Analysis of a Quantitative Trait Locus Allele from Wild Soybean That Increases Seed Protein Concentration in Soybean

Increases in the seed protein concentration of soybean [Glycine max (L.) Merr.] would improve the value of the crop. Two major quantitative trait locus (QTL) alleles from Glycine soja Sieb. and Zucc. that increased seed protein concentration were identified previously. The first objective of our study was to test the two G. soja QTL alleles in a population developed through backcrossing the alleles into a soybean background. The second objective was to evaluate the effect of one of the G. soja QTL alleles in three genetic backgrounds. A backcross three (BC3) population was developed and evaluated in the field across two locations over 2 yr. To test the allele in different backgrounds, a line from the backcross population was crossed to three soybean genotypes. Populations developed from these crosses were then evaluated in three field environments. In the backcross population, genetic marker alleles linked to the QTL allele from G. soja on linkage group (LG) I were significantly (P < 0.05) associated with greater protein and less oil concentration, reduced yield, smaller seeds, taller plants, and earlier maturity than the G. max alleles. Markers linked to the second G. soja QTL allele on LG E were not significantly associated with seed or agronomic traits. In the genetic background tests, markers linked to the G. soja QTL allele on LG I were associated with an increase in protein concentration in two of the three crosses. These results show that seed component traits can be successfully modified through genetic mapping coupled with marker assisted selection.