Combination of AMMI, GGE biplot, stability parameters, and physiological traits in promising barley genotypes under water-deficit condition

Successful improvement of stable genotypes is dependent on the interaction of genotype with environment, which has a great influence on breeding new barley (Hordeum vulgare) varieties. The main objectives of this study were to (1) evaluate the effectiveness of drought tolerance indices for the selection of drought-tolerant barley genotypes, (2) identify stable high-yielding genotypes in variable environments, and (3) survey physiological traits of five contrasting genotypes under water deficit. In this experiment, 18 spring barley genotypes were evaluated under two moisture regimes (normal and deficit irrigations) for 2 years during the crop periods of 2022–2023 in Varamin Agriculture Experimental Station. In order to identify drought-tolerant barley genotypes in response to water deficit, GGE (genotype and genotype by environment interaction) biplot and AMMI (additive main effects and multiplicative interaction) analysis, stability parameters, and drought indices under water deficit and normal condition were used. Also, physiological traits in three tissues (leaf, penultimate, and peduncle) were measured. Based on our results, AMMI and GGE biplot analysis revealed that the G15 genotype was superior to other genotypes under water-deficit condition. Based on the physiological traits, the G3 and G15 had higher chlorophyll content and carotenoids than other genotypes under water deficit as compared to normal condition. Our results demonstrate the efficiency of the stability evaluation techniques to select genotypes that are high-yielding and responsive to drought stress condition.