Leandro Mozzoni, University of Arkansas, University of Arkansas, 115 PTSC Bldg, Fayetteville, AR 72701 and Pengyin Chen, 115 Plant Science Bldg, University of Arkansas, University of Arkansas, Dept of CSES, Fayetteville, AR 72701.
Vegetable soybean is harvested when seeds are fully developed but still immature and green in color. Breeding for vegetable soybean, therefore, presents the challenge of working at both immature and mature physiological stages. Vegetable soybean lines are usually harvested at the R6 stage for pod yield and seed quality composition analysis. Also, each line should be grown and harvested at the R8 stage for seed increase purposes, resulting in extra breeding costs. The objective of this research was to assess the correlations of pod yield and quality traits between the R6 and R8 stages, in order to facilitate the breeding of vegetable soybean by postponing the yield and quality tests at immature stages to the advanced stages of the breeding program. Two year data indicated a positive correlation for yield, protein and sucrose content between R6 and R8 stages. Additionally, there was no change in the ranking of vegetable soybean lines between the R6 and R8 stages. In contrast, there was no correlation for seed texture and raffinose+stachyose content. In conclusion, vegetable-type soybean lines can be evaluated at the R8 stage and selected for high yield, high protein and high sucrose contents. The results from R8 analysis can be then confirmed by testing fewer genotypes at R6 stages at later stages of the breeding program, thereby reducing the breeding costs.