New Wheats for Sustainable Future

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New Wheatsfor a Secure,

Sustainable Future

Timothy G. Reeves, Sanjaya Rajaram,

Maarten van Ginkel, Richard Trethowan,

Hans-Joachim Braun, and Kelly Cassaday


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M aarten van Ginkel, head of bread w heat

breeding at CIM M YT, holds one of the

large-spiked w heats (right) that promise

to raise yields in w heats. On the lef t he

holds a normal w heat spike. (See page 7.)


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29

New Wheats for

a Secure, Sustainable

Future

Timoth y G. Reeves, Sanjaya Rajaram, Maar ten v an Ginkel,

Richard Trethow an, Hans-Joachim Brau n, and Kelly Cassaday*

* All au thors are staff of CIMMYT. T.G. Reeves is Director General; S. Rajaram is Director

of the Wheat Program; M. van Ginkel is Head , Bread Wheat Breeding; Richard

Trethow an is a Wheat Breeder; H.-J. Braun is a Wheat Breeder (based in Tur key); andKelly Cassaday is a Writer/ Editor. An earlier version of this paper w as presented at the

9th Wheat Breeding Assembly, 27 September-1 October, 1999, University of Southern

Queensland , Toowoom ba, Queensland , Australia.


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CIMMYT (www.cimmyt.mx or www.cimmyt.cgiar.org ) is an internationally fund ed, nonp rofit

scientific research and training organization. Head quartered in Mexico, the Center works w ithagricultura l research institutions worldw ide to improve the p rodu ctivity, profitability, and

sustainability of maize and wh eat systems for poor farmers in developing countr ies. It is one of 16

similar centers sup ported by the Consu ltative Group on International Agricultura l Research

(CGIAR). The CGIAR comprises about 60 partner countr ies, intern ational and regiona l

organizations, and private found ations. It is co-sponsored by the Food and Agriculture

Organ ization (FAO) of the United Na tions, the Interna tional Bank for Reconstru ction and

Developm ent (World Bank), the United Na tions Developm ent Programm e (UNDP), and th e United

Nations Environment Programme (UNEP). Financial support for CIMMYTs research agenda also

comes from m any other sources, includ ing foun dations, development ban ks, and pu blic and private

agencies.

CIMMYT supp orts Future H arvest, a public awareness campaign th at buildsund erstanding about th e importance of agricultura l issues and international

agricultura l research. Futu re H arvest links respected research institutions, influential p ublic figures,

and leading agricultural scientists to und erscore the w ider social benefits of improved agriculture

peace, prosperity, environmental renew al, health, and the alleviation of hu man suffering

(www.futureharvest.org).

Interna tional Maize an d Wh eat Imp rovem ent Cen ter (CIMMYT) 1999. Responsibility for this

publication rests solely with CIMMYT. The designations employed in the presentation of material

in this pu blication do not imp ly the expressions of any opinion w hatsoever on th e part of CIMMYT

or contribu tory organ izations concerning the legal statu s of any countr y, territory, city, or area, or of

its authorities, or concerning the delimitation of its frontiers or boun daries.

Printed in Mexico.

Correct citation: Reeves, T.G., S. Rajaram, M. van Ginkel, R. Trethow an, H -J. Brau n, an d K.

Cassa day. 1999.New Wheats for a Secure, Sustainable Future. Mexico, D.F.: CIMMYT.

Abstract: This paper reviews strategies used by CIMMYT and its partners to develop su stainable

wh eat prod uction systems for favored and marginal areas. These strategies aim to a chieve an

optimal combination of the best genotyp es (G), in the right environments (E), und er ap propriate

crop m anagem ent (M), and app ropriate to the needs of the people (P) wh o mu st implement and

man age them . The first section of the pap er presents new options for raising w heat yield potential

and discusses research on disease and stress tolerance, which is aimed at protecting yield p otential

in farmers fields (with special emp hasis on drou ght tolerance). Next, advances in dur um wh eatyield p otential are reviewed ; these advances may p rove particularly valuable in m arginal

environments. Other w heat research initiatives for ma rginal environments are d escribed as w ell.

This is followed by a review of the role of biotechnology in wheat improvemen t, research on w heat

quality, and initiatives in crop an d natur al resource managem ent research. The pap er conclud es

with a su mm ary of the latest data on th e global impa cts of wheat research and a discussion of

trends that could affect whether and how th is imp act is maintained.

ISBN: 970-648-040-4

AGROVOC descriptor s: Whea ts; Triticum; Ha rd w heat; Winter crops; Spr ing crops; High yield ing

varieties; Hybrids; Plant production; Production policies; Food production; Food security; Plant

breeding; Plant biotechnology; Nutrient improvement; Drought resistance; Pest resistance; Disease

resistance; Crop management; Resource management; Sustainability; Innovation adoption; Yield

increases; On farm research

Additional keywords: CIMMYT; Participatory research

AGRIS category codes: E14 Developmen t Economics and Policies; F30 Plant Gen etics and Breeding

Dewey decimal classificataion: 338.162ii


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Contents

iv Acknow ledgm ent s

1 New Wheats for a Secure, Sustainable Future

2 Agriculture: An Agent of Change

3 Prerequisites for Sustainable Agriculture

4 Breeding Wheats for Lasting Food Security

4 Options for Increasing Yield Potential

6 Gen e p ools of w in ter and sp rin g h exap loid w heats

6 In trogressin g sp rin g an d win ter wh eat gen e p ools

6 Ch in ese w heats: A w ellsp rin g of d iversity

6 Hybrid wheats7 Landraces

7 Improved plant ideotype

7 Phenological traits

7 Physiological traits

8 Synthetic w hea ts: Deliver ing diver sity to p lan t breeder s

8 Alien su bstitu tions and translocations

9 Protecting Yield Potential: The Role of Resistance to

Pathogens and Pests11 M oving beyond Marginal Yields in Marginal Environments

11 Breed ing for d rought tolerance

14 Higher yield ing durum wheats

15 Regional resea rch on w hea t for marg inal environments

16 Improvements in Wheat Quali ty

17 Biotechnology and Wheat Improvement: An Example ofCollaboration

18 Crop and Natural Resource M anagement Research

19 Improved input use efficiency

19 Bed planting systems

20 Farm er participatory research

21 Information Management Tools for Sustainable Systems

22 Conclusions

24 A n ew research parad igm for n ew research im p acts

24 The shape of things to come

27 References

ii i


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Acknowledgments

The authors are grateful to man y colleagues within CIMMYT who

contribu ted information for this pap er. Special thanks go to staff ofthe Wheat Program, as much of their research is d escribed here,

