Genotype × environment interactions for grain micronutrient contents in sorghum [Sorghum bicolor (L.) Moench]

Assessment of the stability of grain iron (Fe) and zinc (Zn) content across growing regions is a pre-requisite in breeding for micronutrient enrichment in grains. Grain Fe and Zn contents were estimated in a set of 10 sorghum genotypes grown at six locations.The Fe and Zn in grain ranged from 28.9–34.9 mg/kg and 20.4–25.7 mg/kg, respectively, across the locations. Significant genotype × environment (G × E) interactions were observed for both grain Fe and Zn, indicating differential nutrient accumulation by the genotypes. Additive main effects and multiplicative interaction (AMMI) analysis indicated that the first two principal components were significant and contributed more than 75% of G × E sum of squares. Though environment (linear) variance was significant indicating linear sensitivity, significant pooled deviation for both the traits suggested that expression in some of the genotypes fluctuated significantly from their respective linear path of response to environments. The study shows the necessity of multi-location as well as multi-season evaluation of genotypes for identifying stable donors that can be used in breeding programmes for micronutrient enrichment.