Seed Protein and Oil QTL Mapping in Three Backcross Soybean Populations.
Sarah J. Schultz, Univ. of Illinois, Urbana, IL 61801 and Randall L. Nelson, USDA-ARS/Univ. of Illinois, Urbana, IL 61801.
Soybean seed has the highest concentration of crude protein among all sources of vegetable protein. Currently, soybean meal accounts for two-thirds of the total value of the seed. The objectives of this study were to identify QTL associated with protein and oil in backcross populations and to assess genetic variability among high protein sources based on identified QTL. Three backcross populations were used: Williams 82 (2) x PI 407788A (pop 407), Williams 82 (2) x PI 423948A (pop 423), and Williams 82 (2) x PI 437088A (pop 437). All populations were grown in 2005 with two replications at three locations in east central Illinois. Pop 407 had 125 BC1F5-derived lines, pop 423 had 129 BC1F5-derived lines, and pop 437 had 165 BC1F5-derived lines. All tests included parental checks and the donor PI. Approximately 100 polymorphic simple sequence repeat (SSR) markers were used to genotype each population. Protein and oil concentrations were measured with near-infrared reflectance spectroscopy. Gmendel was used to construct a genetic map for each population and JoinMap was used to create one map for all populations. Composite interval mapping was done using PlabQTL.