-portant, as it is now for small-scalefarmers competing in a free marketeconomy. Countries of the Caribbeanhave recognised the niche in the mar-ket for organic bananas, the DominicanRepublic currently being the largest ex-porter of organic bananas. This meet-

ing, jointly run by INIBAP, CAB Interna-tional and the Technical Centre forAgricultural and Rural Cooperation(CTA), provided a forum for discussionand information exchange for a widerange of interest groups, from farmersto retailers, with the aim of developingan initiative to support organic bananaproduction and export in theCaribbean.

This 174-page report provides paperson the current status of banana produc-tion, particular the development of or-ganic production, in the Caribbean, aswell as in Central and South Americaand Cameroon, also the prospects ofthe North American and European mar-ket, aspects of quality assurance andcertification, and production con-straints. The results of working groupsand the conclusions of the meeting arealso included. In brief, this publicationpresents an important discussion of thelatest issues surrounding organic pro-duction of bananas and lays down acomprehensive plan of action for theway forward.

Contact the Information/Communica-tions Unit at INIBAP headquarters for acopy of the book.

IPM news : Biocontrol News andInformationISSN: 0143-1404The September 2000 issue of Biocon-trol News and Information (Vol. 21,No. 3) published by CABI Biosciencehas a strong banana flavour. Almostthe whole issue of this newsletter isdevoted to banana integrated pestmanagement. Articles provide informa-tion about banana IPM research inUganda, Brazil, Ghana, Peru,Cameroon, Guadeloupe, Australia andCosta Rica. While there is a focus inmany countries on IPM for bananaweevil and nematode control, other as-pects of IPM are also covered. Theseinclude integrated management of ba-nana diseases, management of bananastreak disease, forecasting systems forreduced pesticide usage and non-chemical control methods for post har-vest diseases.

There are two contributions from INI-BAP staff. ‘IPM and INIBAP’ describesthe importance of IPM in INIBAP’s ac-tivities and the contribution made byINIBAP to promoting IPM throughworkshops, publications, supporting re-search, and conserving and distributinggermplasm. More specific involvementin different IPM strategies is sum-marised; work in Asia to develop viruscontrol programmes, success in com-bating Blood disease in Indonesia, mo-bilizing IPM for sustainable productionin Africa and on-farm testing of IPM in

East Africa. ‘Integrated approach forweevil control in Cameroon’ outlinesthe diverse tests for IPM under way inCameroon. Amongst the mechanismsunder trial are neem and wood ash, en-tomopathogenic fungi, chemical insec-ticides, ramp and pheromone traps.CRBP is also incorporating weevil resis-tance in its breeding programme.

Internet Round-Up In the latest edition of Biocontrol Newsand Information, to which INIBAP hascontributed (see above), the ‘InternetRound-up’ section is devoted to websites about bananas and pest control.With kind permission from the publish-ing editor their recommended sites arereproduced here:

The Consortium for InternationalCrop Protection (CICP) site has com-piled a list of Internet IPM resources onbanana, covering a wide range of ba-nana IPM issues, including biologicalcontrol at: http://www.ippc.orst.edu/cicp/fruit/banana.html

INIBAP’s own homepage is recom-mended for information on pest man-agement and good links at http://-www.inibap.org

The Department of Primary Indus-tries, Queensland, produces DPI notesgiving pest management advice, andpractical information on managing vari-ous pest and disease problems in arange of crops, including bananas,which you can find from:http://www.-dpi.qld.gov.au/dpinotes

Political issues concerning bananas,a section on organic bananas and a listof documents will be (it’s currentlyunder construction) available online atBanana link at:h t t p : / / w w w. g e o c i t e s . c o m / N a p aValley/1702/

The Australian Banana GrowersCouncil (ABCG) gives details of currentactivities, research programmes and ba-nana links at: http://www.abgc.org.au

Project reports and summaries areavailable online as part of the CGIAR’sSystemwide Programme for IPM:http://www.cgiar.org/spipm

The International Institute of Tropi-cal Agriculture (IITA) is managing aproject on ‘Improving plantain- and ba-nana-based systems’, a summary ofwhich is posted at:http://www.cgiar.org/spipm/dbase/projects/iitaipd.html

DfID’s Crop Protection Programmealso has a summary of a project on de-velopment of nematode resistance inbananas and plantain at:http://vwww.netcom.net.uk/~n/nri/pcpp/r6391.htm

Details of CABI Bioscience’s work onadapting novel techniques for detection


and characterization of fungi causingFusarium wilt and Sigatoka leaf spots ofbanana and plantain at: http://www.cabi.org/bioscience/annualreport_projects_egham.htmpdn

Florida Entomologist has a paper on‘Timing and distribution of attack bythe banana weevil (Coleoptera: Cur-culionnidae) in East African highlandbanana (Musa spp.)’ at: http://www.fcla.edu/FlaEnt/fe82p631.htm

There is a paper on the banana mothfrom Hort Digest at:http://www.hortdigest.com/archives/2-2000/bananamoth.htm

and another from Agropolis at http://www.agropolis.fr/actualiteevenements/le t t re / spe1099gb/ integraprotec .html

Internet Round-up is reproducedfrom Biocontrol News and Informationwith permission of CAB International.Biocontrol News and Information isavailable from CABI Bioscience,www.cabi.org.

MusaDoc CD-RomThe second edition of the MusaDoc CD-Rom, MusaDoc 2000 is out! The up-to-date versions of the INIBAP databases,MUSALIT – containing abstracts and

bibliographic records of publications onMusa, and BRIS – the database of ba-nana researchers are available. As areall of the recent publications, including

the popular Banana brochure, new fact-sheets and publications from 2000, suchas the 1999 Annual Report, ‘Banana cul-tivar names and synonyms’, ‘Evaluatingbananas: a global partnership’ and ‘Ba-nanas and food security’. The CD-Romalso gives an illustrated summary of theINIBAP’s activities. Now everyone canbe connected even if they aren’t on theweb.

Requests should be directed to theInformation/Communications Unit atINIBAP headquarters.

IMTP 2000The next in the CD-Rom productionline, is the first cutting of the IMTPdatabase! Soon to be made available onthe web, IMTP 2000 is the first effort by

INIBAP to make the entire results ofIMTP phases I and II widely availablein database form. The CD-Rom also con-tains copies of the technical guidelinesand the publication ‘Evaluating ba-nanas: a global partnership’ which givescomprehensive analysis of Phase II re-sults. In addition it provides the cata-logue of candidate and referenceclones, including those now availablefor Phase III trials, and the materialtransfer agreement. In fact all of thetools needed to take part in IMTPPhase III are here.

Requests to for copies of the IMTP2000 should be directed to the IMTPCoordinator at INIBAP headquarters.

Postharvest and plantainagroindustry in the coffee regionof ColombiaEdited by D.G. Cayón Salinas, G.A. GiraldoGiraldo and M.I. Arcila PulgarínISBN: 958-96885-0-0This 265-pages book provides the resultsof the research on postharvest issue andthe use of plantain by-products throughthe agreements signed between Cor-poica, Universidad del Quindío, Comitéde Cafeteros del Quindío and Colcien-cias. The first part of the document pre-sents a technical revue of the basic as-pects of biochemical and physiologicalprocesses which regulate and control thepostharvest of vegetable produce with

emphasis on the climacteric fruits asplantain, and discusses the main tech-nologies for the adaptation and transfor-mation of the product. It also includes20 scientific and technical articles gen-erated through the research work onplantain postharvest made by differentinstitutions from the central coffee zoneof Colombia. This publication was possi-ble due to the technical and financialsupport of the Asociación para la Inves-tigación en Plátano – ASIPLAT, and ofthe institutions that participated in re-search.

To obtain copies of this book, pleasecontact Gerardo Caón Salinas, Corpoica– Armenia. Avenida Bolívar Sector Re-givit 28 Norte, Armenia, Quindío,Colombia. E-mail: [email protected]. Price: US$10 plus han-dling and postage.


• Headquarters:Parc Scientifique Agropolis II34397 Montpellier Cedex 5 – FRANCEe-mail: [email protected]://www.inibap.orgDirectorDr Emile FRISONe-mail: [email protected] Genetic Resources ScientistDr Jean-Vincent ESCALANTe-mail: [email protected] Conservation ScientistMs Suzanne SHARROCKe-mail: [email protected] Information/CommunicationsMs Claudine PICQe-mail: [email protected] in charge MGISMs Elizabeth ARNAUDe-mail: [email protected] ManagerMr Thomas THORNTONe-mail: [email protected]

• Regional Office for Latin America andthe CaribbeanRegional CoordinatorDr Franklin E. ROSALESAssociate Scientist : Musatechnology transferLuis POCASANGRE

C/o CATIEApdo 60-7170 Turrialba, COSTA RICATel/Fax: (506) 556 2431e-mail: [email protected]

• Regional Office for Asia and the PacificRegional CoordinatorDr Agustín MOLINAC/o Collaborator Center IRRICollege, Laguna 4031PHILIPPINESFax: (63 2) 845 05 63e-mail: [email protected]

• Regional Office for West and CentralAfricaRegional CoordinatorDr Ekow AKYEAMPONGC/o CRBP – BP 12438Douala, CAMEROONFax: (237) 42 91 56e-mail: [email protected]

• Regional Office for Eastern andSouthern AfricaRegional CoordinatorDr Eldad KARAMURAAssociate Scientist: Technology transferGuy BLOMMEPO Box 24384Kampala, UGANDA

Fax: (256-41) 28 69 49e-mail: [email protected]

• INIBAP Transit Center (ITC)Officer in chargeMs Ines VAN DEN HOUWEKatholieke Universiteit LeuvenLaboratory of Tropical Crop ImprovementKasteelpark Arenberg 13,B-3001 LeuvenBELGIUMFax: (32 16) 32 19 93e-mail: [email protected]

• Associate Experts, NematologyMs Inge VAN DEN BERGHC/o VASIVan Diem, Than TriHanoi, VIETNAMFax: (84) 4 861 39 37e-mail: [email protected] Thomas MOENSC/o CORBANALa Rita Research StationApdo 390-7210Guápiles, COSTA RICAFax: (506) 763 30 55e-mail: [email protected]

Typescripts should be prepared in Eng-lish, French or Spanish and submittedin duplicate to the Managing Editor.They should be double-spaced through-out. All pages (including tables figures,legends and references) should benumbered consecutively. Include thefull name of all the authors of thepaper, together with the addresses ofthe authors at the time of the work re-ported in the paper. Indicate also theauthor nominated to receive corre-spondence regarding the paper.

