Morpho-physiological response of durum wheat genotypes to drought stress

Abstract

The impact of moisture stress on phenology and growth varies for genotypes and the growth stages at which stress is encountered. The aim of this study was to determine the effect of moisture stress on some morpho-physiological traits of durum wheat genotypes under optimum and stress moisture conditions. Genotypes differing in their responses to moisture stress were grown under differing water regimes, one at 70% and the other at 35% available soil moisture. Differences in days to heading, anthesis and physiological maturity were highly significant among genotypes at the two moisture levels. Drought stress delayed the major growth stages. Although this was not expected, it has been reported previously in durum wheat. Variability in relative growth rate, components of relative growth rate, net assimilation rate and leaf area ratio was significant. Drought tolerant genotypes had fast early growth. Variation in relative growth rate was associated with both the net assimilation rate and leaf area ratio. The variation in leaf area ratio under control conditions was both due to specific leaf area and leaf weight ratio. However, under stress conditions, ability to maintain higher leaf area ratio was mainly due to higher specific leaf area.