Genotype and environment influence on protein components of soybean

The quality of some soybean [Glycine max (L.) Merr.] food products has been associated with the content of some components of the protein fraction of the seed. The objective of this study was to determine the role of genotype, environment, and genotype X environment interactions on the components of beta-conglycinin (betac) and glycinin (G). The traits were measured on 14 cultivars of Maturity Group 11 grown in three replications at each of eight locations throughout Iowa in 1998, 1999, and 2000. Cultivars were significantly different for all traits, except the A, subunit of G. No significant interactions were found for cultivars with years or locations for betac, G, or the G/betac ratio, which indicated that the relative performance of cultivars across environments was consistent. No significant differences were expressed among years or locations for Pc, G, and the G/betac ratio; however, there were significant differences for the three traits among the 24 environments. There was a significant phenotypic correlation of -0.92 between the Pc and G contents of the 14 cultivars averaged across environments, but no significant correlations of betac, G, or the G/betac ratio with protein and oil content. It should be possible to breed for desired levels of the protein components in a cultivar development program and to select among cultivars for the traits in commercial grain production.