Submitted to: Crop Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 9/20/2003
Publication Date: 5/15/2004
Citation: Kabelka, E.A., Diers, B.W., Fehr, W.R., Leroy, A.R., Baianu, I.C., You, T., Nelson, R.L. 2004. Putative alleles for increased yield from soybean plant introductions. Crop Science.44: 784-791. Interpretive Summary: The genetic base of commercial soybean production in the U.S. is very narrow and less than 1% of the lines that exist in USDA Soybean Germplasm Collection has been used in soybean breeding. Using DNA markers in a set of inbred lines derived from crossing a commercial cultivar with an experimental line derived from exotic germplasm, we found two chromosome segments that were consistently associated with higher yield in all lines tested and at all locations tested. In both cases the chromosome segment associated with higher yield originated in exotic germplasm that has not been previously used in U.S. soybean breeding. These results will be of interest to soybean breeders and to other scientists interested in the genetics of seed yield.
Technical Abstract: Improving seed yield of soybean [Glycine max (L.) Merr.] cultivars is an important goal of breeding programs. The objective of this study was to evaluate two soybean plant introductions (PIs) as sources of alleles for the enhancement of seed yield in North American cultivars. A soybean population derived from a cross between ‘BSR 101’ and the experimental line LG82-8379 was evaluated with simple sequence repeat (SSR) markers and in field tests to identify quantitative trait loci (QTL) associated with seed yield and other agronomic traits. The pedigree of BSR 101 has nine of ten ancestral lines that have made the greatest contribution to the commercially used gene pool of North America, while LG82-8379 was selected from a cross between two soybean PIs, PI 68508 and FC 04007B. One hundred sixty-seven F5-derived lines developed from this cross were evaluated for segregation at 145 polymorphic SSR marker loci that were estimated to cover approximately 82% of the soybean genome. The lines, divided into three sets based on maturity, were evaluated for seed yield, days to flower, days to maturity, reproductive period, plant height, lodging score, and seed protein and oil concentration in 12 environments. Significant (P<0.05) variation within lines of each set was present for all traits. Using single-marker trait and composite interval mapping methods, 15 QTL were significantly (P<0.05, LOD>2.5) associated with seed yield in at least one set. Two were found significant in combined analysis of all lines across all sets. At nine of the yield QTL, the LG82-8379 alleles enhanced seed yield 47 to 148 kg ha-1, an increase of 1.7 to 5.4% over the BSR 101 alleles. Of these nine, four were traced to FC 04007B (including the two QTL across sets) while five were traced to PI 68508. At the remaining six yield QTL, the BSR 101 alleles enhanced seed yield 67 to 128 kg ha-1, an increase of 2.4 to 4.4% over the LG82-8379 alleles. Four yield QTL were associated with days to maturity, eight with plant height, and three with seed protein concentration. Additional independently segregating QTL were identified for days to maturity, plant height, lodging, and seed protein and oil concentration. These results indicate that soybean PIs have the genetic potential for improving seed yield in U.S. soybean cultivars.