includ ing A. Mu jeeb-Kazi, I. Ortiz-Monasterio, J. Pea , W. Pfeiffer,

M.P. Reynolds, R.P. Singh, K.D. Sayre, and P. Wall. L. Harrington

and J. White of the N atural Resources Group , and A. McNab an d

D. Poland of Information Services, also generou sly provid ed

information for th is pap er. We than k the CIMMYT design section

for layou t and prod uction of the pu blication.

None of the work reported here would have been possible

withou t the continuining sup port of CIMMYTs investors, themem bers of the CGIAR. Amon gst those we p articularly than k our

core investors.

iv


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2

Agriculture: An

Agent of Change

The role of more prod uctive, profitable

maize and wh eat systems in fostering

food secur ity, generating local

employment, raising local incomes,

and thus alleviating poverty mu st not

be un derestimated. A recent report

(UNDP 1997) emp hasizes that

agricultural research is the central

means of achieving those goals:About th ree-quarters of the worlds

poorest people live in ru ral areas,

depend ent on agricultural activities

for their livelihood s. For these peop le,

pro-poor growth m eans raising

agricultu ral prod uctivity, efficiency,

and incomes. The report p oints out

wh y agricultu re can succeed w here

other initiatives migh t fail: Raising

the productivity of small-scale

agricultu re does more th an benefit

farmers. It also creates emp loyment on

the farm an d offand redu ces food

prices. The poor benefit most, because

about 70% of their consum ption is

food, mostly staples, and regular

sup plies and stable prices can greatly

redu ce the vulnerability of the poor.

Strong support to small-scaleagricultu re was at the core of the most

successful cases of pover ty

reductionsuch as China in 1978-85,

Malaysia since 1971, and Ind ia in the

early 1980s.

In these circum stances, the

challenges for researchand the

opp ortun ities to alleviate mu ch

hu man su fferingare clear. We will

have to develop the innovations that

make it possible for peop le to benefit

from m ore efficient, low-cost systems

for food prod uction. These systems

mu st fun ction w ithout m ining the

natu ral resources on which agriculture

dep end s. They are needed urgen tly in

favored as w ell as less favored

agricultu ral areas.In this paper, we review strategies

used by the International Maize and

Wheat Imp rovement Center

(CIMMYT) and its par tners to develop

sustainable wheat1 production

systems for favored an d m arginal

areas. These stra tegies aim to achieve

an op timal combination of the best

genotypes (G), in the rightenvironments (E), un der ap prop riate

crop m anagem ent (M), and

app ropriate to the needs of the peop le

(P) wh o mu st imp lement and manage

them (Reeves 1998, 1999). Each

variable in th is GxExMxP

sustainability equation is add ressed

in the sections that follow. After furth er

defining what w e mean by

sustainable technology, we:

Review new options for raising w heatyield poten tial.

Discuss research on d isease and stresstolerance, wh ich is aimed at

protecting yield p otential in farm ers

fields. We give special emp hasis to

drought tolerance.

Describe advances in du rum wh eatyield p otential wh ich may p rovepar ticularly valuable in marginal

environments.

1 In this paper we focus on strategies

related to wheat, although CIMMYTs

research mand ate encompasses maize as

well. We also give greater attention to

wh eat genetic improvem ent than to

crop and natu ral resource management

research, but readers shou ld be ad visedtha t CIMMYT engages in a great d eal of

crop and resource management

research, for w heat as w ell as maize. Fora general overview, see our annual

report, CIMMYT in 1998-99:Science to

Sustain People and the Environment.


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3

Provide an overview of other w heatresearch initiatives for marginal

environments.

Review the role of biotechnology in

wh eat improvement. Describe recent research on w heat

qua lity. For m any p oor farmers, an

increase in wh eat quality means a

correspond ing increase in income.

Briefly review recent initiatives incrop an d natural resource

management research in w heat.

We conclude by su mm arizing the

latest data on th e global impacts of

our w heat research and by d iscussing

trends that could affect wh ether and

how this imp act is maintained into

the future.

Prerequisitesfor Sustainable

Agriculture

To be susta inable, farm ing system s

mu st be biologically sensible,

economically viable, environmentallysound , socially acceptable, and

politically su pp ortable (Reeves 1998,

1999):

Sustainable farming systems m ust bebiologically sensible. For examp le,

the choice of crop(s), their

management, and the level of

intensification m ust be consistent

with the biophysical realities of the

farming system.

Sustainable farming systems m ust beeconomically viable at the farm and

national levels. Poor farmers cannot

invest in systems that w ill not

prod uce reasonable yields and (even

better) cash income, now and in the

future. At the national level, the

reality in most d eveloping countries

is that econom ic well-being and

developm ent are almost invariably

based on prod uctive and profitable

agriculture, the engine room of

subsequent industrialization.

Sustainable farming systems mu stbe environmentally soun d.

Economic success in agriculture

cannot come at the expense of our

soils, air, water, landscapes, and

indigenous flora and fauna.

Sustainable farming systems mu stbe socially acceptable. They m ust be

app ropriate to the people who,

relying on their own meager

resources, are responsible for

implementing and m anaging them.

The need for socially acceptable

systems imp lies the need for a better

und erstanding of farmer andcomm unity needs and values, as

well as better targeting of

technology to m eet local conditions.

Finally, sustainable farming systemsmu st be politically sup por table.

