Analysis of genotype by environment interaction in barley across various locations in Iran using the AMMI model

Barley (Hordeum vulgare) is an important global grain valued for its versatility and adaptability. This study utilized additive main effects and multiplicative interactions (AMMI) analysis to assess the adaptability and yield stability of twenty barley genotypes across eight locations, aiming to compare genotypes and identify suitable candidates. Significant genotypic variation was found for grain yield, highlighting the potential for targeted improvement. The AMMI analysis revealed that genotype, environment (location), and genotype-environment interaction (GEI), along with the first four interaction principal component axes, accounted for 86% of the yield variation. Environmental effects contributed 75.89% of the total sum of squares, while genotypic effects accounted for only 4.46%, and GEI effects for 19.65%. Isfahan and Karaj showed the highest GE interaction, indicated by their elevated IPCA1 scores in the AMMI1 biplot, while Birjand, Neishabor, and Varamin had the lowest scores and minimal GE interaction. The biplots identified genotypes 4 and 12 as the most stable and high-yielding, making them suitable for future genetic improvement programs. Conversely, genotypes 5, 10, 14, and 17 exhibited below-average yields and high IPCA1 scores, indicating instability but adaptation to specific locations. Crossbreeding contrasting genotypes could be beneficial for developing mapping populations for stability and yield genome studies in barley.