Acevedo, E. (1991) Morphophysiological traits of adaptation of cereals to Mediterranean environments. In E. Acevedo, E. Fereres, C. Giménez & J.P. Srivastava, eds. Improvement and Management of Winter Cereals under Temperature, Drought and Salinity Stress. Proc. ICARDA-INIA Symp., Cordoba, Spain, 26-29 Oct. 1987, p. 85-96.Calderini D.F., Reynolds M.P., Slafer G.A. (2006) Source-sink effects on grain weight of bread wheat, durum wheat, and triticale at different locations. Australian Journal of Agricultural Research, 57, 227-233.Fischer R.A., Maurer R. (1978)Drought resistance in spring wheat cultivars. I Grain yield responses. Australian Journal of Agricultural Research, 29, 897-912.Josephides C.M. (1993)Analysis of adaptation of barley, triticale, durum and bread wheat under Mediterranean conditions. Euphytica, 65, 1-8.López-Castañeda C., Richards R.A. (1994)Variation in temperate cereals in rainfed environments I. Grain yield, biomass and agronomic characteristics. Field Crops Research, 37, 51-62.Palumbo M., Boggini G., (1994)Comparison of durum wheat, bread wheat and barley in a Mediterranean environment. Cereal Research Communications, 22, 113-120.Zubaidi A., McDonald G. K., Hollamby G. J., (1999)Shoot growth, root growth and grain yield of bread and durum wheat in south Australia. Australian Journal of Experimental Agriculture, 39, 709-720.

Jordi Marti 1, Gustavo A. Slafer1,2

1Department of Crop and Forest Sciences and AGROTECNIO (Centre for Research in Agrotechnology), University of Lleida, Av. Rovira Roure 191, 25198, Lleida, Spain2ICREA, (Catalonian Institution for Research and Advanced Studies) jordi.marsal@pvcf.udl.es

• Three field experiments (2004-05, exp. I; 2005-06, exp. II; 2006-07, exp. III) in the Mediterranean location of Agramunt (Catalonia, NE Spain). In farmers fields

• We compared the performance of both durum(cvs. Simeto, Claudio and Vitron) and bread wheat (Anza, Soissonand Provinciale)

• Under a combination of water x nitrogen treatments en each season. (the range of yields was from less than 1 to more than 8 Mg ha-1)

• Sowing date and density were optimal

• We determined yield components at maturity and biomass at flowering and maturity. We also measured canopy reflectance and calculated NDVI

Therefore, there was no relationship between the differences in yield between these wheats and their differences in biomass at anthesis

0.0 1.5 3.0 4.5 6.0 7.5 9.00.0

1.5

3.0

4.5

6.0

7.5

9.0

Durum Yield (Mg ha-1)

Bre

ad Y

ield

(M

g h

a-1)

The average NDVI after anthesis(as well as the area under the curve of NDVI vs post-anthesistime; not shown here) showed a similar pattern to those of post-anthesis growth and yield

Y=(0.82 ± 0.03)x + 0.88 ± 0.17

0 100 200 3000

100

200

300

Spike weight at anthesis DW (g m -2)

Sp

ike

wei

gh

t at

an

thes

is B

W (

g m

-2)

Y=(0.73 ± 0.05)x + 33.99 ± 9.04

0.0 0.2 0.4 0.60.0

0.2

0.4

0.6

NDVI average post-anthesis DW

ND

VI a

vera

ge

po

st-a

nth

esis

BW

0.6 0.9 1.2 1.50.0

0.4

0.8

1.2

1.6

DW/BW NDVI average post-anthesis

DW

/BW

po

st-a

nth

esis

bio

mas

s

Y=(0.68 ± 0.04)x + 0.99 ± 0.16

Y=(0.89± 0.04)x +0.02± 0.01

Y= 0.50x + 0.46R2 = 0.74

Y= 2.69x – 1.82R2 = 0.50

We tested the hypothesis that durum wheat is more adapted than bread to relatively lower-yielding environments and that bread wheat has a superior yielding potential than durum wheat and analysed possible causes; with 3 years of field experiments under a wide range of water and nitrogen treatments.

• Durum wheat is most commonly grown in locations with lower precipitations than those in which bread wheat is grown (Acevedo, 1991).

• This implies a belief that bread wheat would be higher-yielding in relatively good environments, whilst durum wheat would be better adapted to relatively lower-yielding conditions (López-Castañeda and Richards, 1994).

• Unfortunately, there have been only few studies in which the performance of both bread and durum wheat were directly compared (Fischer and Mauer, 1978; Josephides, 1993; Palumbo and Boggini, 1994; Zubaidiet al., 1999; Calderini et al., 2006), and their results are not conclusive.

Comparison established over a wide range of conditions which produced a large range of biomass (c. 2.3-19.6 Mg ha-1) and yield (c. 0.6-8.7 Mg ha-1)

Although averaged yield was similar for both wheats (c. 4 Mg ha-1), bread wheat outyielded durum wheat in severely stressed environments while durum wheat possessed a higher yield potential

Spike dry weight at anthesis responded similarly to yield and presumably generated differences in sink strength, which might affect the capacity of canopy to grow after anthesis (both wheats grew similarly before anthesis but after anthesisbread wheat grew more than durum wheat in relatively poor environments and vice-versa

0 3 6 90

3

6

9

Y=(1.07 ± 0.03)x - 0.28 ± 0.28

0 4 8 12 160

4

8

12

16

DW biomass at anthesis (Mg ha -1)

BW

bio

mas

sat

an

thes

is(M

gh

a-1

)

BW

po

st-a

nth

esis

gro

wth

(Mg

ha

-1)

DW post-anthesis growth (Mg ha-1)

0.0 0.4 0.8 1.2 1.60.0

0.4

0.8

1.2

1.6

DW/BW biomass at anthesis

DW

/BW

yie

ld

0.0 0.5 1.0 1.5 2.00.0

0.4

0.8

1.2

1.6

DW/BW post-anthesis biomass

DW

/BW

yie

ld

In contrast their differences in post-anthesis growth explained a large proportion of their differences in yield.

Consequently the ratio between both wheats in NDVI after anthesisexplained a significant proportion of the variation in the ratio of post-anthesis growth

Experimental field in Agramunt, Lleida-Spain.