Political supp ort depend s largely on

successfully m eeting the first th ree

requirements of sustainability. If

econom ic growth is catalyzed by

agriculture within anenvironmentally sound , socially

acceptable framew ork, p oliticians

will continue to view agriculture as

justifying su pp ort.

All of these compon ents combine

to form the w hole: sustainable

agricultu re. If one is neglected, it can

seriously redu ce the rate and extent of

progress toward s sustainability and

food security.


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pattern s and their implications for

agricultu re. There is limited scope to

open n ew land for crop p roduction, and

there is an even more u rgent need to

protect land (in p articular, marg inalland) from inapprop riate uses. In recent

decades developing coun tries have

fortunately relied more on increased

yields than on an expansion of cropped

area to feed th eir pop ulations. Between

1961 and 1990, yield increases accounted

for 92% of the add itional cereal

produ ction in the d eveloping w orld

(Reeves, Pinstrup-And erson, and

Pand ya-Lorch 1997). When farm ers in

stable, high prod uction environments

obtain better yields, the need to intensify

prod uction in fragile agricultural

systems is redu ced , offering a mu ch

more sustainable app roach to meeting

long-term d emand for cereal prod uction

in developing coun tries.2 Because

higher y ield ing lines are frequen tly bred

to use inpu ts such as n utrients andwater m ore efficiently, higher yields are

not obtained a t a higher cost to the

environment. As our CIMMYT

colleague, Nobel Laureate Norm an

Borlaug, has said, The only w ay for

agricultu re to keep p ace with p opu lation

and alleviate world hu nger is to increase

the intensity of prod uction in those

ecosystems that lend themselves tosustainable intensification, while

decreasing intensity of produ ction in the

more fragile ecologies (Borlaug an d

Dowswell 1997).

The selection of segrega ting

pop ulations and consequent yield

testing of advan ced lines is param oun t

for iden tifying high yield ing, inp ut

responsive wheat genotypes. Theincrease in yield potential of CIMMYT

cultivars d eveloped since the 1960s is

show n in Figu re 1 (K. Sayre, per s.

comm.). The d ata d o not ind icate that

we are app roaching a yield p lateau,

and the p erformance of recently

released lines su ch as Attila an d

Baviacora, and ofLr19-derived Veery,

indicates that yield poten tial has beenfurther enhanced.

With y ield , a complex trait still

not w ell un derstood genetically or

ph ysiologically, the use of proven,

high yield ing sources, as well as

genetically d iverse germp lasm, will

continu e to be param oun t for

increasing yield potential. Genetic

diversity and the opp ortun ity for itsrecombination th rough crossing will

be imp ortant to break und esired

linkages an d increase the frequency

2 For example, if India were sudd enly

required to produce its current w heat

harvest u sing the technologies of 30

years ago, Indian farmers wou ld have tobring more than 40 million hectares of

add itional land into prod uction. The

wh eat varieties developed in the past

three decades were instrumen tal in

preventing d amage to areas that are not

well suited to agriculture.

10,000

9,600

9,200

8,800

8,400

1965 70 75 80 85 90 95Variety year of release

Grain yield kg/ha at 12% H20

Figure 1. Grain yield trend for semidwarf bread

wheat lines developed at CIMMYT since 1966,

under conventional planting, average for 1997,1998, and 1999 crop cycles at CIANO, Cd.

Obregn, Mexico.

Source: K.D. Sayre, CIMMYT.

Yield = -6.22*+104+36.05x(kg/ha/year)r2 = 0.772

Annual yield increase = 0.39%/year


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of desirable alleles. Futu re

breakthroughs in yield potential are

likely to come from such genetically

d iverse crosses. Examples are given

below, along with a d escription ofother efforts to raise both sp ring and

winter w heat yield p otential.

Gene Pools of Winter andSpring Hexaploid WheatsThe variability cur rently available

among spring and winter hexaploid

wheats is still extensive. New h igh

yield ing sources from w ithin theCIMMYT Bread Wheat Program and

from arou nd the world are iden tified

and intercrossed. For examp le, high

yield ing spring wh eat lines from South

Asia and China are regu larly

intercrossed w ith the h ighest yielding

lines identified in Mexico, followed by

selection for typ es sup erior to either

paren t, carrying all desirable genes.

Likewise elite w inter w heats are

intercrossed. Considerable progress

can still be mad e in this way as yield is

controlled by many genes and the

optimal combinations of these genes

for any particular environmen t may

not yet have been realized .

Introgressing Spring and

Winter Wheat Gene PoolsBy introgressing genetic variability

from w inter wheats, breeders have

considerably augmented the yield

potential of spring w heats. The Veery

wh eats, developed from crosses of

CIMMYT spring w heats and Russian

winter wheat, represented a quan tum

leap in spring wh eat yield an d w ide

adaptation du ring the 1970s and 1980s(CIMMYT 1986) (their cont ribu tion to

drough t tolerance is d iscussed later).

More recently, the spring bread wh eat

Attila, developed from crosses with

western European an d US winter

wheats, has rapidly gained ground on

the Indian subcontinent. New evidence

indicates that yield poten tial in w interwheat m ay also benefit from crosses

with high yielding spr ing wheats.

Chinese Wheats: AWellspring of DiversityBefore the mid-1980s, only a limited

amoun t of wheat germplasm from

outside China was available to

Chinese breeders. Since the mid-1980s, CIMMYT and Chinese

scientists have w orked together to

benefit from th e diversity in each

others wh eat germp lasm. More

than 100 Chinese varieties conta in

CIMMYT germp lasm, and u p to

20% of new CIMMYT spring wheats

have Chinese wh eats in their

ped igrees. Apart from its resistance

to biotic pests such as scab and

Karnal bun t, mod ern Chinese

germp lasm offers new alternatives

for raising the yield p otential of

wheat; yields of elite Chinese

wheats in China can exceed 10 t/ ha.

