Genotype-by-environment interaction and yield stability of sunflower hybrids across production environments in South Africa

Abstract

Genotype-by-environment interaction (GEI) is typical in multi-environment trials, which complicates the identification of superior genotypes, making selection and recommendation of new sunflower genotypes for different environments challenging and expensive. The objectives of this study were to investigate the GEI, identify the most discriminating and representative environments, and determine the performance and yield stability of 15 sunflower cultivars across diverse environments in South Africa. A randomised complete block design with three replicates was used. Seed yield data were subjected to combined analysis of variance, and a genotype main effects and genotype environment interaction (GGE) bi-plot method. The results showed that environment, genotype and genotype-by-environment interaction significantly affected seed yield. The environment effect was a predominant source of variation and accounted for 52.95% of the total sum of squares, whereas genotypic and GEI effects contributed 2.73% and 20.98%, respectively. The GGE bi-plot explained 60.67% of the total variation relative to genotype, GEI and showed that G9, G14, G12, G4 and G13 were high yielding, stable and might be considered as desirable genotypes. In terms of location, Senekal (E14) was identified to be the most discriminating and representative environment to evaluate sunflower genotypes.