Soybeans are the most important source of protein for animal feed be processed into a soybean meal of 48% protein content and the nutritional quality of soybean meal is compromised by a low concentration of the sulfur amino acids. Although breeding efforts to increase protein content have been successful, yield and oil content are often negatively affected. In this project, breeding programs from seven states will work in close collaboration to gain a better understanding of the underlying genetic mechanisms that control protein content and amino acid composition in soybean seed and to incorporate this knowledge into applied breeding programs that target a wide range of maturity groups. The long term goal of this project is to release commercially viable varieties with protein content at 36-38% (13% moisture content), to consistently achieve protein-meal at 48%; with a minimum oil content of 18%.
Soybean meal provides a high-protein feed ingredient that is used predominantly in poultry and swine production. The use of soy meal by those end-users could grow at about 5 MMT/year, ultimately reaching around 230 MMT in 2020 (Wilson, 2010). Soybeans with insufficient protein content cannot be processed into soybean meal with 48% protein content and are less valuable as a feeding ingredient. Recently, several successful attempts to develop soybean germplasm with high protein content have been reported (Mian et al., 2008; Carter et al., 2010; Chen et al., 2011); however, in all cases, the yields were not comparable to commercial cultivars. The negative correlations between protein and oil content, and their individual or combined negative effect on seed yield have been major constraints to the development of high-protein and high-oil soybean lines without reductions in seed yield. Despite this, a recent study by Eskandari et al. (2013) suggests that small simultaneous progress in both traits might be possible. In this research, QTL alleles with small positive effects for seed protein and oil concentration, and no negative effect on yield, were identified in a population derived from the cross between two moderately high oil soybean cultivars. Also, a major QTL from the Korean PI Danbaekkong has been reported to increase protein up to 4 percentage points without any loss in seed yield in the southern USA (Yates and Boerma 2006).