Hybrid WheatsThe expression of heterosis for yield in

wh eat can be high. Althou gh it has

been well documented, heterosis has

not been exploited commercially to

any great extent. Hybrids offer the

unique opp ortunity of combining

different gene p ools in th e prod uction

of the F1 hybr id. Because h eterosis is,

to some extent , a function of genetic

distance, CIMMYT is well positioned

to exploit this need for geneticdiversity. During th e past three years,

CIMMYT hybrids h ave p rodu ced

yields that are 15-20% higher th an

those of comm ercially grown cultivars


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in Mexico, and levels of heterosis of

a similar m aximu m size have been

reported . The difficulty of prod ucing

F1 seed in a cost-effective way

remains the g reatest limitation to th eexploitation of such hybrid s, but

CIMMYT breeders expect to resolve

this issue by introgressing

outcrossing traits.

LandracesMany high yield ing CIMMYT

wh eats have a considerable num ber

of landraces in their p edigrees. Acoefficient of parentage analysis

reveals that on average CIMMYT

advanced lines contain as man y as

50 land races in their gen etic history.

Breeding p rograms have still not

exploited a ll of the yield-controlling

genes available in landraces.

Landraces may also prov ide novel

sources of adaptation, wh ich w ill

allow breeders to select more stable,

high yielding lines. As yields

increase, consumer p references will

also turn to increased qu ality and

taste. Here, locally preferred

landraces can play a very new and

exciting role.

Improved Plant Ideot ypeCIMMYT breeders are u sing

increased know ledge of the

physiological bases of yield to d efine

a range of optimal wh eat plant

ideotypes. We are examining p lants

with large spikes, wh ich contain

man y grains per sp ikelet (see photo,

inside front cover). The op timization

of source-sink relationsh ips is also

being examined with a view toobtaining a better balance of grain-

filling characters. The h exaploid

wh eat and other gene pools are

being searched for examp les of

extreme expression of these

characters. We believe advances of

yield potential on th e order of at least

20% in optimu m conditions can still

be realized by fine-tun ing the source-sink relationships in w heat.

Phenological Trait sBy m anipulating p hotoperiod and

vernalization genes, we are

attemp ting to tailor genotyp es to

specific environments. Photoperiod

and vernalization genes optimize the

timing and d uration of flowering andgrain-filling, thereby influen cing th e

wh eat plants eventua l yield. New

and d ifferent sources of these genes

are being exploited throu gh the use of

high-latitud e germplasm from Central

Asia and Canada.

Physiological Traits

A strong bod y of eviden ce nowindicates that p hysiological traits may

complement early-generation

ph enotyp ic selection in w heat. Genetic

progress in increasing yield potential

is closely associated with increased

ph otosyn thetic activity (Rees et al.

1993). Photosynthetic activity as well

as yield potential have increased over

the p ast 30 years by som e 25%. These

find ings may have m ajor imp lications

for CIMMYTs future selection

strategy, since there is evidence that

wheat genotypes with h igher

ph otosynthesis rates have lower

canopy temp eratures, a characteristic

that can be measured easily, quickly,

and cheap ly. Canopy temperatu re

depression (CTD) is the cooling effect

exhibited by a leaf as transp irationoccurs. Canopy temperatu re

dep ression and stom atal condu ctance,

measured on sunny d ays during grain

filling, have show n a strong


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9

Protecting

Yield Potential:

The Role of

Resistance to

Pathogens and Pests

Over the p ast few d ecades, the gains

from breeding for disease resistance

are likely to have been at least asimpor tant as the gains from breeding

for increased yield potential (Byerlee

and Moya 1993). A recent su rvey of

wh eat breeders in developing

countries ind icated tha t among the

types of m aterials used in crossing

(includ ing the breeder s own ad vanced

lines, advan ced lines obtained from

other countries, wild relatives, and

land races), ma terials from CIMMYT

international nurseries are the most

frequently crossed in p ur suit of disease

resistance goals (Rejesus, van Ginkel,

and Smale 1996).

CIMMYTs global effort to breed

wh eats with diverse and du rable

resistance will protect global food

secur ity by redu cing th e incidence ofd isease epidemics. It will also protect

the environment and farmers incomes,

by redu cing d epend ence on pesticides

for disease and pest control. In

CIMMYTs target m ega-environments,

impor tant fungal d iseases of wh eat

caused by obligate pa rasites includ e

the ru sts (one or m ore of which are the

most economically impor tant d iseases

in most wh eat produ ction

environmen ts), pow dery m ildew, and

the bun ts and smu ts. Widespread

diseases caused by facultative fungal

parasites include septoria tritici blotch,

septoria nodorum blotch, spot blotch,

tan sp ot, head scab, and a suite of root

rots.The obligate parasites are highly

specialized, and significant variation

exists in the p athogen p opu lation for

viru lence to specific resistance genes.

The evolu tion of new virulence (races)

through migration, mu tation, and

recombination of existing viru lences

and their selection is m ore frequent in

rust and pow dery m ildew fun gi. Forthis reason, these diseases have

required constant vigilance and

attention from breeders. Physiological

races are also know n to occur for m ost

bunts and smuts, although evolution

and selection of new races is less

frequen t. Because m ost bunts an d

smuts are easily controlled by chemical

seed treatment, little effort is current ly

placed on breeding for resistance,

except for resistance to Karnal bun t.

Successful changes in pathogen races

are even less frequent in the facultative

parasites m entioned earlier.

Since wheat cultivars d erived from

CIMMYT germplasm are grow n over a

large area and are exposed to a variety

of pathogens und er cond itions thatmay favor disease developm ent, our

strategy has been to utilize resistance

sources that are as d iverse as possible

and have show n d urability. Genetic

diversity and durability of resistance

against diseases caused by path ogens

such as the ru st path ogens are vital for

long-term food security. Resistances

caused by race-specific genes become

ineffective in a shor t time (in five years

on average at th e global level and in

three years for leaf ru st, Puccinia

recondita, in Mexico). In contrast,


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10

cultivars w ith du rable resistance have

show n stable resistance for over 50

years at the global level. Consid er the

resistance to stem ru st (P. graminis).

