Genetic analysis of important agronomic traits in some of barley (Hordeumvulgare L.) cultivars under normal and drought stressconditions

In this research, the genetic analysis of some of the important agronomic traits in a number of barley cultivars was investigated under favorable irrigation (non-stress) and drought stress conditionsusing Griffing’s secondmethod and GGE-biplot. The plant materials consisted of seven barley cultivars (Valfajr, Makuei, Kavir, Reyhan, Gorgan-4, Nosrat and Nimrouz) and 21 hybrids derived from their half diallel crosses that were evaluated using a randomized complete block design with three replications under two favorable irrigation and drought stress conditions in 2015-2016. Genotypic mean squares for all studied traits except for harvest index and plant height undernormal irrigation conditions and harvest index, plant height and awn length under drought stress conditions were significant. Specific combining ability (SCA) was also significant for all traits except for stem diameter and seed length under normal conditions and biological yield, spike length, 100-grain weight and peduncle length under drought stress conditions. GGE biplot graph for grain yield explained 83.1% and 86.5% of total varianceunder favorableirrigation and drought stress conditions, respectively. Evaluating the general combining ability (GCA) of the studied lines under both favorable irrigation and drought stress conditions showed that Nusrat, Valfajr, Kavir, Nimrouz, Makuei, Reyhan and Gorgan-4 lines had the higher GCA, respectively. Assessing the SCA also showed that Nosrat, Reyhan and Gorgan-4 lines under favorable irrigation conditions and Nosrat and Valfajr lines underdrought stress conditions had the higher SCA than the other lines.Also, Valfajr × Nosrat and Kavir × Nosrat hybrids under favorable irrigation conditions and Valfajr × Nimrouz and Kavir × Nosrat hybrids under drought stress conditionswere the best hybrids in this research.