If the typescript was prepared on acomputer, please send a copy ondiskette (or by e-mail) along with theprinted ones, indicating the name andversion of the wordprocessor used. • Abstracts: An abstract not exceed-

ing 200-250 words should be sent inthe same language as the typescript,as well as translations (including thetitle) into the two other languages, ifthis is possible.

• Acronyms: These should be writtenin full the first time they appear inthe text, followed by the acronym inparenthesis.

• References: All literature referencesmade in the text should be referredto by author(s) and year of publica-tion (e.g.: Sarah et al. 1992, Rowe1995). A list of references, in alpha-betical order, should be provided atthe end of the text.

Please follow the style shown below:Periodicals: Sarah J.L., C. Blavignac &

M. Boisseau. 1992. Une méthode delaboratoire pour le criblage variétaldes bananiers vis-à-vis de la résis-tance aux nématodes. Fruits 47(5):559-564.

Books: Stover R.H. & N.W. Simmonds.1987. Bananas (3rd edition). Long-man, London, United Kingdom.

Articles (or chapters) in books: BakryF. & J.P. Horry. 1994. Musa breedingat CIRAD-FLHOR. Pp. 169-175 inThe Improvement and Testing ofMusa: a Global Partnership (D.R.Jones, ed.). INIBAP, Montpellier,France.

Tables: These should be numberedconsecutively and referred to by thesenumber in the text. Each table shouldinclude a title.

Illustrations: These should be num-bered consecutively and referred to bythese numbers in the text. Each illus-tration should include a clear and sim-ple caption.Graphs: provide the corresponding rawdata with the graphs.Drawings: provide originals if this ispossible.Black and white photographs: providethem on bright paper and with goodcontrast.Colour photographs: provide goodquality proofs and films or originalslides.Note: When plant material used for theexperiments reported originates or isregistered in the INIBAP genebank, itsaccession number (ITC code) shouldbe indicated within the text or in atabular form.

Thank you in advance for followingthese instructions

This will facilitate and acceleratethe editing work.

Instructions to authors

INIBAP addresses

The following publications are available from headquarters:INIBAP 2000. M. Holderness, S. Sharrock, E. Frison & M. Kairo (eds). Organic

banana 2000: Towards an organic banana initiative in the Caribbean. Reportof the international workshop on the production and marketing of organicbananas by smallholder farmers. 31 October-4 November 1999, SantoDomingo, Dominican Republic.

INIBAP 2000. Annual Report 1999.CIRAD/INIBAP 2000. Bananas.INIBAP. 2000. G. Orjeda (compil.). Evaluating bananas: a global partnership.

Results of IMTP Phase II.INIBAP/EARTH/IDRC. 1999. F.E. Rosales, S.C. Tripon & J. Cerna (eds).

Organic/environmentally friendly banana production. Proceedings of aworkshop held at EARTH, Guácimo, Costa Rica, 27-29 July 1998 (in press).

INIBAP/CRBP/CTA/CF. 1999. C. Picq, E. Fouré & E.A. Frison (eds). Bananas andfood security/Les productions bananières: un enjeu économique majeur pourla sécurité alimentaire. Proceedings of an International Symposium held inDouala, Cameroon, 10-14 November 1998.

INIBAP/FHIA. 1999. F.E. Rosales, E. Arnaud & J. Coto (eds). A tribute to thework of Paul H. Allen: a catalogue of wild and cultivated bananas.

INIBAP/RF/SDC. 1999. E.A. Frison, C.S. Gold, E.B. Karamura & R.A. Sikora(eds). Mobilizing IPM for sustainable banana production in Africa.Proceedings of a workshop on banana IPM held in Nelspruit, South Africa, 23-28 November 1998.

INIBAP 1999. E. Akyeampong (ed.). Musa Network for West and Central Africa.Report of the second Steering Committee meeting held at Douala, Cameroon,15-16 November 1998.

INIBAP 1999. Annual Report 1998.INIBAP 1999. K. Shepherd. Cytogenetics of the genus Musa.INIBAP 1998. E. Akyeampong (ed.). Musa Network for West and Central Africa.

Report of the first Steering Committee meeting held at Douala, Cameroon, 8-10 December 1997.

INIBAP 1998. E.A. Frison & S.L. Sharrock (eds). Banana streak virus: a uniquevirus-Musa interaction? Proceedings of a workshop of the PROMUSA virologyworking group held in Montpellier, France, 19-21 January 1998.

INIBAP 1998. C. Picq (ed.). Segundo seminario/taller de la Red regional deinformación sobre banano y plátano de America Latina y el Caribe. San José,Costa Rica, 10-11 July 1997.

INIBAP 1998. B.K. Dadzie. Post-harvest characteristics of black Sigatokaresistant banana, cooking banana and plants hybrids. INIBAP TechnicalGuidelines 4.

INIBAP 1998. G. Orjeda in collaboration with the PROMUSA working groups onSigatoka and Fusarium. Evaluation of Musa germplasm for resistance toSigatoka diseases and Fusarium wilt. INIBAP Technical Guidelines 3.

INIBAP/ACIAR 1997. E. Arnaud & J.P. Horry (eds). Musalogue, a catalogue ofMusa germplasm: Papua New Guinea collecting missions 1988-1989.

INIBAP/CTA/FHIA/NRI/ODA 1997. B.K. Dadzie & J.E. Orchard. Post-harvestRoutine Screening of Banana and Plantain Hybrids: Criteria and Methods.INIBAP Technical Guidelines 2.

INIBAP/CTA 1997. P.R. Speijer & D. De Waele. Screening of Musa Germplasmfor Resistance and Tolerance to Nematodes. INIBAP Technical Guidelines 1.

INIBAP/The World Bank 1997. E.A. Frison, G. Orjeda & S. Sharrock (eds).PROMUSA: A Global Programme for Musa Improvement. Proceedings of ameeting held in Gosier, Guadeloupe, March 5 and 9, 1997.

INIBAP-IPGRI/CIRAD. 1996. Descriptors for Banana (Musa spp.).

The following publications are available from Asia and the Pacificoffice:INIBAP. 2000. R.V. Valmayor, S.H. Jamaluddin, B. Silayoi, S. Kusumo, L.D. Danh,

O.C. Pascua & R.R.C. Espino. Banana cultivar names and synonyms inSoutheast Asia.

INIBAP-ASPNET 2000. A.B. Molina & V.N. Roa (eds). Advancing banana andplantain R & D in Asia and the Pacific. Proceedings of the 9th INIBAP-ASPNET Regional Advisory Committee meeting held at South ChinaAgricultural University, Guangzhou, China, 2-5 November 1999.

INIBAP-ASPNET/FFTC 2000. A.B. Molina, V.N. Roa, J. Bay-Petersen, A.T. Carpioand J.E.A. Joven (eds). Managing banana and citrus diseases. Proceedings ofa regional workshop on disease management of banana and citrus throughthe use of disease-free planting materials held in Davao City, Philippines, 14-16 October 1998.

INIBAP/ASPNET 1999. V.N. Roa & A.B. Molina (eds). Minutes: Eighth meeting ofINIBAP/ASPNET Regional Advisory Committee (RAC) hosted by theQueensland Horticulture Institute (DPI) in Brisbane, Australia, 21-23October 1998.

INIBAP/ASPNET 1998. Minutes: Seventh meeting of INIBAP/ASPNET RegionalAdvisory Committee (RAC) hosted by the Vietnam Agricultural ScienceInstitute (VASI) in Hanoi, Vietnam, 21-23 October 1997.

INIBAP/ASPNET 1997. V. N. Roa & R. V. Valmayor (eds). Minutes: Sixth meetingof INIBAP/ASPNET Regional Advisory Committee (RAC) hosted by NationalResearch Center on Banana (ICAR) in Tiruchirapalli, India, 26-28 September1996.

INIBAP/ASPNET 1996. R. V. Valmayor, V. N. Roa & V. F. Cabangbang (eds).Regional Information System for Banana and Plantain - Asia and the Pacific(RISBAP): Proceedings of a consultation/workshop held at Los Baños,Philippines, 1-3 April 1996. (ASPNET Book Series No. 6).

Publications from INIBAP

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PROMUSA IINFOMUSA — Vol 9, N° 2

PROMUSA N° 6

Contents

Minutes of the second PROMUSA Steer-ing Committee meeting Bangkok, Thai-land, 7 and 8 November 2000 . . . . .p. I

Report of the PROMUSA Genetic improve-ment working group . . . . . . . . . . . .p. IV

Report of the PROMUSA Sigatoka workinggroup . . . . . . . . . . . . . . . . . . . . . . . .p. VII

Report of the PROMUSA Fusarium wiltworking group . . . . . . . . . . . . . . . . . .p. X

Report of the PROMUSA Nematologyworking group . . . . . . . . . . . . . . . . .p. XII

Report of the PROMUSA Virology workinggroup . . . . . . . . . . . . . . . . . . . . . . .p. XIV

What is PROMUSA ?