McFadden in the US transferred theSr2 gene comp lex from a tetrap loid

emmer w heat to hexaploid bread

wheat in th e 1920s (McFad den 1930).

Borlaug in Mexico used this source of

resistance in h is breed ing p rogram in

the 1940s, and since then this gene, in

concert with several know n and

un known major and minor genes, has

formed the basis of durable resistance

to stem ru st in CIMMYT wheat

germplasm.

Following the lesson learnt from

stem ru st research, CIMMYTs w heat

breeding in the last three decades has

focused on u tilizing d iverse sources of

slow ru sting resistance to P. recondita

and yellow rust (P. striiformis). Genetic

analyses of d urable resistance indicate

that effective d isease control can be

achieved by combining from three to

five minor, slow ru sting genes in a

single cultivar. Such resistance is

expected to provide sufficient

protection to farm ers crop against all

biotypes over a long p eriod. Currently

we are also attempting to identify

molecular markers for each of the slow

rusting genes p resent in CIMMYTwheats. If this strategy is successful,

breeding p rograms w ill be able to

incorporate known combinations of

minor genes, develop a global strategy

for their deployment, and at the same

time enh ance genetic diversity in

farmers fields.

Recent an alysis of trials conducted

in north western Mexico confirms that

progress in p rotecting yield potential

through genetic resistance to leaf rust

is about th ree times as great asad vances in yield potential itself (R.P.

Singh and K.D. Sayre, pers. comm.).

The economic benefits of CIMMYTs

strategy of incorporating non-specific,

du rable resistance to leaf rust into

mod ern bread wh eats have been

estimated using d ata on resistance

genes identified in cultivars, trial data,

and area sown to cultivars in

northwestern Mexico. Even u nd er the

most conservative scenario, the gross

benefits generated in this region on

abou t 120,000 ha of w heat from 1970 to

1990 were US$ 17 million (in 1994 real

term s) (Smale et al. 1998). At th e globa l

level, wh ere a considerable area is

sown to cultivars carrying non-specific

resistance, the benefits mu st be

correspond ingly large.

Resistance to the d iseases caused

by facultative parasites, such as

Septoria tritici and Fusarium

graminearum, also involves genes th at

have additive effects. Tremendous

progress has been m ade at CIMMYT in

developing semidw arf wheats that

have ad equate resistance to Septoria

tritici. Sources contr ibut ing toresistance includ e w heats from France,

Brazil, China, and Russia. More

recently w e have identified synthetic

wheats (T. turgidum x T. tauschii)

possessing good resistance to septoria

tritici blotch. This new genetic

diversity is currently being transferred

to CIMMYT wheats.


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13

CIMMYT germ plasm in those

environments sup ports the mod el of

combining inpu t efficiency and inpu t

responsiveness.

Another piece of eviden ce is

Nesser, an advanced line with

superior performance in drou ght

conditions. Nesser was bred at

CIMMYT-Mexico and iden tified by

the CIMMYT Mediterranean program

located at the International Center for

Agricultu ral Research in th e Dry

Areas (ICARDA) in Syria. The cross

combines the high yielding CIMMYT

variety Jup ateco 75 and th e drou ght

tolerant Australian variety W3918A.

The performance of Nesser in the

dryland en vironments of WANA has

been widely pu blicized (ICARDA

1993), and the line is considered to

represent a un iquely drough t-tolerant

genotyp e. This line was selected a t

CIMMYT/ Mexico und er favorableconditions, and it carries a

combination of inpu t efficiency and

high yield respon siveness. In th e

absence of rust, its performance is

qu ite similar to th at of Veery S.

A breeding scheme to achieve the

combination of yield responsiveness

and drou ght tolerance in w heat is

presented in Table 5. This method is

supp orted by research on wh eat aswell as other crops, in w hich testing

and selecting in a range of

environments, includ ing well-irrigated

ones, has identified superior

genotypes for stressed conditions (see,

for example, Ehdaie, Waines, and Hall

1988; Duvick 1990, 1992; Bramel-Cox

et al. 1991; Ud din, Carver, and Clutter

1992; Zavala-Garcia et al. 1992; andCoop er, Byth , and Wood ru ff 1994). The

app roach results in the selection of

germplasm that is adopted by farmers

because it tran slates imp roved

environmental conditions into yield

gains. The trad itional methodology of

selecting on ly und er d rought

conditions and narrow ly relying on

land race genotypes does not m ove

yield levels significantly beyond th ose

usu ally obtained, and it does not

provid e the farmer with a bonus in

years w hen rainfall is higher.

Table 4. Grain yields (kg/ha) of selected w heat genotypes grouped by adaptation and

tested under mois ture regimes in the Yaqui Valley, Mexico, 1989/90 and 1990/91

Full Late Early Residual

Adaptation group irrigationa droughtb droughtc moistured

ME1 (Irrigated environment) 6,636 a 4,198 a 4,576 a 3,032 a

ME4A (Mediterranean Region) 6,342 b 3,990 ab 4,390 b 3,032 a

ME4B (Southern Cone, S. America) 5,028 c 3,148 bc 4,224 b 2,359 c

ME4C (South Asian Subcontinent) 4,778 c 3,245 bc 3,657 c 2,704 b

Source: Calhoun et al. (1994).

Note: Means in the same column followed by the same letter are not significantly

different at P=0.05.

a Received 5 ir rigations.

b Received 2 irrigations early, before heading.

c Received 1 irrigation for germination and 2 post-heading.d Received 1 irrigation for germination only.


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15

is an increase of more than 20% over

the previous generation of du rum

wh eats. Generally average yields of

duru m w heat in farmers fields in

northwestern Mexico are 6 t/ ha, andthe w orld average is 2-3 t/ ha. If these

recently tested w heats retain some of

their yield advantage in marginal

conditions, they may p rove to be a

valuable asset for breeding p rograms.

