Using environmental covariates to explain genotype x environment and QTL x environment interactions for agronomic traits on chromosome 3A of wheat

Genotype x environment interactions (GEI) and quantitative trait loci x environment interactions (QEI) are known to influence the expression of agronomic performance traits in wheat. The aim of this study was to provide biological and environmental explanations for large GEI and QEI known to affect the expression of genes on chromosome 3A of wheat (Triticum aestivum L.). Agronomic performance and molecular marker data available for a population of chromosome 3A recombinant inbred chromosome lines (RICLs-3A) in seven environments was used along with environmental covariate data to construct individual factorial regressions to explain GEI and QEI. Precipitation and temperature before anthesis had the greatest influence on agronomic performance traits for the RICLs-3A, and explained a sizeable portion of the total GEI for those traits. Individual molecular marker x environmental covariate interactions explained a large portion of the total marker x environment interactions for several agronomic traits. Seventy-six percent of the QEI for a major grain yield quantitative trait locus (QTL) was explained by the effect of temperature during preanthesis growth on dissimilar QTL genotype differentials across testing environments. Environmental covariates provided a strong basis for explaining QEI using marker x environmental covariate interactions.