Genotype-by-environment interaction of grain yield among candidate dryland wheat genotypes

Genotype-by-environment interaction (GEI) analysis is an essential step to identify superior and stable yielding genotypes and suitable test environments for cultivar development. The objective of the present study was to examine GEI of grain yield among candidate dryland wheat genotypes and to identify promising genotypes for breeding. Seventeen genetically diverse wheat genotypes were evaluated at two sites during the 2015 (high-yielding environment) and 2016 (low-yielding environment) growing seasons in the Limpopo province, South Africa. Grain yield data were subjected to the additive main effect and multiplicative interaction (AMMI) and genotype and genotype-by-environment (GGE) biplot analyses. AMMI analysis of variance revealed highly significant (p <= 0.001) differences among genotypes (G), environments (E) and GEI effects, suggesting differential genotypic response across test environments. Large E (90.5%), and low G (2.96%) and GEI (4.1%) effects were observed on grain yield response. The study identified genotypes G312, G344 and G717 as high yielding and stable, and these were recommended as useful genetic resources for breeding of high-yielding genotypes under South African conditions or similar environments.