Early Maturity Soybean Production System: Genotype × Environment Interaction between Regions of Adaption

Abstract

An early soybean [Glycine max (L) Merr.] production system involves growing soybean cultivars of a maturity group earlier than those that utilize the full growing season. It is proposed as a hedge against drought stress that has contributed to a large reduction in the soybean production area in the southern USA during the last decade. The objective of this study was to compare the magnitude of genotype × environment interactions within and between regions of full season and less than full season adaptation. Thirty‐two Maturity Group I genotypes were evaluated in four environments in both Kentucky (KY) and Minnesota (MN). For yield, within state genotype × environment interactions were significant in both states whereas the genotype × state interaction was not significant. Within and between state interactions were all significant for seed protein and oil concentrations. In all cases, the percentage of possible genotype × environment crossover interactions that were significant was <10%. The yield response in KY to correlated selection in MN was predicted to be 0.94 as efficient as direct selection in KY, and the response to simulated selection at 25% selection intensity was equal for MN and KY selection. In light of this similar genotype performance between states, we recommend not initiating new breeding programs for genotypes specifically adapted to an early soybean production system.