Regional Researchon Wheat for Marginal

EnvironmentsWest Asia and North Africa. About

one-third of the area planted to w heat

in the d eveloping world is located in

marginal environments plagued by

drough t and soil problems. These

problems are frequently exacerbated

by a lack of infrastructure and farmer

sup port services. Most of the w orlds

drou ght-prone w heat area is

concentrated in the WANA region

(Table 1). Wheat is the principal food

source for p eople in WANA, wh o on

average consum e more than 145 kg/

cap/ yr, one of the highest levels of per

capita consumption in the world .

CIMMYT efforts aimed at

improving wheat p roduction in

WAN A are conducted in conjun ction

with ICARDA. The CIMMYT/

ICARDA Joint Drylan d Wh eat

Program for West Asia and North

Africa seeks to increase wh eat

productivity by developing spring

bread and du rum wheats that are

better adap ted to the WANA region.

Wheats developed or identified by the

program are widely adap ted and

possess enhanced d isease and insect

resistance, as w ell as better tolerance to

the p revalent abiotic stresses. This is

wh y our p artners in the region

increasingly select them for use in their

own breeding programs. Farmer

adoption of CIMMYT- and CIMMYT/

ICARDA-der ived varieties in WANA

continu es to increase, with more than

90 wheat varieties released in 21countries in the region over th e past 10

years.

The Turkey/ CIMMYT/ ICARDA

International Winter Wheat

Improvem ent Program (IWWIP) based

in Ankara, Turkey, came into existence

11 years ago with the pu rpose of

generating winter w heats for

developing countries, particularly inthe WANA region. Over the past two

years, IWWIP has expand ed its

collaboration w ith winter w heat

programs in the developing w orld.

New research partnerships w ith

colleagues from Central Asia an d the

Caucasus hav e greatly increased th e

nu mber of cooperators.

The program is devoting particularattention to imp roving resistance to

yellow rust, wh ich is the m ost serious

winter w heat d isease in WANA. It

conducts trials using ar tificial

inoculation in An kara, Konya, and

Eskisehir (Turkey), Alepp o (Syria), and

Iran. It is also conducting research on

micronutrients aimed at identifying

zinc-efficient w heats to be used incrosses and alien m aterials that m ay be

poten tial sou rces of zinc efficiency. At

present, rye and triticale seem to be th e

best sources, bu t other a lien sp ecies are

also being tested at Turkeys ukurova

University.

Central Asia and the Caucasus. The

repu blics of Central Asia an d the

Caucasus are relatively diverse inclimate, agricultu ral p rodu ction, and

pop ulation. What these eight coun tries

(Armenia, Azerba ijan , Georgia,

Kazakhstan, Kyrgyzstan , Tad jikistan,

Turkmen istan, and Uzbekistan) have in


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17

1988; Ciaffi et al. 1992; Lafiandra,

Ciaffi, and Benedetelli 1993; William ,

Pea, and Mu jeeb-Kazi et al. 1993).

These alien gen es offer a poten tial

means of expanding the n um ber ofallelic var iants controlling proteins

with desirable quality effects in wh eat.

Several of the synthetic hexap loids

developed from accessions of d iploid

Triticeae sp ecies (T. tauschii, T.

boeoticum, T. monococcum, and T. urartu)

and d uru m w heat have been examined

in relation to grain cha racteristics

associated with end -use quality of

bread and du rum wh eats. The analyses

revealed that T. tauschii may be used

for substantially increasing the n um ber

of high molecular w eight glutenin

(HMWG) subu nits present in bread

wh eat (HMWG subun it comp osition is

implicated in the definition of gluten

strength in both bread w heat and

duru m wh eat) (Payne et al. 1981;

Pogn a et al. 1990).

We have also examined var iability

for quality (grain hard ness, protein

content, and SDS-sedimentation) as

well as the relationship betw een

quality and HMWG and low molecular

weight glu tenin (LMWG) subu nit

comp osition (SDS-PAGE) in 137

accessions ofT. dicoccon. Resu lts

confirm p revious find ings that T.dicoccon has m ore diverse genetic

var iability for alleles involved in the

synthesis of gluten-type proteins than

cultivated wheat. T. dicoccon should be

considered a good poten tial source for

improv ing gluten strength in bread

and du rum wheat.

In the past three years, the

frequency of high qu ality CIMMYT

bread w heats has increased

dram atically. A mod ification of the

crossing strategy, emphasizing high

quality parents, was imp lemented in

the ear ly 1990s. Quality testing of

advanced generation breeding

materials was increased over th e past

few years. Now th ese two strategies

have come to fru ition. In the nearfutu re, abou t 75% of CIMMYTs new

bread wheat germp lasm will be

competitive for quality standards in

the marketplace.

Biotechnology

and Wheat

Improvement: An

Example of

Collaboration

By d rawing on the p ower of

biotechnology, CIMMYT seeks to make

plant breeding more efficient an d, in

some cases, to improve wheat in ways

that have elud ed conventional

breeding ap proaches. The comparative

genetic map ping of cereal genomes has

identified a vast am oun t of conserved

linearity of gene ord er (Devos and

Gale 1997). This observation is likely toaccelerate the application of

quantitative trait loci (QTL) in w heat ,

as well as aid in the identification of

genes requ ired for introgression from

alien species. Given th e low num ber of

loci tagged at p resent in wh eat, the

problems related to d eveloping a h igh-

density map for w heat (Snap e 1998),

and the limited p rogress to identifyQTL for yield in wheat , we believe that

the imp act from th is linearity on wh eat

improvement will be significant.


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20

chopp ed an d left on the su rface of the

beds. The system h as several

advan tages for farmers and the

environment, includ ing:

Nitrogen can be app lied w hen andwh ere the wheat p lants can u se it

most efficiently. Yields im prove, and

nitrogen losses into the environment

are significantly redu ced.

Water conservation improves. Aswater for agriculture becomes more

scarce in the years to come, water

conservation p ractices w ill become

more important for farmers.

Researchers in South Asia and China

report a 30% savings in water u se

from u sing bed p lanting and

improved w eed control.

Weeds can be controlled bycultivating between the beds

redu cing costs and the need for

herbicide.

