Responses of Ethiopian durum wheat (Triticum turgidum var durum L.) genotypes to drought stress

The aim of this study was to identify yield components associated with drought tolerance in durum wheat. Twenty six durum wheat genotypes, from different agro-ecologies of Ethiopia were evaluated under moisture stress and non-stress conditions (35% and 70% available soil moisture) in a glasshouse throughout the growing period. Stress caused an average grain yield reduction of 79.7%; and a harvest index reduction of 45.2%. Drought susceptibility index proved useful to compare genotypes under stressed conditions. Yield was significantly correlated primarily with number of kernels per spike and 100 kernel weight. Further decompositions of simple correlation coefficients into direct and indirect effects showed that number of kernels per spike and 100 kernel weight had the largest direct effects on grain yield, under both stressed and non-stressed conditions. Number of spikes per plant under the high moisture level was correlated significantly, but negatively, with grain yield because of its large indirect effect on number of kernels per spike and 100 kernel weight.