The Global Programme for MusaImprovement (PROMUSA) is a broad basedprogramme which aims at involving all themajor players in Musa improvement. It wasdeveloped as a means to link the workcarried out towards addressing the problemsof export banana producers, with thoseinitiatives directed towards improving bananaand plantain production at the subsistenceand smallholder level. The global programmebuilds upon existing achievements and isbased upon ongoing research initiatives.PROMUSA is therefore a mechanism tofurther maximize the outputs and acceleratethe impact of the overall Musa improvementeffort. The programme is an innovativemechanism to bring together research carriedout both within and outside the CGIAR,creating new partnerships between NationalAgricultural Research Systems (NARS) andresearch institutes in both developing anddeveloped countries. The formation of suchpartnerships will also contribute tostrengthening the capacity of NARS toconduct Musa-related research.The major thrust of PROMUSA is to developa wide range of improved banana varietiesfrom which growers worldwide can selectthose most suited to their needs. Theprogramme brings together conventionalbreeding based on hybridization techniqueswith genetic engineering andbiotechnological breeding approaches. Thisbroad-based genetic improvement effort issupported by research being carried out onspecific pests and diseases within thevarious PROMUSA working groups. Anefficient mechanism for evaluating newvarieties produced within the framework ofPROMUSA is also an essential component ofthe programme.

PROMUSAA global Programme for Musa Improvement

Present: Emile Frison (INIBAP)—Chairperson, Abdou Tenkouano (IITA),Mary Wabule (NARS of East andSouthern Africa), Luis Sequeira (ARIsof North America), Adiko Amoncho(NARS of West and Central Africa),Elizabeth Aitken (ARIs Australia—Pa-cific region), Philippe Lepoivre (ARIsof Europe), David Berroa (NARS ofLatin America and Caribbean), LucSas (Chair, PROMUSA Suppor tGroup), Jean-Vincent Escalant(PROMUSA Secretary), SuzanneSharrock (rapporteur). Observers: CliffGold (IITA), Eldad Karamura (INIBAP).Absent with apologies: P. Faylon(NARS of Asia and the Pacific).

Programme support group ofPROMUSAThe role of the PROMUSA SupportGroup was explained to the SteeringCommittee. This is an informal groupof donors and other stakeholders andmeetings with them provide an oppor-tunity to discuss banana issues andkeep bananas on the agenda. How-ever the meetings are mainly for infor-mation exchange and usually thereare no financial commitments made.

Role of the SteeringCommitteeIt was noted that this meeting shouldbe considered the first official PRO-MUSA Steering Committee meeting,which consists of members who havebeen properly appointed by the vari-ous constituencies they are represent-ing. The roles and responsibilities ofthe Steering Committee have beenconfirmed as published in the originalPROMUSA publication. In the sameway, the role of the Secretariat ofPROMUSA has been confirmed as re-porting to the Steering Committee.

Terms of office andattendance at meetingsIt was felt important to have somecontinuity in the composition of theSteering Committee (SC) and it wastherefore decided that the terms of of-fice of SC members should be twoyears, renewable three times. It wassuggested that the representationfrom IITA and IPGRI should be institu-tional rather than personal, so that thesame person could serve longer thanthe normal maximum of 6 years. Itwas agreed that if a member is unableto attend any meeting, he/she shouldappoint an alternate to attend in theirplace.

Minutes of the second PROMUSASteering Committee meeting Bangkok, Thailand, 7 and 8 November 2000

II PROMUSA INFOMUSA — Vol 9, N° 2

PROMUSA project fundingIt was noted that there seemed to besome confusion amongst PROMUSAparticipants regarding the role of thePROMUSA Secretariat and SteeringCommittee in the identification ofproject funding. It was agreed thatthere was a need to clarify that themain role of PROMUSA is to facili-tate collaboration and partnerships,and not to provide funds. It was alsoagreed that the Secretariat couldhelp participants develop project pro-posals upon request. With regard toprojects being developed in theframework of PROMUSA, it was feltthat these should not be routinelyevaluated by the Steering Committee,as this would add another layer ofbureaucracy into the project develop-ment process.

Reporting on PROMUSAactivities

Reporting to the Steering CommitteeIt was noted that during the openingsession of the PROMUSA meeting,some of the reports provided by theworking group convenors were verygeneral and not sufficiently focused onprogress in the last two years. ThePROMUSA Secretary reported thatthe working group convenors had ex-perienced difficulties in obtaining feedback from the working group membersand that generally over the last twoyears, the convenors of the workinggroups had not been playing a suffi-ciently active role. In this respect itwas felt that the role of the convenorhad not been made sufficiently clearand it was noted that the workinggroups at this meeting were dis-cussing this issue. With regard to re-porting, it was agreed that the Secre-tariat should report to the SteeringCommittee every six months. Re-questing the working group convenorsto report to the Secretariat at a similarfrequency would facilitate this.

PROMUSA NewsThe Steering Committee commendedINIBAP for the PROMUSA News,which is published twice yearly in IN-FOMUSA . I t was noted that thePROMUSA Web site is being updatedand will also become an importantmeans of sharing information and pro-viding results from the programme.

Sharing Information within PROMUSAThe importance of the email list-servers as means of sharing informa-tion was highlighted, especially forthose researchers who do not haveeasy access to the Internet. Howeverit was also noted that the listserversare presently not being well used.Several reasons for this were identi-fied, including the fact that peoplewere not used to working in this wayand that many communications areon a one-to-one basis. It was agreedthat the working group convenors andmembers should be encouraged tomake more use of the listservers.

Inter-group contactsIt was agreed that greater efforts arerequired to ensure better interactionsbetween working groups. In this re-spect, it was agreed that a ‘convenorscommittee’ be established to bring to-gether the convenors of each workinggroup. This committee should meetformally prior to each global PRO-MUSA meeting. Further informal con-tacts between the convenors shouldalso be encouraged.

Feedback from regional networksThe Steering Committee agreed thatthe PROMUSA Secretariat should beproactive in ensuring information ex-change between PROMUSA and theregional networks. This is to ensurethat PROMUSA really is addressingthe needs at a regional level.

Financing for PROMUSAIt was emphasized that PROMUSAwas not set up with the intention that itshould become a funding mechanism,however, it was also noted that the

operation of the programme does re-quire financial support and such fundsneed to be identified. In this respect, itseems unlikely that sufficient fundingfrom donors will become available inthe near future.

The Steering Committee agreedthat participants in PROMUSA shouldhave a stake in the funding of theprogramme, through, for example,covering their costs of participating inmeetings. It was felt that the willing-ness of participants to cover suchcosts would also help to demonstrateto potential donors the value of theprogramme. It was noted that someparticipants did indeed cover theirown costs for this and previous meet-ings. It was agreed that large projectsdeveloped in the framework of PRO-MUSA could include meeting costs inthe project budget.

In the area of funding, i t wasagreed that all Steering Committeemembers should make efforts to fol-low up on contacts with donors and inthis way assist in the search for finan-cial support for PROMUSA. In this

INFOMUSA — Vol 9, N° 2 PROMUSA III

respect, it was noted that the Secre-tariat must keep the Steering Com-mittee informed of proposals beingdeveloped and the progress of pro-posals.

Meetings of PROMUSAIt was noted that the Internationalsymposium on molecular and cellularbiology on banana which will takeplace every two years, would be anappropriate event with which to linkPROMUSA global meetings. Thecosts of holding global meetings werediscussed, and it was suggested thatefforts be made to approach founda-tions and private companies for sup-port for future meetings.

It was suggested that linking futurePROMUSA meetings with relevantsymposia would facilitate the identifi-cation of funding by par ticipantsthrough travel grants to participate inscientific meetings etc. A further ad-vantage of such linkages would alsobe in helping to ensure that PRO-

MUSA participants are aware of thelatest research results being pre-sented at the symposium.

New initiatives under the umbrella of PROMUSA

Banana Genomics ConsortiumThe PROMUSA Secretariat provideda report to the Steering Committee onthe Banana Genomics Consortium.This consortium was set up in Mont-pellier earlier this year to allow the de-velopment of Musa genomics ‘masterplan’ with the free exchange of infor-mation between consortium members,but a limit on the exchange of informa-tion outside the consortium. The aimof the consortium is to focus on pre-competitive research and all resultsfrom research carried out by consor-tium members will be made freelyavailable. The consortium has re-quested the Steering Committee ofPROMUSA to endorse its operation inthe framework of PROMUSA. It was

explained that this consortium has itsown ‘Scientific Committee’ and thereis some degree of confidentiality re-garding the development of its activi-ties. The members of the consortiumare all members of the PROMUSAGenetic improvement working group.The Steering Committee membersagreed that the consortium is focusingon the genetic improvement of Musaand that its aims and objectives coin-cide with those of PROMUSA. It wasagreed that this consortium provides amechanism for researchers to havesome level of confidentiality aroundtheir work, while still following in thespirit of collaboration which is PRO-MUSA. It was therefore agreed thatthe Musa Genomics Consor t iumshould operate under the umbrella ofPROMUSA.

Banana weevils as a new PROMUSA priorityWhen PROMUSA was first estab-lished banana weevils were not con-sidered to be a global production con-straint and genetic improvement was

IV PROMUSA INFOMUSA — Vol 9, N° 2

not considered the most appropriatetechnology for control of this pest.However in recent years this situationhas changed. Breeding tools have de-veloped considerably and sources ofresistance to weevils have been iden-tified. Thus breeding for weevil resis-tance, using both conventional andbiotechnological approaches is nowseen as a viable option. Therefore thePROMUSA Secretariat has receivedseveral requests that weevil resis-tance be put on the agenda of the Ge-netic Improvement working group andthat a working group on weevils beformed.

