Traits Explaining Durum Wheat (Triticum turgidum L. spp. Durum) Yield in Dry Chilean Mediterranean Environments

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.

Variation and Relationships among Agronomic Traits in Durum Wheat [Triticum turgidum(L.) Thell. ssp.turgidumconv.durum(Desf.) MacKey] under South Mediterranean Growth Conditions: Stepwise and Path Analyses

“…Broad-sense heritability was low to medium, (51.02%), suggesting a sizeable environmental effect on the expression of this trait. In their studies, Graziani et al [2] and González-Ribot et al [25] found a low heritability of 27% for spike number. Similarly, grain and straw yields expressed low broad-sense heritability, high phenotypic and genotypic coefficients of variation, and significant ranges.…”

“…Based on genotypic coefficient of variation and broad-sense heritability, aboveground biomass appeared to be amenable to improvement, within the set of studied genotypes. González-Ribot et al [25] reported a very low heritability of 9% for aboveground biomass.…”

“…On the other hand, Graziani et al [2] found high broadsense heritability for yield, in contrast with González-Ribot et al [25]. For the yield components (spike number, grain number, and grain number per spike) and harvest index, broad-sense heritability was low to moderate [2,25]. Mohsin et al [26] and Arya et al [32] found high broad-sense heritability for harvest index.…”

“…It only requires one sample at maturity and a minimum process of the sample to divide the components in the sample, and by multiplying these components, one can obtain the yield [22]. Grain number and grain weight are the main components affecting grain yield and are negatively correlated [23][24][25]. Graziani et al [2] reported that, among yield components, number of grains m −2 showed the strongest correlation with grain yield.…”

Agro-Physiological Characterization of Durum Wheat Genotypes Under Drought Conditions

“…Traits associated with drought tolerance in durum wheat 485 morphological and physiological traits associated with yield under the drought stress is more efficient in selecting high yielding genotypes for dry environments (González-Ribot et al, 2017).…”