Abstract
THIS RESEARCH was conducted in order to identify the best barley genotypes that can be grown under drought stress conditions. This experiment was conducted in a randomized complete block design with three replications at the Agriculture Experimental Research Farm of the Faculty of Agriculture, Sohag University, during the 2006 to 2008 seasons. Twenty barley genotypes (covered, 2-rowed) and the two check cultivars Giza 127 and Giza 128 were evaluated for drought tolerance by measuring yield performance under three levels of irrigation (normal, moderately reduced and severely reduced). Drought stress reduced grain yield (ardab/fad) by reducing the number of spikes/m(2), the number of kernels/spike and 1000-kernel weight. This study showed that, the best genotypes of barley for all parameters studied under severe drought conditions were No. 17, No. 7 and No.13. The drought susceptibility index (DSI) of grain yield (ardab/fad) showed that nine genotypes had a (DSI) < 1 and were relatively tolerant to drought stress. The results revealed that the reduction in grain yield for the highest genotype, (No. 17) and the lowest one, (No. 9) due to drought increase was 22.66 and 26.28%, respectively, with a general mean of (28.82+1.35).