Effect of the mutant Danbaekkong allele on soybean seed yield, protein, and oil concentration and amino acid composition
Cunicelli, M. J., H. Bhandari, P. Chen, C. E. Sams, M. A. R. Mian, L. Mozzoni, C. Smallwood, and V. R. Pantalone.  2018.  Crop Science Society of America, ASA-CSSA Annual Meeting, November 4-7, 2018, Baltimore, MD.

Soybean [Glycine max (L.) Merr.] is the world’s leading source of vegetable oil and high quality protein meal. Soybean protein and oil concentrations as well as protein and yield are negatively correlated. For this reason, it is a challenge for plant breeders to increase soybean protein concentration while maintaining oil concentration and yield. The objective of this study was to determine if marker assisted selection for the Danbaekkong (Dan) protein allele on chromosome 20 can be used to select for agronomic and seed quality traits in genetic backgrounds of interest. A cross between G03-3101 and LD00-2817P led to a population of 24 F8:10 (2016) and F8:11 (2017) near isogenic lines (NILs) of soybean grown in a two year field trial. The 24 NILs were composed of 12 wild type (WT) and 12 mutant Dan type. These NILs were grown over the 2016 and 2017 field seasons in replicated nine location field trials with six locations in Tennessee and one each in Arkansas, Missouri, and North Carolina. As predicted, there were significant differences in yield, protein, and oil concentrations between the two experimental groups (p < 0.05). The Dan experimental group had the lower yield values, ranging from 3030-3273 kg ha-1. The Dan experimental group had significantly more protein (421.6 g kg-1) and less oil (192.3 g kg-1) than the WT group (390.4 g kg-1 protein and 210.8 g kg-1 oil) (p < 0.05). These results corroborate the negative genetic correlation between both protein and oil and protein and yield and support previous research. However when the top 25% for yield were selected from within the Dan group, their yield (3,260 kg ha-1) was equivalent to that of the WT group (3,281 kg ha-1) and their protein concentration (422 g kg-1) was significantly higher than the WT group (390 g kg-1). The five amino acids tested were significantly (p < 0.05) lower in the Dan group compared to the WT group. While protein concentrations of Dan NILs were elevated, there were significant reductions in oil, yield, and amino acid concentrations, although selection of specific individuals within the Dan group led to high yield.