Genetic diversity and screening barley genotypes which possess desired agronomic traits as well as a high level of drought tolerance amongst the F3 lines obtained by crossing a cultivated species (Reihan 03) with two wild species (HSP21 and HSP45) in 2015-16 cropping season For this purpose, 162 lines (including 81 lines from each breeding population) were evaluated through an Augmented Design experiment in three different environments including without stress as control, moderate drought stress and severe drought stress. The results showed that in both populations the highest and the least variation was obtained for the traits of number of grain per spike and number of days to physiological maturity, respectively. The highest grain yield in progeny of crossing with the wild parent, HSP21, in both without stress and moderate stress conditions was revealed by the 584 genotype, whereas the highest value in severe stress condition belonged to the 592 genotype. The highest grain yield in progeny of crossing with the wild parent, HSP45, in three mentioned environments was observed for the genotype numbers 689, 671 and 715, respectively. It was indicated by the comparison of two populations in without stress condition that the offspring obtained by crossing the cultivated species of Reihan 03 with the wild species of HSP45 showed a significant decrease in mean plant height, mean weight of 100 grains, mean grain yield and mean harvest index as compared to those obtained by crossing Reihan 03 with HSP21, whereas they showed a significantly increased number of grains per spike and number of days to physiological maturity. In stressful environment, mean of plant height and mean of weight of 100 grains in the offspring obtained by crossing Reihan 03 with HSP21 were lower than those of the population obtained by HSP45, while other traits were not significantly different between two populations. In the severe stress environment, the offspring obtained by crossing Reihan 03 with the wild species of HSP45 showed a significant increase in mean spike length, mean number of grain per spike, mean biological yield and mean grain yield as compared to those obtained by crossing Reihan 03 with HSP21, whereas they had a significantly decreased weight of 100 grains. The correlation coefficient analysis for the offspring of crossing Reihan 03 with HSP21 in moderate and severe stress environments showed that grain yield was significantly positively correlated with plant height, biological yield, stress tolerance index (STI) and yield stability index (YSI). High-yielding lines in both normal and drought stress conditions were ultimately identified by applying multivariate procedures and drought tolerance indexes for further studies in future. Keywords : drought stress, screening, augmented design, genetic variation, Hordeum spontaneum .
