The genetics of environmental variation of dry matter grain yield in maize.

Dry matter grain yield per plot from three genetically homogeneous single-cross maize hybrids were analysed to investigate whether environmental variance depends on genotype. Three genotypes were tested at 20 locations in 3 years. The data were analysed using a non-parametric approach and fully parametric Bayesian models. Both analyses reveal effects of genotype on environmental variation. The Bayesian analyses indicate that genotype by location-year interactions are the most important effects acting at the level of the mean. The best-fitting Bayesian model is one postulating genotype by location-year interactions acting on the mean and main effects of genotype and of location-year on the variance. Despite the detection of genotypic effects acting on the variance, location-year effects constitute the biggest relative source of variance heterogeneity.