Genotype-environment interaction in maize hybrids: a multivariate relationship between yield components, morphological variables and disease tolerance

Abstract

ABSTRACT Knowledge of phenotypical variables, yield and susceptibility to diseases may clarify why some hybrids are more productive than others. In this study, we evaluated the stability and responsiveness of genotype-environment interactions on phenological variables, yield components and susceptibility to diseases of maize hybrids. Experiments were conducted in 5 regions in the Brazilian Midwest. Two population were used for each hybrid in each region, totalling 10 systems-environments. Data were analysed by Restricted Maximum Likelihood; Best Unbiased Linear Prediction and Principal Components Analysis. Environmental conditions and plant populations affect the yield components of maize hybrids. Variations equal to 57,000 and 62,700 plants ha−1 was relatively small and may not have been large enough to reveal plant density effects on disease. Diseases reduced the yield of hybrids with greater susceptibility to these phytopathogens at some sites, despite the use of fungicides. The best performance for at least two yield component variables resulted in the highest yield. Microclimate control using plant populations was omitted as a management option for reducing the severity and incidence of diseases for the tested conditions in this work. The climatic conditions of agricultural sites increased the incidence and severity of diseases, mainly of Cercospora zeae maydis.