Study of relationship between morpho-physiological traits and grain yield under terminal drought stress conditions in barley genotypes

Climate change is a major threat to the growth of most crops in arid and semi-arid regions. Drought stress is one of the results of climate change that has a negative impact on the growth and yield of crops. In order to investigate the morpho-physiological traits and their relationship with grain yield in barley and to determine the best criteria for selection under terminal drought stress conditions, 20 barley genotypes (Hordeum vulgare L.) were evaluated during two cropping seasons 2016-2017 and 2017-2018 under terminal drought stress conditions (irrigation cut at 50% heading) using a randomized complete block design with three replications. During the experiment, days to heading, days to maturity, number of fertile tillers, plant height, peduncle length, peduncle weight, spike length, number of grain per spike, 1000-kernel weight, remobilization, remobilization efficiency, biological yield, harvest index and grain yield were measured. Variance analysis of the studied traits showed significant difference for most traits for genotype effects. Mean comparison showed that the highest grain yield was related to genotypes 16 and 11. Correlation, regression and path analysis showed that remobilization, harvest index, biological yield and peduncle weight had the most effects on grain yield under drought stress conditions. This indicates that these traits can be used in barley breeding for grain yield improvement under terminal drought stress conditions. Three genotypes, 4, 11 16 with the highest remobilization, harvest index, biological yield and peduncle weight achieved higher grain yields under the stress conditions.