Genetic Diversity of Korean Black Soybean (Glycine max L.) Germplasms with Green Cotyledons Based on Seed Composition Traits

Abstract

The demand for black soybeans (Glycine max (L.) Merr.) with green cotyledons is increasing because of their health benefits. Therefore, it is important to understand the genetic diversity of black soybean germplasms and to develop a new soybean cultivar. This study aimed to evaluate genetic diversity among 469 black soybean germplasms with green cotyledons based on seed composition traits. Twenty seed composition traits were analyzed to conduct correlation analysis, principal component analysis (PCA), and cluster analysis, which indicated that black soybean germplasms were divided into four clusters. Black soybean germplasms in cluster 1 had higher crude fat, lutein, chlorophyll a, chlorophyll b, and total chlorophyll contents, but lower cyanidin-3-glucoside content than those in clusters 2 and 3. However, germplasms in clusters 2 and 3 had the highest cyanidin-3-glucoside content. Moreover, germplasms in cluster 1 had significantly higher palmitic acid content than those in clusters 2 and 3. Germplasms in clusters 2 and 3 had relatively high α-linolenic acid content. Germplasms in cluster 4 had the highest oleic acid content. This study highlights the genetic diversity of black soybean germplasms with different seed composition traits, and the results of this study can be beneficial for soybean breeding programs, enabling them to develop new black soybean cultivars with green cotyledons and improved seed composition traits.