Following some discussion, theSteering Committee agreed that an in-formal group on weevils should be es-tablished. This group should gatherfurther information on what research isbeing done where and report back atthe next Steering Committee meeting

Latin American biotechnology networkInformation was provided on abiotechnology network that has beenestablished in Latin America in theframework of MUSALAC. This net-work has a focus on genetic transfor-mation and molecular genetics. TheSteering Committee agreed that thenetwork should be encouraged to op-erate under the umbrella of PRO-MUSA in the framework of the Geneticimprovement working group.

Public awarenessIt was noted that PROMUSA partici-pants attend a large number of meetingsaround the world. It was suggestedthat working groups develop the con-tent of posters that can be used bymembers to present at meetings. Thesecretariat should provide support tothe development of these posters.

Election of ChairpersonEmile Frison was unanimously re-elected as Chairperson for 2000/2001.

SecretariatThe Steering Committee confirmedthat INIBAP should continue to providethe Secretariat for PROMUSA.

Frequency of SteeringCommittee meetingsIt was confirmed that the SteeringCommittee should attempt to meetonce per year. Additional ad hocmeetings could be called if necessary.The next Steering Committee meetinghas to be defined.

Report of thePROMUSA Geneticimprovement working groupPar ticipants: Maria Elena Aguilar(CATIE, Costa Rica), Françoise Car-reel (CIRAD, Guadeloupe), FrançoisCote (CIRAD, France), James Dale(QUT, Australia), Jaroslav Dolezel (IEB,Zchecie), Antonio Figueira (CENAUSP, Brasil), Rafael Gomez Kosky(IBP, Cuba), Peter Gresshoff (CRCTPP,Australia), Pat Heslop-Harrison (JIC,UK), Chr istophe Jenny (CIRAD,Guadeloupe), Dieter Kaemmer (Frank-furt Univ. Biocenter, Germany), DaleKrigsvold (FHIA, Honduras), GomezLim (CINVESTAV, Mexico), Do NangVinh (AGI, Viet-Nam), Sebastião deOliveira e Silva (EMBRAPA, Brasil),Luis Pérez Vicente (INIVIT, Cuba),Michael Pillay (IITA, Nigeria), NicolasRoux (IAEA, Austria), Lazlo Sagi (KUL,Belgium), S. Sathiamoorthy (NRCB,India), Jorge Sandoval (CORBANA,Costa Rica), Rony Swennen (KUL,Belgium), Abdou Tenkouano (IITA,Niger ia), Kodjo Tomekpe (CRBP,Cameroon), S. Uma (NRCB, India),P.K. Valsalakumari (KAU, India).Rapporteurs: Jaroslav Dolezel and S.Sathiamoorthy.

Administrative and generalmattersS. Sathiamoor thy (NRCB) and J.Dolezel (IEB) were appointed con-

venors for the group. S. Sathiamoorthywill be responsible for the Breedingand genetics sub-group while J.Dolezel will be responsible for the Ge-netic engineering sub-group.

The working group discussed theproblem of insufficient funding forMusa research given the global impor-tance of banana and plantain. Devel-opment genomics research, whichhas the potential to impact on allareas of Musa improvement, will notbe feasible without considerable in-vestment. The group also agreed thatas part of its role PROMUSA should: • Assist in setting global priorities

for research and improvement• Be a platform for

communication/interaction• Be a depository of information

and assist in its distribution (new publications, tools, materials)

• Organize meetings—the globalPROMUSA meetings and specialized satellite meetings

• Identify and contact potential donors• Screen calls for project proposals

and distribute the information• Assist in project preparation.The working group agreed that as partof their role, convenors should:• Prepare agenda for group meetings• Lead discussions during

the meetings• Stimulate the interaction between

group members in between the meetings

• Accompany PROMUSA secretary to meet potential donors.The large size of the group and the

extensive discussions did not allow forthe presentation of scientific reportsnor for discussions with other workinggroups. Splitting the Genetic improve-ment working group into two smallergroups on breeding/genetics (whichshould maintain the status of a corePROMUSA group) and a biotechno-logy/genomics group should be con-sidered.

Breeding and genetics sub-groupResearch priorities of the Breedingand genetics subgroup were identifiedas follows:

INFOMUSA — Vol 9, N° 2 PROMUSA V

• Establishment of a regionalcollaborative programme for MusaImprovement in Asia, the majorcentre of origin and diversity of the crop

• Prospecting for new wild /landracestypes through explorations in areasof natural diversity especially in South and Southeast Asia

• Characterization and evaluation of varieties for new sources of resistance to major pests and diseases; Sigatoka, nematodes, Fusarium wilt and weevils (corm and stem weevils)

• Compilation of information on existing global Musagenetic diversity

• Emphasis on strengthening of diploid breeding for developing new breeding stock using classical andbiotechnological tools

• Widening of genetic base using conventional and biotechnological approaches.

Genetic engineering sub-groupWithin the Genetic engineering sub-goup, it was agreed that there was noneed to change overall priorities andstrategies as established during theprevious two PROMUSA meetings.However, it was noted that there is anincreasingly urgent need to stimulatethe development of Musa genomicsand that this target should be giventhe highest priority. The Banana Ge-nomic Consortium, which was estab-lished within the PROMUSA initiativein April 2000 may play a leading role.Members of the working group werealso briefed about the establishmentof a Musa Biotechnology network inLatin America. The possibility to es-tablish closer links between themshould be considered.

Tissue and cell cultures in vitroA methodology for the establishmentand maintenance of embryogenic cell

suspension cultures has been devel-oped and is being transferred to vari-ous laboratories. Embryogenic cul-tures are considered suitableexperimental material for genetictransformation, mutagenesis, andprotoplast isolation in Musa. Themajor constraint is the genetic insta-bility of the suspension cultured cellsand f ield-testing of regeneratedplants has been strongly recom-mended. While studying the natureand mechanisms of genetic variationin vitro is considered unrealistic,there is an urgent need to isolatemarkers for at least some of the mostfrequent off types regenerated fromsuspension cultures. The markerswould be invaluable for early screen-ing and might be also useful in opti-mising culture conditions to reducegenetic instability. Tissue cultureshould also be considered as a toolfor the delivery of improved hybrids,virus eradication and for long-termconservation via cryopreservation.

Genetic transformationSignificant progress has been made inthe development of efficient transfor-mation systems for Musa. The tech-nology is being transferred to variouslaboratories and transgenic bananaplants have been obtained in at leastfive public laboratories. Generally,Agrobacterium-based protocols arepreferred over biolistic approaches asthey are more effective, result in lowernumber of integrated copies and lowerfrequency of transgene silencing.While most of the current projects arefocused on transformation of existingcultivars, it has been proposed to ex-tend the technology to diploid parentsand landraces, and incorporate trans-genic plants in existing breeding pro-grammes. Major constraints involvethe selection systems based on resis-tance to herbicides and antibiotics,which may have a negative impact onthe public acceptance of transgenicbananas and plantains. There is ageneral interest to collaborate inbiosafety issues as well as in the useof embryogenic cell suspension cul-

tures for transformation. On the otherhand, limited collaboration has beenforeseen in the area of promoters andvectors, namely due to potential prob-lems with intellectual property rights.

Mutagenesis Physical mutagenesis, namely gammairradiation, has been successfullyused in some research projects andseveral clones with agriculturally inter-est ing traits (ear l iness, reducedheight, disease resistance, increasedyield) were reported. Major constraintsinclude the problems with chimerismand the need to screen large popula-tions of plants. In vitro systems forrapid dissociation of chimeras as wellas systems for early screening of de-sired characters are urgently needed.While most of the current projects arefocused on mutation induction in exist-ing triploid cultivars, it has been pro-posed to generate more mutants indiploid parents and landraces. In addi-tion to gamma irradiation, fast neutronirradiation should be employed. More-over, the use of chemical and inser-tional mutagenesis should be consid-ered as alternatives to irradiation.Mutagenesis is considered an attrac-tive tool to obtain plants with traitswhich are not available in nature. It isexpected that mutagenesis will playan increasingly important role in Musagenome mapping projects, where itwill be used to generate deletionstocks and knockout mutants.

Cytogenetics Significant progress has been madein the area of Musa cytogenetics.DNA flow cytometry became a widelyaccepted method for rapid ploidyscreening and the methodology hasbeen transferred to two breeding sta-tions. The method has also beenused to verify ploidy levels of acces-sions held at the INIBAP Transit Cen-tre at Leuven. Given the relativelyhigh proportion of accessions wherethe ploidy level was not confirmed(~9%), the analysis of other collec-tions is strongly recommended. Morerecent results indicate the suitability

VI PROMUSA INFOMUSA — Vol 9, N° 2

of flow cytometry for rapid estimationof genomic constitution in unknownaccessions and hybrids as well as fordetection of aneuploidy. Two labora-tories (IAEA, IEB) provide the servicefor institutions, which lack the neces-sary equipment. Methods in molecu-lar cytogenetics (fluorescence in situhybridization—FISH, genomic in situhybridization—GISH) have been de-veloped. FISH has been used toanalyse the structure of Musa chro-mosomes at the molecular level, in-cluding the genomic distribution ofmobile genetic elements and BSV in-tegrants. GISH has been extremelyuseful in determining genomic consti-tution in hybrids. Detailed characteri-zation of the Musa karyotype, includ-ing the identification of individualchromosomes and detection of chro-mosome structural rearrangementwill be a priority of Musa cytogeneticsin the near future.