Residu es are returned to the soil

withou t burning, wh ich is beneficialto the environment.

The beds can be u sed cycle aftercycle. Farm ers avoid the financial and

environm ental costs of making

repeated p asses w ith a conventional

plow du ring land p reparation.

Prototype m achinery for this bed

planting system has been d esigned

and tested in Mexico and in Asia. The

prototyp es are mod ifications of

standard agricultural equipment an d

are expected to be affordable for poor

farmers. Mexican farmers reportedly

save 30% on their prod uction costs

wh en they use the bed p lanting

system. Some 10,000 farmers are

thou ght to u se the system in Mexico,

and the num ber of farmers who areusing bed planting is growing in South

Asia and China as well. In fact, in

par ts of China some farmers find the

technology so valuable that in the

absence of equ ipment they form the

beds by hand.

Farmer Part icipatoryResearchOver th e past few years, CIMMYT has

significantly increased its investment

in farmer par ticipatory research for

natu ral resource man agement (that is,

in the development of prod uctivity-

enhancing, resource-conserving

practices for maize and wh eat systems,

with beneficial impacts on soils, water,and agroecosystem d iversity). Farmer

participa tory research is a tool for a

pu rpose: the development of

sustainable practices that imp rove

resource quality w hile raising system

productivity. CIMMYT is moving

aggressively to mainstream the use of

this tool for these imp ortant en ds. For

example, in irrigated a reas in n orthern

Mexico, CIMMYT has long

collaborated w ith farmers in the

developm ent of the bed p lanting

systems described ear lier.

In Asia, CIMMYT works with th e

other m embers of the Rice-Wheat

Consortium for the Ind o-Gangetic

Plains to foster farmer experimentation

on reduced and zero tillage strategies

for establishing w heat after rice.

Farmer group s have assessed

alternative tillage and sowing

implements and wh eat establishment

strategies, and they have been

encouraged to develop their own

innovations and adap tations.

Minimum tillage practices are

spread ing in Bangladesh, and farmers

in the western pa rt of the Indo-Gangetic Plains are beginning to use

zero tillage. Farm ers report ear lier

sowing, higher yields w ith lower levels

of inp uts, and improved possibilities


27/35

21

for diversifying cropping patterns

away from a continu ous rice-wheat

rotationwith num erous

agroecological benefits.

In Bolivia, we are collaboratingwith farmer groups to d evelop zero

tillage/ mu lch systems suitable for

smallholders (2-5 ha) in the high inter-

And ean valleys. These farmers

prod uce one crop of wh eat each year

in monoculture or in rotation w ith

potatoes, faba beans, peas, and / or

barley. Research focuses on evaluation

of straw cover to increase rainfall useefficiency. Results are extremely

encouraging: crop residu e retention

generally increases yields and redu ces

risk, two imp ortan t objectives for

Bolivias small-scale, subsisten ce

farmers. Researchers also participate

in a p roject to d evelop a small,

animal-drawn, no-till seed drill for

sowing cereals into surface residues,

and results are very positive

(CIMMYT 1999).

Information

M anagement Tools

for Sustainable

Systems

Researchers have always believed in

the value of sharing information m ore

widely, bu t the limitations of

information technology have not

made th is easy. CIMMYT now offers awid ening array of information

man agement tools to researchers in

man y d isciplines.

For examp le, the International

Wheat Information System (IWIS) is a

relational database available on CD

wh ich gives each genotyp e a unique

identifier and prov ides extensiveped igree and performan ce data. The

Genetic Resources Inform ation

Package (GRIP), designed in

conjun ction w ith Australian p artners,

allows IWIS users to locate seed

samp les in wheat germplasm stocks

in a nu mber of collections around the

world an d provides an abbreviated

version of the IWIS pedigrees. The

International Crop Information

System (ICIS) is a da ta management

tool that builds on IWIS. It contains

information on several crops in

ad dition to w heat . The core of ICIS is

a relational database structure that

stores data on plant genetic resources,

ped igrees, field and laboratory

evaluations (includ ing m olecular

information), and au xiliary d ata onlocations, institutions, and peop le.

Simple geograp hic information

functions are being incorporated into

ICIS, and a tool for expor ting d ata to

crop simu lation m odels is also und er

development.

One challenge to sharing

information more w idely is to

provid e access to cutting-edgegeographic information system (GIS)

tools for n on-GIS users, especially

those in Africa. African researchers

need spatially referenced d ata on

climate, soils, infrastructure, crop

distribution, and the natu ral resource

base, in par t to ascertain the extent to

wh ich th eir site-specific research may

have relevance to larger areas. TheAfrica Coun try Alman acs contain

such base data, along w ith the most

common ly requested map s, plus

search an d viewing tools, on a single


28/35

22

compact d isc. Almanacs have been

developed for 12 African countr ies,5

some of which have requested follow-

on d emonstrations and training for

their research staff. Now all researcherscan have access to these powerful GIS

tools, not just a few sp ecialists in a

central office.

The Spatial Characterization Tool

(SCT) developed by CIMMYT and

Texas A & M Un iversity goes a long

way towards ad dressing the p roblem

of site specificity in n atu ral resources

management research. Site researcherscan now quickly perform site

similarity analysis, identifying areas

with environm ents resembling that of

their site. When applied to sites in

Bolivia, this an alysis un covered

environmentally similar areas within

Bolivia; in n eighbor ing coun tries (e.g.,

Chile, Brazil); with in the Am ericas

(e.g., Mexico); and even in oth er

regions of the wor ld (Ethiopia,

Lesotho). Scientists in these d iverse

locations find th at they hav e mu ch to

share about technology performance

and the consequences of techn ical

change for system p rodu ctivity and

sustainability.

