Genetic analysis of edamame seed composition and trait relationships in soybean lines

Abstract

Edamame, a vegetable or specialty soybean (Glycine max) with high nutritional and market value, is relatively new to North America. Because of its health and nutritional benefits and globalized trade, the edamame market and acreage in the United States are steadily increasing. To facilitate edamame breeding and commercial production, we genetically analyzed edamame seed composition using 86 breeding lines and cultivars developed in the U.S. Significant genotypic differences based on a single year or 2-year joint analysis were observed for most traits investigated, including protein, oil, dietary fiber, starch, sucrose, stachyose and total sugar content. No significant genotypic difference was observed for ash content in both years and for raffinose content in year 2016. Yearly differences were also significant except for sucrose, stachyose and total sugar. Genotype-by-year interaction was significant for protein, sucrose, raffinose and total sugar, but insignificant for other traits. The heritability was high and relatively stable for protein and oil content, followed by stachyose content, but was low for ash and starch content. The heritability for sucrose, total sugar and dietary fiber content varied from 38 to 75%. Genotypic correlations were insignificant among most traits. However, protein content was negatively correlated with oil content and dietary fiber, but positively associated with stachyose. Oil content was negatively correlated with starch and individual sugars. Although positive phenotypic or Pearson’s correlation existed between total sugar content and individual sugars, and between sucrose and starch content, their genotypic correlations were insignificant.