AneuploidyAneuploidy may become an impor-tant tool in Musa genetic studies. Re-cent results indicate a possibility togenerate large numbers of aneu-ploids (mostly hypoploid via the lossof one or more chromosomes). Aneu-ploids have been obtained after re-generation from embryogenic cellsuspension cultures, after irradiationand after a treatment with mitoticspindle poisons. DNA flow cytometrywas found suitable for rapid detectionof plants with aneuploid chromosomenumber. Once obtained, aneuploidplants may be maintained by vegeta-tive propagation. Until now, aneu-ploids have been generated fromtriploid stocks. It has been proposedto generate and characterize a seriesof aneuploids from selected diploidgenotypes.

Gene silencing and genome interactionThe phenomena of gene silencingand genome interaction should be in-tensively studied as they may havesignificant impact on current Musa

improvement programmes. As mostof the breeding programmes involvehybrid development, gene silencingand genome interaction may influ-ence the characteristics of newly ob-tained materials. Alternation of geneexpression may be an impor tantmechanism for generating geneticvariability in vitro while gene silencingmay alter the expression of trans-genes. Recent results indicate in-volvement of the A genome of Musain the activation of BSV sequencesintegrated into the B genome. Theunderstanding of underlying mecha-nisms might provide tools to developmaterials resistant to BSV.

GenomicsResearch in Musa genomics has beenidentified as the main priority for thegroup. Despite the importance of ba-nanas and plantains, genomics stud-ies in Musa are lagging behind othermajor crops. It is expected that the in-formation derived from Musa genomicstudies will help to create cultivarswith optimal performance in differentbiological, ecological and cultural envi-ronments.Three main areas of Musa genomicsto be developed were discussed:

Genetic mapsThere is an urgent need to develop asaturated genetic map of Musa. Atpresent three mapping populationsare available at CIRAD/CRBP, Uni-versity of Queensland and IITA. Anew segregation population is to beestablished by INIBAP. It has beenrecommended that molecular mark-ers are exchanged between laborato-ries and that there is collaboration inincreasing density of the maps. Thework should be focused on the devel-opment of STMS (Sequence TaggedMicrosatellite Site) markers which arelocus-specif ic, co-dominant andhighly polymorphic. Although the de-velopment of STMS markers is ex-pensive, once establ ished themethodology is easily transferable.The group also discussed a need totransfer mapping populations to otherlocations.

Physical mapsPhysical maps and integrated geneticand physical maps are urgentlyneeded for sequencing. An extensivelist of resources, which will be re-quired for physical mapping, includesBAC (Bacterial Artificial Chromo-some) libraries, cDNA (complemen-tary DNA) libraries and ESTs (Ex-pressed Sequence Tags). Althoughthere has been no strategic invest-ment in Musa genetics during the lastfew years, some materials are al-ready available. Two BAC libraries(Calcutta 4) are available (at cost)from Texas A&M University BAC Cen-tre, new BAC libraries are being con-structed by CIRAD, CICY and IEB,leaf cDNA library has been devel-oped at CINVESTAV. Furthermore,Zenecca developed over 80,000ESTs. While urgently required, physi-cal mapping will demand consider-able investment in terms of equip-ment, consumables and qualifiedpersonnel. At present, two laborato-ries (CIRAD, IEB) are equipped withrobotic equipment suitable for con-struction and handling of DNA li-braries and for preparation of DNAarrays, one laboratory (UL) is pur-chasing a microarrayer. To make thefull use of currently available re-sources, it will be important to coordi-nate existing research efforts.

Gene discoveryWhile map-based gene cloning re-mains an attractive route for gene iso-lation, other approaches towards genediscovery should be considered in re-search projects. These include com-parative genomics, differential screen-ing and gene tagging.

Marker assisted breedingAlthough attractive, marker assisted(MAS) breeding is still largely an aspi-ration for the future for Musa improve-ment. The reason being the delay inthe development of Musa genomics,and the lack of suitable molecularmarkers linked to traits of interest, e.g.disease resistance and partheno-carpy. At present, only markers that

INFOMUSA — Vol 9, N° 2 PROMUSA VII

allow rapid detection of the presenceof A and B genomes are available.

Germplasm assessment(biodiversity)New mater ials obtained from ex-ploratory missions as well as materi-als held at existing collections (espe-cial ly those in Asia) should beextensively characterized at differentlevels (morphological, agronomic,molecular). The character izationshould include determination of chro-mosome number, genome size andgenomic constitution. Molecular mark-ers (RFLP, STMS, CAPS, AFLP) areavailable for classification and identifi-cation of Musa germplasm. They havebeen used by CIRAD to characterizeaccessions held at the INIBAP TransitCentre in Leuven. The classification ofa relatively high proportion of acces-sions was not confirmed (~10%), indi-cating a need to analyse other collec-t ions, too. The working groupsuggested that the evaluation of invitro collections should include dupli-cations in field conditions. It was alsosuggested that access to the MGISdatabase should be improved.

Report of thePROMUSA Sigatokaworking groupParticipants: E. Aitken (CRC TPP,Australia), C. Abadie (CRBP/CIRAD,Cameroon), J.P. Busogoro (Univ.Gembloux, Belgium), J. Car l ier(CIRAD, France), B. Ful ler ton(HortResearch, New Zealand), A.Gutierrez Rojas (CORPOICA, Colom-bia), M. Guzman (CORBANA, CostaRica), Z. Jiang (SCAU, China), N.Masdek (MARDI, Malaysia), G. Molina(INIBAP), W. Tushemereirwe (NARO,Uganda), L. Perez Vicente (INISAV,Cuba), G. Rivas (CATIE, Costa Rica),R. Selvarajan (NRCB, India), B.Williams (QDPI, Australia).Joint convenors: Jean Carlier and BobFullerton.

IntroductionAt the beginning of the working groupsession, each participant briefly madea presentation of current develop-ments in their research group. Therefollowed a discussion on the identifica-t ion and distr ibut ion of banana

pathogens in Asia. The durability ofresistance to diseases was also amajor point of discussion. Participantswere then allowed to review and up-date research priorities. These aregiven in detail below. The sources ofinformation and comments are givenin brackets in order to facilitate furtherexchanges within and between theworking groups. Finally the opportuni-ties provided by PROMUSA and sug-gested activities within the programmewere discussed.

Research priorities

1. Determine the distribution andrelative incidences of M. eumusae,M. fijiensis and M. musicolain different countries of Southeast Asia.Following the publication in Phy-topathology (Carlier et al. 2000), Sep-toria Leaf Spot disease, has beenadopted as the common name of thedisease caused by Mycosphaerellaeumusae (anamorph Septoria eu-musae). This disease may have beenpreviously observed in India (Dr Sel-varajan, NRCB). A formal Latin de-

Meeting of the Genetic improvment working group.

VIII PROMUSA INFOMUSA — Vol 9, N° 2

scription of Mycosphaerella eumusaewill be published to establish it as avalid species (QDPI, CIRAD).

Today, the presence of the pathogenhas been confirmed in southern India,Sri Lanka, Thailand, Malaysia, Mauri-t ius, Reunion Island and Niger ia(CIRAD). Septoria leaf spot diseasehas not yet been recorded in China(Dr Jiang, SCAU).

The distribution and relative impor-tance of the three different pathogenscausing Sigatoka leaf spot-like dis-eases in Asia is widely unknown. Inorder to initiate investigations to an-swer such questions, a survey is on-going in India (NRCB), Malaysia(MARDI), Sri Lanka (RARC), Philip-pines (IPB/UPLB) and China (SCAU).CIRAD is also supporting this projectby defining protocols and carrying outcomplementary analysis of leaf sam-ples. The survey should continue andexpand into other Asian countries

2. Develop appropriate diagnostictools for the identification of Mycosphaerella leaf pathogensTo enable surveys of different My-cosphaerella species to be conducted,a training course in basic fungal iden-tification using morphological charac-ters is necessary. A manual with de-scr ipt ions of symptoms andmorphological characters of the differ-ent species would be very useful. Thedevelopment of molecular methods todiscriminate between the species isalso essential for confirmation and fordiagnosis of mixed infections or infec-tions on old leaf material. Such amethod has already been developedusing restriction assay of PCR-ampli-fied ITS regions of rDNA (Dr Carlier,CIRAD). However, this method re-quires the isolation and cloning of thefungi from leaf samples. A quick testfor rapid local identification of thepathogens without isolation could beuseful for analysis of numerous sam-ples. The primers were defined in theITS sequence for the detection M. fi-jiensis and M. musicola (Johansonand Jeger 1993). However, theseprimers are not sufficiently specific todist inguish them from other My-cosphaerella species which may be

isolated on banana leaves (10 My-cosphaerella or species belonging torelated anamorph genera were de-tected—Dr Carlier, CIRAD).

3. Undertake a study of the basicbiology of M. eumusaeand the epidemiology of Septoria leaf spot.More knowledge is required on the lifecycle, infection and sporulation condi-tions, relative importance of differentspore types and response to differentclimatic conditions of M. eumusae andSeptoria leat spot disease.

4. Develop a detailed understand-ing of the population structures of Mycosphaerella fijiensis,M. musicola and M. eumusae.Studies of the population structures ofM. fijiensis and M. musicola are inprogress at continental, regional andlocal scales in Africa, Latin America/Caribbean, and Australia (CRBP,CATIE, CIRAD, CRCTPP, COR-POICA). Such studies should be ex-tended, par ticular ly to south andSoutheast Asia. In India bananas aregrown over a wide range of latitudes,altitudes and climatic zones and undervaried farming systems. It is likely thatover time considerable diversity hasevolved within the populations of thedifferent pathogens (Dr Selvarajan,NRCB). The studies of populationstructure should include both molecu-lar and biological analyses. Populationstructures may be different underlarge-scale commercial systems com-pared to small plot systems becauseof different selection pressures (chem-ical vs. genotype). The sampling pro-tocol and methodology should beshared and standardized to ensurethat results from different laboratoriescan be compared.

