Integrating Empirical and Analytical Approaches to Investigate Genotype × Environment Interactions in Sugarcane

Abstract

ABSTRACTThe causes of genotype × environment (G × E) interactions in sugarcane (Saccharum spp.) are unclear. The objectives of this study were to (i) investigate the G × E interactions and site similarity in two selection programs in South Africa, (ii) identify factors responsible for G × E interactions, and (iii) illustrate the integrated use of crop models and climatic data to better understand G × E interactions. Data from eight series of trials were analyzed using variance components, genotype plus genotype × environment (GGE) biplots, and additive main effects and multiplicative interaction (AMMI). Crop model simulations helped summarize environmental covariates before and after canopy closure. Environmental covariates and genotypic traits were correlated to AMMI scores and superimposed on biplots. The G × E interaction accounted for more variation than the main effect of genotype and the repeatable component of G × E was dominant across all series. Two sites were identified as redundant and were recommended for removal. Sites from one program were characterized by higher rainfall and lower water stress compared with sites from the other. The enriched AMMI2 biplots allowed for identification of factors that influenced genotypic traits and permitted biological interpretations and trait relations to be studied. This study has illustrated new approaches to integrate G × E studies with environmental data for comprehensive sugarcane G × E interpretations.