Abstract
Yield under water stress (YS) is used as the main criterion in the selection of wheat varieties for dry Mediterranean environments. It has been proposed that selection of genotypes using YS assisted by morphological and physiological traits associated with YS is more efficient in selecting high yielding genotypes for dry environments. A study was carried out at the Antumapu Experiment Station of the University of Chile, located in Santiago, Chile (33° 40′S and 70° 38′ W). The objective was to evaluate the extent to which morpho physiological traits could explain YS. For this purpose, grain yield and yield components of 185 durum wheat genotypes from ICARDA (International Center for Agricultural Research in the Dry Areas) and INIA (Chilean National Institute for Agricultural Research) were evaluated along with seed size and weight, days to heading (DH), glaucousness (GLAU), plant height (PH) and 13C discrimination (Δ). The design was an α-lattice with two replications, the genotypes were grown in two different water conditions (high and low irrigation) during two seasons (2011-2012/2012-2013). Grain weight (GW) was the only yield component with high H associated with YS, but it was not associated with yield under high irrigation (YI). The combination of YI with DH+GLAU+PH+Δ+GW obtained in LI environments explained a greater fraction of YS (38%) across years; these traits had lower genotype x environment interaction than YS, they also explained a higher proportion of yield under drought than YI. None of the traits studied could replace YS in selections for grain yield. It is concluded that these traits could aid in the selection of durum wheat subject to water stress, particularly in early generations.
Highlights
Obtaining high yielding genotypes of Durum wheat (Triticum turgidum L. ssp. durum) for different environments, especially Mediterranean rainfed areas, is considered difficult due to high genotype x environment interaction (Annicchiarico, 2002; Acevedo and Silva, 2007)
All variables were associated with yield in at least one year under the low irrigation treatment, but not all the variables were associated with yield under high irrigation
In all environments yield components had higher association with yield than the morphological and physiological traits, except for grain weight, which associated with yield in both years under low irrigation, was not associated with yield in either year when the crop was fully irrigated. was the only physiological trait associated with yield under high irrigation
Summary
Obtaining high yielding genotypes of Durum wheat (Triticum turgidum L. ssp. durum) for different environments, especially Mediterranean rainfed areas (rainy, cold winters and dry, hot summers), is considered difficult due to high genotype x environment interaction (Annicchiarico, 2002; Acevedo and Silva, 2007). Durum) for different environments, especially Mediterranean rainfed areas (rainy, cold winters and dry, hot summers), is considered difficult due to high genotype x environment interaction (Annicchiarico, 2002; Acevedo and Silva, 2007). For this reason, several authors have proposed that genotype selection under Mediterranean rainfed conditions may be improved by selecting for traits associated with yield under water stress (YS) having higher heritability than yield (Donald, 1968; Acevedo, 1992; Quarrie et al, 1999; Reynolds, 2006; McIntyre et al, 2010). GM2 has shown similar heritability to yield in bread wheat and Durum wheat (Nachit and Ketata, 1991; Acevedo, 1992) yield improvements under water stress using GM2 have had limited success, since GM2 is as unpredictable as yield itself (Dolferus et al, 2011)
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