5. Develop methods to follow the change in pathogen populations in response to selection pressure from new banana genotypes.It will be essential to monitor changesin pathogen populations in areaswhere new resistant hybrids arebeing grown on a large scale. Strate-

gies to ensure durable resistancemanagement may be defined on thebasis of population structure analysisand epidemiological studies. Suchstrategies will certainly integrate theuse of classic breeding and genetictransformation. A study is in progressin Cameroon (CRBP, CIRAD). This willenable the evaluation of a methodol-ogy, which includes population struc-ture and epidemiological analyses.Plot size and duration could be keyfactors in the study.

Several observations were reportedthat pathogen populations could evolveto overcome disease resistance.Yangambi km5 resistance to M. fijinen-sis has apparently been overcome inCameroon (CRBP) and possibly inCuba (Dr Pérez Vicente, INISAV).Paka resistance has been overcome inPolynesia (Dr Ful ler ton, Hor tRe-search), possibly in Cuba (Dr Pérez Vi-cente) and in China (Dr Jiang, SCAU).However, the identities of the clonesshould be checked. The resistance ofsome FHIA hybrids might also decline.There are reports of significant levelsof disease in FHIA-01 in Pacific Is-lands, India and Australia (Dr Fullerton,HortResearch; Dr Selvarajan, NRCB;Dr Aitken, CRCTPP) and in FHIA-03 inCuba (Dr Pérez Vicente, INISAV).However, Sigatoka spots could exist onthese hybrids because of high inocu-lum loads. Thus, changes in pathogenpopulations should be distinguishedfrom particular epidemiological effects.

6. Identify new sources of resistance to banana leaf diseases.Current breeding programmes are re-lying on a very narrow genetic basefor developing resistance (review byDr Tenkouano, IITA). There is exten-sive genetic diversity in banana bothbetween and within species in Asia.Investigations and evaluations of newmaterial for resistance against the dif-ferent leaf spot pathogens should beconducted in south and SoutheastAsia. There has been extensive col-lecting already done in Vietnam andin other countries. Evaluations shouldbe also carried out on existing collec-tions. Such analyses will help estab-

INFOMUSA — Vol 9, N° 2 PROMUSA IX

lish the relationship between resis-tances to the different leaf spotpathogens. Evaluations should in-clude information on the response ofdifferent banana varieties to thesepathogens either from artificial or nat-ural infections and epidemiologicalstudies.

7. Develop a better understandingof the mechanisms of resistance, in particular partial resistanceSeveral ‘mechanisms’ of partial resis-tance to M. fijiensis have been re-ported and are being evaluated for rel-ative efficiency in the control of thedisease (CRBP, CIRAD). It is as-sumed that partial resistance is likelyto be more durable than total resis-tance. The combination of different re-sistance mechanisms could improvechances of durability. Analysis for par-tial resistance in diploids is needed tointrogress resistance into diploid im-provement programs.

Some work has been done on map-ping and identification of genes con-trolling resistance (CRBP, CIRAD,CORPOICA). This should be ex-tended to allow the development ofmarker-assisted breeding systemsand genetic transformation. Geneticand molecular studies of pathogenicityshould be carried out concurrently.

8. Develop improved screeningmethods for evaluation of diseaseresistance in germplasm.The leaf pieces method, includingmethods for isolation, culture and in-oculum production for the differentpathogens (CIRAD), should be pub-lished and distributed to users. A firstprotocol has already been diffused. Astandardized scale for recording levelsof disease resistance will be devel-oped for in vitro screening. The use ofM. fijiensis toxins (or Juglone) maylead to a useful screening system (DrBusogoro, Univ. of Gembloux), but therole of toxins and the mechanism ofaction in pathogenicity should be de-termined. Studies are also needed toestablish whether toxins are involvedin Septoria leaf spot.

Other diseases and news

A new projectCIRAD, in collaboration with NRCB,MARDI and NERI (Denmark) and withthe help of INIBAP, submitted anINCO-DEV project to the EuropeanCommunity. Several of the prioritieslisted above constituted the objectivesof the project. If it is accepted, it willinitiate important collaborative work inIndia and Malaysia. Additional fundsshould be sought to extend studies toother Asian countries and to addressadditional priorities.

Blood diseaseThis fatal disease is caused by astrain of Ralstonia (Pseudomonas)solanacearum, which is closely re-lated to the organism that causesMoko disease. The pathogen is car-ried in infected plant material, andpossibly transmitted by flower feedingbats and insects. The disease hasspread through Indonesia and WestPapua, and recently was found in westPNG (Dr Williams, QDPI). All bananatypes seem to be susceptible, posingimmediate implications for food secu-rity in PNG and the loss of germplasmdiversity.

Speckle Mycosphaerella spp.In most cases, this pathogen is re-garded as of minor concern. However,its occurrence seems to be increasingin importance in hybrids. It is sus-pected that several species maycause the disease (Dr Car l ier,CIRAD). These should be identifiedand their distribution established. Thepopulation structure, too, may need tobe investigated. Detection of infectionshould be incorporated into screeningprogrammes. For the present, infor-mation is only available from naturalinfections, and an artificial inoculationsystem should be developed.

Freckle Phyllosticta/GuignardiaThis disease is important in Malaysiaand Philippines. Its relevance else-where in region is unknown.

ChinaA large number of diseases are re-ported from China (Dr Jiang, SCAU).Colletotrichum and Deightoniella canbe very severe. Black Sigatoka is evi-dent, but yellow Sigatoka is a moreimmediate concern. Septoria has notyet been recorded.

Fungicide resistanceIncreasing resistance to fungicidehas become a serious problem inmost commercial areas. Resistanceto benzimidazoles, triazoles and stro-bilurins, in particular, has been re-por ted (Dr Guzman, CORBANA; Dr Abadie, CRBP). A search for ef-fective alternatives is under way.Meanwhile, the incidence of growingfungicide-resistance stresses theneed for a commercially acceptabledisease-resistant banana.

Sigatoka symposiumThe advantages of holding the PRO-MUSA meeting back to back with theSigatoka symposium were discussed.Several meetings are proposed forCosta Rica and Cuba in 2001. Thepossibility of combining meetings isbeing investigated and the group willdecide where the next PROMUSAmeeting will be held.

PROMUSAParticipants felt that the principal ad-vantages conveyed by PROMUSA areprovided in the opportunities to attendthe meetings, interact with other peo-ple with similar interests and to be up-dated on the incidence of and re-search on different diseases withouthaving to wait for publication. This isparticularly useful for people at the im-plementation level in the field, who areoften working in isolation. The PRO-MUSA meeting allows them to under-stand priorities outside their immedi-ate region. Information exchange isalso seen as a very important functionof PROMUSA and the fact that groupsare able to decide how they communi-cate and interact.

The PROMUSA meetings should beused as a way to organize researchand to be more efficient (i.e. by setting

X PROMUSA INFOMUSA — Vol 9, N° 2

priorities). A number of activities forPROMUSA were suggested:• A database of organizations which

may be prospective project partnersshould be created and maintained

• Meetings between prospectivepartners should be facilitated(including the funding or support for planning visits)

• A close contact should beestablished with funding agents with PROMUSA acting as a coordinating body, settingpriorities and avoiding duplication

• Although PROMUSA is not seen to have a role in evaluating or refereeing project proposals, it could advise on the relevance of proposals in relation to overall priorities.

Report of thePROMUSA Fusariumwilt working group(FWWG)Par t icipants: Afr icano Kangire(KARI/NARO, Uganda), Altus Viljoen(FABI, South Africa), Aristoteles Piresde Matos (EMBRAPA/CNPMF, Brasil),

Julio Hernandez (ICIA, Canary Is-lands), Mauricio Rivera (FHIA, Hon-duras), Mary Wabule (KARI, Kenya),Mike Rutherford (CABI, UK), RandyPloetz (University of Florida, USA),Shin Chuan Hwang (TBRI, Taiwan),Suzy Bentley (CRCTPP, Australia) etZaag de Beer (ITSC, South Africa).Apologies from: Ken Pegg (QDPI,Australia), Liew Kon Wui (UniversitiSains Malaysia), Mike Smith (QDPI,Australia) and Natalie Moore (QDPI,Australia).Rapporteur: Suzy BentleyWorking group discussions coveredfour main areas: • Key issues for disease management

and current research priorities• Interactions between FWWG and

other working groups• Feedback on PROMUSA• Proposed communication strategy

for FWWG.

Key issues for diseasemanagement and currentresearch prioritiesThe key issues relating to the man-agement of Fusarium wilt and currentresearch priorities were developed at

the FWWG meeting held on 21-22October, 1999 in Kuala Lumpur,Malaysia (see PROMUSA No. 4, pub-lished in INFOMUSA Vol. 8, No. 2).These issues were: 1. Pathogen diversity2. Disease management strategies3. Epidemiology, and4. Other research issues of current

importance.Progress in each of these areas

was discussed and each issue was re-viewed to prioritize the recommendedaction required and to update re-search priorities (Table 1).

Research prioritiesThe group identified the standardiza-tion and evaluation of the plantlet-screening test for Fusarium wilt resis-tance as the most important researchpriority. A standard protocol for resis-tance evaluation needs to be devel-oped and assessed in different labora-tories, and also made available tobreeding programmes.

The development of a DNA-baseddiagnostic system for detection andidentification of all races and strainsof Fusarium oxysporum f.sp. cubense(Foc) directly from plant and soil wasalso considered a priority. A rapid

Meeting of the Sigatoka working group.

