Comparing yield trial locations based on their elicited expressions of genetic variance among soybean cultivars

Abstract

AbstractMain considerations for yield trial site selection are the ability to discriminate among genotypes, minimize redundancy, and generate a genotype × environment interaction representative of the targeted market region. The objective was to utilize soybean (Glycine max L.) variety trial results of five relative maturity group (MG) tests at five Tennessee locations spanning 14 yr to compare test location uniqueness and/or redundancy via genetic variance estimates (estimated as twice the genetic variance among homozygous lines) and cluster analysis. Principle components analyses allowed for location comparisons of genetic variance expression among cultivars in different MG tests. Individual location, test, and year genetic variance estimates ranged from < 1–285 (Mg ha−1)2. Years and locations affected the magnitude of genetic variance, with years largely driving genetic expression within MGs in these environments. Location‐induced effects were likely owing to different MGs experiencing soil moisture and temperature (day and nighttime) at varying maturity stages. Within a given location, the magnitudes of genetic variance estimates were similar among the five MGs, illustrating that glyphosate‐tolerant and nontolerant cultivars had similar genetic variability. There were three sets of three locations that consistently provided nonredundant genetic expression, with two locations being duplicative. These results indicate that four of the five locations are needed, and one location could be eliminated without compromising cultivar yield trial information for five MG tests. Such analyses are worthwhile for comparing yield trial locations for their discriminating ability and representativeness that are essential for a robust variety test program within a targeted region.