Identifying stable and resilient advanced barley (Hordeum vulgare L.) lines analyzed using AMMI and GGE biplot models...

The primary objective of this study was to quantify genotype-by-environment interactions for grain yield, and to evaluate drought tolerance in newly developed advanced barley lines. Sixteen barley lines were evaluated over a four consecutive year (2020-2023) across five distinct agro-ecological zones in Iran under rainfed field conditions. Grain yield ranged from 0.210 t ha^-1 (2022) to 0.376 t ha^-1 (2023), with an overall mean of 1.883 t ha^-1. Analysis of variance indicated that environmental effects were the dominant source of variation, accounting for 87.47% of the total sum of squares and explaining 88.18% of the phenotypic variance ([Formula: see text]). The G×E interaction and genotypic main effects contributed 4.71% and 0.97% of the total variation, respectively. Broad-sense heritability for grain yield was estimated at 66.8%. Based on the additive main effects and multiplicative interaction (AMMI) analysis, lines G9, G8 and G15 showed the highest yield stability, but G14 showed the highest grain yield with acceptable stability across environments. The genotype plus genotype-by-environment (GGE) biplot further identified Lorestan and Ilam as distinct mega-environments, providing a clearer environmental classification than that obtained with the AMMI model. The standard check cultivar G1 (Khorram), together with lines G3, G12, G13, and G14, were identified as superior genotypes in terms of both performance and stability in the GGE biplot analysis. Lines G2 and G9 exhibited enhanced drought tolerance, particularly in the most recent growing season. In the final test environment i.e. Ilam in year 2023, complementary trails revealed that line G14 was characterized by early flowering, a high number of spikes per unit area, increased 1000-grain weight, and strong drought tolerance. Line G13 showed early maturity and pronounced tolerance to stress conditions. Considering the complementary insights provided by the AMMI and GGE biplot models, the identified superior genotypes-especially G9, G8, G14 and G13-are recommended for utilization in future barley breeding programs targeting yield stability and drought-prone environments.