Assessment barley genotypes using stress tolerance indices in normal and drought stress conditions

To evaluate the drought tolerance of barley, eight foreign genotypes and two Iranian cultivars were studied in two drought and irrigated conditions during 2013-14 in a RCB design with three replications. The results showed that the highest grain yield under irrigated conditions were belonged to genotypes 79 (9274.7 kg.ha-1), 95 (9421.7 kg.ha-1) & 120 (9362.3 kg.ha-1) and Yousef cultivar (9353.7 kg.ha-1) and under drought conditions belonged to genotypes 95 (8197.7 kg.ha-1) and 120 (8487.7 kg.ha-1). In both conditions, the lowest yield was found in genotype 21 (2270 kg.ha-1). There was not correlation between the results obtained by two group indices (sensitive evaluation indices vs. tolerance evaluation indices) in identification of tolerant genotypes, so that based on TOL, LOS and SSI genotypes 21, 97 & 125 and Reyhan cultivar were sensitive and low yielding genotypes, while based on MP, STI, GMP and HAR, genotypes 95 & 120 and Yousef cultivar had highest drought tolerance. To selection and introduce the best criteria of drought tolerance, the correlation of above indices with yield under normal and drought stress was evaluated. According to the results of the correlation between stress indices MP, GMP, HMP, YI and STI had significant correlation with yield under both normal and stress conditions, which indicating that using these criteria for evaluation of drought tolerance will be more desirable in breeding programs. According to these indices and high yield of genotypes under both environmental conditions, genotypes 95 and 120 were found to be the best genotypes.