Effects of Genotype × Environment Interaction on Agronomic Traits in Soybean

Genotype × environment interaction influences the market value of soybean [Glycine max (L.) Merr.] protein, oil, and fatty acid traits. The objectives of this research were (i) to evaluate agronomic trait performance and stability of soybean genotypes in individual environments and across environments; and (ii) to evaluate the relationship of test environments for selecting superior genotypes within the mega‐environment for soybean production in the southern region of Wisconsin. A total of 68 soybean genotypes were selected from University of Wisconsin soybean evaluation trials and grown at four locations in 2003 and 2004. Soybean genotypes, grown in trials with conventional and Roundup Ready herbicide treatments were analyzed for yield, protein, oil, and the fatty acid components palmitic acid, stearic acid, oleic acid, linoleic acid, and linolenic acid. Repeatability estimates among genotypes ranged from 0.27 to 0.98 with yield and the fatty acid component linolenic acid being the most sensitive to environment effects. Superior genotypes could be consistently selected for yield, protein, oil, and fatty acid components using biplot analysis and stability estimates. Among locations in the southern region in Wisconsin, Arlington provides unique information for soybean fatty acid evaluations, but similar information about soybean yield, protein, and oil with Janesville or Lancaster. So, if soybean fatty acid is not important then Arlington could be dropped as a test site.