These information management

tools help encourage researchintegration, explore the p rospective

performan ce of new technologies, and

overcome site specificity. However, like

all information m anagem ent tools, they

need data. A final challenge is how to

preserve, organize, and make available

to researchers the rich ar ray of da ta

often gen erated by research,

par ticularly in natu ral resource

managemen t research. CIMMYT is

developing an answ er to this set of

challenges: the Sustainable Farm ing

Systems Database (SFSD). Non-

governm ental organizations are using

the SFSD prototyp e to organizeinformation on the global experience

with green m anu re cover crops. As the

SFSD matu res, its u ses will be

virtu ally infinite.

Conclusions

The strategies we h ave just outlined

could m ake the d ifference between a

sustainable futu re, with food an d

economic opp ortun ity available for

the majority, and a future of scarcity,

with su rvival seriously comprom ised

for most people. Successful,

sustainable agricultu re can help create

the pu rchasing p ower and

emp loyment that w ill ensure food

secur ity and help erad icate poverty.

We believe that the risks of ignoring

agricultu ral developm ent w ill be far

higher than the risks of deciding to

create a su stainable futu re for us a ll.

The world has faced a similar

choice before, when a decision was

mad e to sow the new semidwarf

wheats in India in the hope that their

higher yields w ould p revent a famine

as great as the d evastating Bengal

famine of 1943. That d ecision

transformed agriculture and the way

that agricultural research w as

conducted. Today CIMMYT and its

pa rtners join forces in one of the

world s most ambitious endeavors:we p articipate in a global wh eat

improvem ent system that continues to

better th e lives of millions of poor5 Including three important wheatprod ucing nations: Ethiopia, Kenya,

and Zimbabwe.


29/35

23

farmers and consum ers in

developing countries. The imp act of

that system is well documented

(Byerlee an d Moya 1993; Maredia

and Byer lee 1999; CIMMYT 1999). Inthe most recent p eriod, 1991-97,

almost 90% of the spring bread

wh eat varieties released by n ational

agricultu ral research systems had

CIMMYT ancestry (Figure 3).

Virtu ally all (98%) of the spring

du rum wh eats released by national

programs in 1991-97 had CIMMYT

ancestry (Figure 4). Farmers now

plant almost 80% of the developing

world s spring bread w heat area to

CIMMYT-related wheats (Figure 5).

CIMMYT crosses

(some re-selected by

NARSs), 56%

Figure 3. Ancestry of spring bread w heat

varieties released by national programs,

1991-97.

Source: CIMMYT wheat imp acts database.

NARS crosses with at

least one CIMMYT

parent, 28%

NARS crosses

with some

known

CIMMYT

ancestry, 5%

NARS

semidwarfs

with other

ancestry, 8%

Tall

varieties, 3%

CIMMYT

crosses, 77%

Figure 4. Ancestry of spring

durum wheat varieties

released by national

programs, 1991-97.

Source: CIMMYT wheat

impacts database.

NARS crosses w ith

at least one CIMMYT

parent, 19% NARS crosses

with some

known

CIMMYT

ancestry, 5%

Tall

varieties , 2%

100

80

60

40

20

0

ChinaIndia

OtherAsia

WANA

AllAsia

Sub-SaharanAfrica

LatinAmerica

Developingcountries

Figure 5. Area planted to spring bread

wheat in developing countries, 1997.

Source: CIMMYT wh eat impacts

database.

Percentage of total spring

bread wheat area

Unknown

Landraces

Tall wi th pedig ree

Other semidw arf

Any CIMMYTancestor

At least oneCIMMYT parent

CIMMYTcross


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24

A New Research Paradigmfor New Research ImpactsThese research impacts are reassuring,

but m uch remains to be done. When

our colleague N orman Borlaugaccepted the N obel Peace Prize for his

achievements in bringing abou t the

Green Revolution in w heat, he

cautioned th at the Green Revolution

has not transformed the world into

Utopia. None are more keenly aware of

its limitations than those wh o started it

and fough t for its success. . . . Above

all, I cannot emph asize too strongly the

fact that further p rogress depend s on

intelligent, integrated, and persistent

effort (CIMMYT 1970).

Borlaugs observation remains true.

If we are to m ake progress toward

sustainable food security, we m ust take

his advice and change the w ay we

plan, cond uct, and comm un icate about

research. We must b lend veryspecialized research d isciplines in

teams of scientists seeking ap prop riate

outcomes that have an immediate

imp act in farm ers fields. It is from

these fields that food sup plies mu st

come for the foreseeable futu re. The

farmer is the ultimate systems-oriented

operator, juggling biological, economic,

environm enta l, and social factors. In

such circumstances, isolated

interventions are of limited value at

best; all too often, they m ake th ings

worse.

These interventions will be based

on a new, integra tive research

parad igm that focuses on the elements

of the GXEXMXP equation mentioned

earlier: the best genotypes (G), in th e

right environm ents (E), un der

app ropriate crop man agement (M),

generating app ropriate outcomes for

people (P). Everyone who seeks to

foster sustainable agriculture in

developing coun tries shou ld recognize

the interdep end ence of these factors,

because m ost organizations by

themselves cannot contribute fully toeach asp ect of GXEXMXP. Partnerships

and consortia that assemble the best

possible teams to execute the GXEXMXP

app roach w ill und erpin the timely and

successful achievement of sustainable

farming systems and future food

security.

The Shape of Thingsto ComeGiven th ese requ irements, wh at w ill

agricultu ral research look like in the

new millenium ? Every member of the

international wheat improvement

systemand the farmers and

consumers w ho depend on itwill be

affected by changes in international

research in the year s to come. Which

forces are likely to shape the w ay tha t

research is doneeither by

contributing to or d etracting from the

integrative research parad igm we have

just described?

For decades, collaboration h as been

the mainsp ring of the international

wheat imp rovement system. None of

the achievements described in this

pap er could have been attained

withou t it. Gains from conventional

breeding will continu e to be significant

in the next two d ecades or more

(Duvick 1996), but these are likely to

come at a higher cost than in the past.

Research m anagers and p olicy makers

are increasingly concerned that the

very op en, collaborative netw orks that

have sustained the wh eat imp rovementsystem w ill become far m ore

circum scribed in coming years.


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27

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