Genotype x Environment Interactions for Grain Yield in Rainfed Winter Wheat Multi-Environment Trials in Iran

Abstract

Genotype x environment (G x E) interaction analysis was investigated on grain yield of 20 winter wheat genotypes grown in 24 environments in cold winter areas of Iran during 3 yr. Cluster and biplot analyses were applied to separate testing environments into groups with the same top-yielding genotypes. Environment followed by G x E interaction effects accounted for the greatest proportion of the variability of grain yield of winter wheat genotypes. Cluster analysis divided both genotypes and environments into three groups, which accounted for 64.4% of the G x E sum of squares (SS). Biplot analysis confirmed the classification analysis and showed that different environment groups tend to discriminate genotype groups in dissimilar fashions. The genotype group G-I with the highest yielding performance had the best adaptation to environment groups with the highest (E-I) and the lowest (E-III) yield potential. Genotype group G-II was adapted to environment group E-II with average yield potential, while the genotype group G-III appeared to have the poorest adaptation to environment groups. The environmental PC1 leads to noncrossover G x E interactions, while PC2 represents a disproportional genotype response across locations, explaining crossover G x E interactions. The testing environments involved in E-I and E-III with large PC1 scores and low PC2 scores were the best for genotype discrimination. Results show that the highest yielding genotypes G4, G10, and G17 with the lowest changes in grain yields across environments were the most stable and are consequently good candidates for commercial release in cold winter areas of Iran.