Correlations of yield and quality traits between immature and mature seed stages of edamame soybean

Breeding programs must harvest edamame soybean [Glycine max (L.) Merr.] at the immature (R6) stage for yield and quality determinations, and at the mature (R8) stage for seed-source purposes. If correlations of important breeding traits between the R6 and R8 stages were strong, breeders could perform indirect selection, at least during early stages in the breeding process, thus saving resources and time. The objective of this research was to estimate correlation coefficients between the R6 and R8 stages of edamame for key traits, including yield, texture, protein, mineral, and soluble sugar content. Three edamame lines and a conventional cultivar were grown at two Arkansas locations for 3 years. Correlation coefficients were strong and positive between the R6 and R8 stages for protein (r = 0.74), iron (r = 0.73), and texture (r = 0.72), and moderate and positive for yield (r = 0.67), sucrose (r = 0.58), and calcium (r = 0.57). In conclusion, breeders could perform indirect selection for high yield, soft texture, and high protein and sucrose contents using mature seeds.