INFOMUSA — Vol 9, N° 2 PROMUSA XI

and accurate diagnostic test is nec-essary for the identification of dis-ease outbreaks, identification/certifi-cation of clean planting material andresearch into the epidemiology andecology of disease.

DatabasesThe establishment of a database con-taining a combined list of all of the iso-lates of Foc available through each ofthe major culture collections (CABI,UK; DPI, Australia; FABI, South Africa;

ICIA, Canary Islands; KARI, Uganda;TBRI, Taiwan; UF, USA; and USM,Malaysia) was deemed useful. A bibli-ography of fusarium literature (in eachof the key research areas l istedabove) and made available through

Issue Recommended action/research priority

1. Pathogen diversity

1.1 Genetic diversity •Training programme on VCG and DAF analysis for characterization of isolates of Foc

•Culture collection database (combine information from major collections)

1.2 Pathogenic diversity •Evaluate and standardize plantlet screening test

1.3 Diagnostics •Develop DNA-based diagnostic system for all strains of Foc

2. Disease management strategies

2.1 Education and awareness •General Fusarium wilt fact sheet—multilingual for wide distribution (in preparation)

•Use of farmer demonstration plots to be encouraged

2.2 Quarantine measures to prevent pathogen spread •Adapt general fact sheet to suit local situations/regulations and target quarantine officers

•Develop standard protocols for disinfecting machinery, implements, footbaths etc

2.3 Clean planting material •Education on the benefits of tissue culture plants

2.4 Development of resistant varieties •Selection and evaluation of resistant germplasm

•Plantlet screening test required for resistance evaluation

•Banana breeding programme in Asia

2.5 Adoption of disease resistant varieties •Training in utilization/application of IMTP III protocols

•Use of farmer demonstration plots recommended

2.6 Chemical/biological control •SAR agents to boost host resistance

•Non-pathogenic F.oxysporum, bacteria etc.

2.7 Cultural control •Soil amendments

•Annual cropping

3. Epidemiology

Several research opportunities exist, including investigations into the temporal and spatial development of disease, focal development of disease, pathogen survival in infected plant material, soiland debris, and alternative host studies.

4. Other research issues

4.1 Plantlet screening test •High priority!

•Standardize and evaluate Dr Liew’s protocol in different laboratories worldwide

•Validate test with field reaction data

•Initiate testing centre for exotic isolates (at CABI)

•Make protocol available to breeding programmes

4.2 Collect and evaluate native germplasm for reaction to Foc •National programmes to submit material to ITC with material acquisition agreement

•Verification of the identity of germplasm

4.3 False Panama disorder •False Panama in Canary Islands and South Africa

•Matooke wilt in Uganda

•Combined fact sheet will be prepared and distributed to increase awareness of this problem

Table 1. Priorities for Fusarium wilt disease management and research.

XII PROMUSA INFOMUSA — Vol 9, N° 2

the INIBAP Web site was also consid-ered to be a useful resource.

Interactions between FWWGand other working groupsThe following issues were consideredto be a priority for interaction withother PROMUSA working groups:

Genetic improvement workinggroup• Identification of additional

resistance in land races and hybrids• Standardization and evaluation

of the plantlet screening test• Collate existing data

for resistance of wild banana typesin germplasm collections

• Obtain a better understanding of the mechanisms of resistance to Fusarium wilt

• Identification of markers for resistance to Fusarium wilt

• Establishment of a banana breeding programme in Asia.

Nematology working group• Inform the Nematology working

group of the developments with the Fusarium wilt plantlet-screeningtest. Combining/coordinating the Fusarium wilt plantlet-screeningtest with the nematode resistancetest is a possibility.

Feedback on PROMUSA• The structure of PROMUSA

(the relationships among theworking groups and between the working groups and the Steering Committee wasunclear to some, simple terms of reference covering the aims of the working groups withinPROMUSA, the role of the secretariat and the role of the working group convenor may be useful).

• A review mechanism for the working groups and a procedure for nominating new working groups (e.g.Extension) was suggested.

• A more rigorous reporting system for the working groups,

e.g. twice-yearly reporting against action items and milestones added to action items, was also suggested.

Proposed communicationstrategy for FWWGIt was proposed that better communi-cation within the FWWG could beachieved by: • Using the PROMUSAFUS

listservers• Monthly research updates

submitted by different FWWG members (distributed on the PROMUSAFUS listserver) collated into a yearly newsletter(issued on the PROMUSAWeb site).

It was proposed that the next Fusariumwilt working group meeting be hostedby Dr Altus Viljoen (FABI) in SouthAfrica in 2002.

Report of thePROMUSANematology workinggroup (NWG)Participants: Guy Blomme (INIBAP,Uganda), Mieke Daneel (ITSC, SouthAfrica), Dirk De Waele (KUL, Bel-gium), Carine Dochez (IITA, Uganda),UK), Imelda Kashaija (KARI/NARO,Uganda), Thomas Moens (COR-BANA, Costa Rica), Tony Pattison(QDPI, Australia), Jean-Louis Sarah(CIRAD, France), K. Soorianathasun-daram (TNAU, India), Inge Van denBergh (VASI, Vietnam). Apologisesfrom Julie Stanton (QDPI, Australia).Rapporteur: Dirk De Waele

Research resultsEach members of the Nematologyworking group,provided an outline ofthe results of nematology work in theirresearch group. Since the last meet-ing in Cameroon (1998), research car-ried out may be classified into threemain areas:

Biodiversity in nematode communitiesStudies are ongoing on the interspe-cific and intraspecific diversity ofRadopholus similis and Pratylenchuscoffeae (Australia, Costa Rica, Viet-nam, Cameroon and France). Fieldsurveys can reveal the existence ofsecondary species, which may be apotential threat to banana produc-tion. For instance a new species, R. musicola, has been found in Aus-tralia. A total of 33 species in 18 gen-era have been identified in Cameroon,whilst surveys suggest that R. similismay be absent from banana planta-tions in the Vietnam. Meanwhile,using different molecular techniques,CIRAD has illustrated that R. similispopulations may be divided into twogenomic groups, one cover ingCameroon, Costa Rica and Australia,the other extending from Côted’Ivoire to Uganda.

Impact of nematodes on bananasThe correlation between root damageand yield loss is being studied inCosta Rica, Vietnam and Cameroon.Concern was expressed at the resultsof a recent survey, which indicatedthat most subsistence farmers inSouth Africa are using the same ba-nana variety. What’s more, productionin Mozambique, which represents animportant source of material for SouthAfrica banana growers, has plum-meted.

Screening, mechanisms of resistance, transformationScreening for resistance in banana va-rieties is occurring in numerous coun-tries. In Vietnam recently collected vari-eties are being tested. In Uganda, anew screening technique has been de-vised using single root inoculation. Invitro screening is ongoing at KUL.Studies of phenolics and the histologi-cal morphology of roots are being car-ried out in India and Cameroon to in-vestigate the mechanisms of nematoderesistance, specifically in Yangambikm5. Meanwhile the use of modeltransgenic plants, e.g. Arabidopsis, indeveloping nematode resistance in ba-nanas is being investigated at KUL.

INFOMUSA — Vol 9, N° 2 PROMUSA XIII

Research prioritiesA number of new research prioritieswere identified. Former priorities havebeen rearranged into three main axis: • Nematode communities,

including biodiversity• Damage and yield

loss potential of populations

• Resistance screening: methods,sources, mechanisms.

Link with Geneticimprovement working groupNWG proposed a table displayingputative needs by plant breeders(Table 2). The first three columns rep-

resent different categories of work.The last column is the ‘offer’ of possi-ble input by nematologists.

The role of the NWG andPROMUSADiscussions were held on the function-ing of the NWG and of PROMUSA as

Members of the Nematology working group.

IPM Classical Molecular Present knowledge

What do plant breeders need from the NWG?

➣ Host status:

•resistance +++ +++ +

•tolerance +++ -

➣ Sources of resistance (useful for breeding) +++ +

➣ Mechanisms of resistance + (+) +++ +

➣ Genetic basis inheritability ++ ++ -

➣ Markers (molecular) +++ + -

➣ Genes (proteins) (+) +++ -

Tools➣ In vitro screening +++ +++ + ++

➣ Greenhouse screening +++ +++ + ++

➣ Field screening +++ +++ + ++

➣ Highly sensitive screening +++ -

Table 2. Links with the Genetic improvment working group.

XIV PROMUSA INFOMUSA — Vol 9, N° 2

a whole. Although the members of theNWG have been very active, there hasnot been much collaboration within theNWG nor between the NWG and thebreeders. Communication obviouslymight be improved. Through discus-sions an attempt was made to addressthese problems and to define the cur-rent research priorities and needs forthe forthcoming year.

The role of the convenor was de-bated. Dirk De Waele was chosen asthe new convenor. The membersagreed that the convenor alone cannotmake the NWG function, all membershave to participate and to be activelyinvolved. They also agreed that theconvenor should not cause a ‘bottle-neck’ for communication externally (i.e.with the secretariat/board, others WG).

In the discourse on PROMUSA,conclusions were made that: • PROMUSA should act as facilitator

of communication (for people whoare willing to communicate) and bring about better collaborationand the exchange of information.

• PROMUSA should be a facilitatorfor working groups in the accessof funding (not providing fundsitself) and enable bettercommunication for project building.To contribute to PROMUSA, the

NWG will: • improve communication by updating

the mailing list, sharing informationon the Internet (abstracts of publications, methodologies,overview of ongoing research),exchanging post-graduate studentsand research associates,exchanging ‘materials’, etc.

