Multi-environment evaluation of winter bread wheat genotypes under rainfed conditions of Iran-using AMMI model

Genotype × environment interaction is an important and challenging issue for plant breeders in developing new improved varieties. This study aimedto estimate the impact of genotype × environment interactions for grain yield in winter wheat under rainfed conditions using the additive main effects and multiplicative interaction (AMMI) model, and to select genotypes with high grain yield, yield stability, and adaptation for cold rainfed environments in Iran. Twenty-two breeding lines and two commercial winter wheat cultivars, representing winter wheat-growing cold rainfed areas of Iran, were tested in eight locations over three crop cycles (2011-14). Environment was the pre dominant source of variation, accounting for 84.8% of the total sum of squares, with the remainder due to the genotype × environment interaction effect (which was almost four times that of the genotype effect). Average grain yield varied from 1125 to 1608 kg ha-1 across the 24 environments, with an average of 1385 kg ha-1. The AMMI biplots identified genotypes with wide and specific adaptation as well as environments with high and low genotype discrimination and characterization. Relative humidity, freezing days, and plant height were among the environmental factors and genotypic co-variables that contributed highly to genotype × environment interactions for grain yield. These findings could identify breeding lines as potential genetic resources for improving and stabilizing grain yield in winter bread wheat breeding programs for cold rainfed areas of Iran, through exploitingand minimizing thegenotype × environment interaction.