Inheritance of Grain Quality and Days to Flowering in Vegetable Soybean

Grain quality and days to flowering are major characters to be considered in vegetable soybean improvement. The objective of this study was to investigate the inheritance of both traits in recombinant inbred lines (RILs) derived from a cross between the vegetable soybean cultivar ‘AGS292’ and the grain soybean line (G8891xG7945)-31-3-5-5 (or ‘K3’) grown in two environments. The traits under study were total soluble solids content (TSS) of green seed, days to flowering (DTF), and seed weight (SW). The RIL population distributed normally with respect to the traits, suggesting that they are quantitative ones. A significant positive transgressive segregation of TSS content was also observed. The narrow sense heritabilities of TSS, DTF and SW in two environments were 58.2 vs 65.2, 91.6% vs 94.2, and 75.4 vs 90.5%, while the combined estimates across two environments were 45.5, 29.1, and 62.0%, respectively, This indicated that the heritabilities of DTF and SW were not consistent across the environments. The negative correlation between DTF with TSS and SW were found. The results obtained in our study can serve as a basic information for breeding to improve the quality traits of vegetable soybean in Thailand and her neighboring countries.