Evaluation of Drought Stress Tolerance in Barley Lines Using Tolerance Indices

Drought stress is one of the most important environmental factors in reducing barley grain yield and despite recent advances in breeding this crop, there is still a need to improve drought tolerant barley cultivars in the country. In the present study, 81 barley lines were studied during the cropping years of 2018-2019 and 2019-2020 in both normal irrigation and drought stress conditions in the tillering stage. Drought stress was applied using evaporation pan in terms of 50 mm evaporation from the pan. Evaluation of drought stress tolerance using different stress tolerance indices while confirming the existence of genetic diversity, showed that lines No. 38, 48 and 67 with high grain yield in both conditions have high drought tolerance. Most indices had a significant correlation with average yield but the highest correlation with yield was related to K1STI, MP and GMP indices under drought stress and YI, WGMI, K2STI and HM indices under normal irrigation conditions. By cluster analysis, the genotypes were divided into four groups. The genotypes in the first group and to some extent in the second group were acceptable in terms of performance in both environmental conditions and stress tolerance indices, while more than half of genotypes were sensitive to drought stress. Finally, the results of principal component analysis were in good agreement with the results of other methods The information of the present study can be used in performance comparison experiments and other future breeding programs.