Physiological bases of across - environment and environment - specific responses for grain yield in maize hybrids obtained from a full diallel mating design

Genotype x environment interaction explains a proportion of variation for crop yield performance often higher than the genotypic effect, becoming a major impediment to genetic progress. In this study, a crop model of yield determination in combination with three - mode principal component analysis (PCA) was used to analyze genotype x environment x attribute interaction. A full diallel of six maize (Zea mays L.) inbred lines was grown in 10 environments in Argentina. The first environment component associated with the common genotype and attribute pattern across environments revealed that the main numerical determinant of plant grain yield (PGY) was kernel weight and not kernel number per plant (KNP). The second environment component established the importance of genotype x year interaction for anthesis-silking interval (ASI), KNP, and PGY when water deficit prevailed during the critical period of yield determination and revealed a lack of association between ASI and ear growth rate during this period. The three - mode PCA described the specific patterns of hybrid performance across environments, revealing physiological processes that separate inbred lines that contribute to drought tolerance, but at the expense of limiting PGY under well - watered conditions. The use of a crop growth model allowed interpretation of the effects of environment conditions on main physiological determinants of grain yield, exposing the effects of water supply/demand ratio as a possible driver of differential performance of inbred lines.