• gather present knowledge and establish three databases: on nematode communities,biodiversity (J.-L. Sarah), damageand yield loss potential (R. Fogain),sources and mechanisms of resistance (D. De Waele)

• participate in IMTP III by providing a list of 10 genotypes to be tested in different places (R. Swennen and all members), by sendinginformation to the mailing list(allowing anyone with an interest to join) and through field trials (15replications, using plants from

naturally infested and nematicide-controlled fields)

• plan a meeting to follow theNematological Congress of NSSA(South Africa, May 2001)—‘Workshop on genetic improvementof Musa for nematode management’(2-3 days).

Report of thePROMUSA Virologyworking groupPar ticipants: Marie Line Caruana(CIRAD, France), James Dale (QUT,Australia), Martine Delanoy (Univ. ofGembloux, Belgium), Glyn Harper(JIC, UK), Bertrand Helliot (Agricul-tural University, Gembloux, Belgium),John Hu (Univ. of Hawaii , USA),Jackie Hughes (IITA, Nigeria), RogerHull (JIC, UK), Lawrence Kenyon(NRI, UK), Phillipe Lepoivre (Univ. ofGembloux, Belgium), Ben Lockhart(Univ. of Minnesota, St. Paul, USA),Gerhard Pietersen (ARC-PPRI, SouthAfrica), Helena Reichel (CORPOICA,Colombia), H.J. Su (National TaiwanUniversity), John Thomas (DPI, Aus-tralia).Rapporteur: Jackie Hughes

BSV and other virus (potex) in germplasm movement and exchangeDiscussions were held on the func-tioning of PROMUSA, of the WorkingGroup and the function of the con-venor. A new convenor was chosen,Jackie Hughes, and appreciationshown for the contribution of RogerHull, the outgoing convenor. Presenta-tions on the activities of the variousresearch groups represented in theWorking group were made on eachvirus. A detailed summary was madeof the current diagnostics used at theINIBAP Virus indexing centres as wellas those available to researchers andcommercial organizations.

Banana bunchy top virus (BBTV)Sequence variability of BBTV, particu-larly in Asia, was recognized to be

wider than previously thought. Accord-ing to symptom expression, differentbiological variants exist. Indicators forresistance in mature plants have beenidentified. Also a number of transgenicplants have been developed. At leastone construct is proving to be resis-tant but not immune to the virus. Theknowledge of the molecular biology ofBBTV is well advanced and a range ofmicrosatellite DNA sequences associ-ated with Asian isolates are estab-lished.

Banana bract mosaic virus(BBrMV), genus PotyvirusQueensland University of Technologyreported that Cavendish and Blug-goe varieties genetically modifiedwith coat protein constructs ofBBrMV are now available for testing.Field-testing is planned in the Philip-pines. The sequencing of genes fromdifferent samples of the virus (includ-ing CP and Nib) has revealed nomore than 5% genetic variation atthe nucleotide level in CP and Nib. Aconstruct has been developed with‘average’ variation. Apart from knownoccurrences in the Philippines, Indiaand Sri Lanka, the virus has beendetected once in Western Samoaand rarely in Vietnam. These iso-lates, however, did not display typicalsymptoms.

Queensland Department of PrimaryIndustry has identified a BBrMV iso-late with more than 10% genetic varia-tion, which is significant to the devel-opment of transgenic material. Acomplete range of serological andPCR-based diagnostics are available.

Cucumber mosaic virus (CMV)Although CMV is widespread, it is notgenerally a serious disease. Howeverwith the rise in number of tissue-cul-tured plants in banana production inTaiwan and China, CMV is causingmore problems. Mixed infections ofCMV and banana mild mosaic viruscan also produce more severe symp-toms. CMV strains infecting bananahave been characterized in Hawaii,Taiwan and China. Transgenic plantswith resistance to CMV infection areunder development.

INFOMUSA — Vol 9, N° 2 PROMUSA XV

Banana mild mosaic virus (BanMMV)The Ducasse filamentous virus strainisolated from Pisang Awak (ABB) hasbeen totally sequenced. It seems tobe a new virus type between potex,fovea and alexiviruses.

The filamentous virus identified inco-infection with BanMMV is serologi-cally related to the filamentous parti-cle infecting a broad range of Musagermplasm, particularly cooking ba-nanas, and 11% of the GuadeloupeCIRAD banana collection.

The primers defined from a con-served CP zone of Ducasse virus, andpoly A, are used in order to study thediversity of the virus in this collectionand in a part of the INIBAP germplasm.Because no, or only mild, symptomsare associated with this virus in singleinfection, no relevant information isavailable in terms of impact and epi-demiology.

A joint proposal between Gembloux,CIRAD, CORPOICA and the Univer-

sity of Costa Rica, INCO, was submit-ted in September within the frameworkof PROMUSA in order to evaluate therisk associated with the disseminationof this virus alone, or in co-infectionwith BSV or CMV. A new PhD studentis working at Gembloux to character-ize the Colombian strain and to de-velop a reliable diagnostic kit.

Banana streak virus (BSV)Discussions examined the clear evi-dence that BSV infection arises fromviral sequences integrating into theMusa genome. Tissue culture is a fac-tor that triggers episomal expressionof integrated BSV sequences. Both‘activatable’ (episomally-expressible)and ‘non-activatable’ (non-episomally-expressible) BSV sequences are inte-grated in the Musa genome.

One act ivatable BSV integrant(BSV-OL) is associated with the MusaB genome and not with the Musa Agenome. Three other episomal BSVspecies (BSV-GF, BSV-IM and BSV-

MYS) are integrated in the Musagenome. Like BSV-OL they appear tobe associated with the Musa Bgenome. Initial evidence suggests thata series of other BSV integrants alsooccur in Musa. However, these haveyet to be characterized.

Episomally-expressible (BSV-OL)and possibly episomally-expressibleviral integrants (BSV-GF, BSV-IM)occur widely in plantains (AAB) andbananas (AAA) in Central and SouthAmerica. The discussions concludedthat these BSV species are not intro-duced into new areas in tetraploidAAAB hybrids produced by variousMusa breeding programmes. BSV-OLand BSV-GF infection in AAA dessertbananas in Costa Rica, Ecuador andVenezuela result from pre-existing la-tent infection or from virus transmis-sion from plantains.Recommendations were made that: • BSV indexing should be routinely

done in commercial AAA bananatissue culture production

Virus Diagnostic(s) Comments

BBTV ELISA Commercial antisera detects known strains

PCR Sensitive but strain specific

BBrMV Miniprep + ISEM Polyclonal antisera and recombinant antisera available*

ELISA

Standardization with miniprep + ISEM

BanMMV Miniprep + ISEM Polyclonal antiserum available *

Standardised method

AbaMV Miniprep + ISEM Polyclonal antiserum available *

Standardized method

CMV ELISA Commercial antiserum available detects both serotypes

Standardized method – same antiserum

BSV (épisomal) Miniprep + ISEM Poly-polyclonal antiserum available* Detects episomal virus. Possible problems

with strain variation. Possible problem with antisera and primers on variation

IC-PCR

Standardized method miniprep + ISEM

BSV (activatable intégrant) PCR Strain specific. Depends on strain sequence information.

Other viruses Miniprep + EM Detects presence of rod-shaped viruses and, coupled with antisera0*

detects previously unrecognized viruses.

More difficult with low concentration isometric viruses.* Not available for commercial detection.

° Some antibodies available against BDBV.

Current situation on Musa virus diagnostics and their availability

XVI PROMUSA INFOMUSA — Vol 9, N° 2

• Research needs to be done immediately on the role of mealybugs in BSV transmission in the field.Episomal expression of BSV inte-

grants in the Musa B genome appearsto require the presence of the Agenome. This model is supportedfrom data from similar phenomena intobacco and petunia. ImmunocapturePCR (IC-PCR) is ten times more sen-sitive than ISEM in detecting BSV.More research is needed to resolveoutstanding questions about the relia-bility of the technique.

Other virusesA brief discussion was held on otherrod-shaped viruses found in Musagermplasm. In particular potyvirus-like par ticles have been found ingermplasm from Sri Lanka. Isometricvirus particles have also been foundin Musa spp. in Nigeria. The virus,tentatively named banana diebackvirus (BDBV, genus ? Nepovirus)causes severe dieback symptomsand appears to spread slowly in thefield. The production of diagnostics(polyclonal, monoclonal, primers) isin progress.

Functioning of PROMUSAThe final part of the discussions fo-cussed on the functioning of PRO-MUSA. PROMUSA has facil itatedcommunication within the group. How-ever there is a need to strengtheninter-working group linkages. A sug-gestion was made to set up a ‘con-venors group’ to enable information,research results and needs to be dis-

seminated to members of the appro-priate groups. A request was alsomade for a ‘fire-walled’ Internet site tobe set up to allow members of workinggroups to deposit information, such asincomplete sequence data, for the useof the working group alone. There isalso a need to invite virologists fromcountries such as India and China totake part in the working group.

Participants of the Virology working group.

Priorities for virology research involving geneticimprovement• Development of reliable diagnosis of BSV, using appropriate diagnostics

in an informed manner, by developing a better understanding of BSVdiversity and through education on the significance of A and B genome

• Production of a PROMUSA pamphlet on current procedures for virusdiagnosis

• Better understanding of B genome heterogeneity• Better understanding of the contribution of the A genome in activating

virus integrants in advanced breeding lines• Mechanism to silence BSV integrants in the genome• Research into the geographical diversity of BSV vis-à-vis movement of

germplasm, particularly with respect to epidemiological information andrisk assessment

• Development of resistance screening methods• Securing supplies of diagnostics• Research into the possibility and applicability of producing virus-‘free’

plantlets, particularly with respect to BanMMV and BSV.

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