Evaluation of Soybean Lines for Edamame Yield Traits and Trait Genetic Correlation

Abstract

Edamame is a vegetable or specialty soybean (Glycine max (L.) Merr.) with high nutrition and market value. The market demand for edamame has significantly increased in the United States since its health and nutritional benefits became recognized. However, there are a limited number of domestically developed or improved edamame cultivars in the United States, and the knowledge of edamame is very limited. In this study, 86 breeding lines and cultivars of maturity group (MG) V and VI developed in the United States were evaluated in replicated field trials for edamame yield and agronomic traits in Virginia in 2015 and 2016. The results indicated that there were significant differences among the genotypes and between years in all the traits investigated (plant height, fresh biomass, pod yield, pod ratio, fresh seed yield, seed ratio, and 100-seed weights), but the yearly differences for dried 100-seed weight and dried-to-fresh ratio of seeds were insignificant. Genotype-by-year interaction effects were not significant in most cases. Estimates of the broad sense heritability varied with traits, from 23% to 88%. Coefficients of phenotypic and genotypic correlation were mostly low, but fresh pod and seed yields were highly correlated. Fresh biomass exhibited a positive phenotypic correlation with pod and seed yields, but the genotypic correlation coefficients were not significant. Twelve breeding lines were preliminarily identified to have greater edamame yield and desired traits. The information generated in this study will be helpful for edamame breeding and commercial production.