2007 Annual Report 1a.Objectives (from AD-416) Identification and utilization of exotic germplasm to improve soybean productivity. 1b.Approach (from AD-416) This project will make crosses and develop populations utilizing exotic germplasm and experimental lines derived from exotic germplasm as parents, test experimental lines and populations derived from exotic germplasm in maturity groups III, IV, and V, and exploit new genetic technology to develop high yielding experimental lines and accelerate the rate of yield improvement in the U.S. soybean cultivars. 3.Progress Report This report serves to document research conducted under a Specific Cooperative Agreement between ARS and the University of Georgia. Additional details may be found under the parent project 3611-21000-018-00D, Soybean Genetic Resources Management and Utilization. An analysis of the yield QTL in the Benning x Danbaekkong mapping population was completed. This population consists of 150 F6-derived lines that have been evaluated for seed yield in six locations. A major yield QTL was found on LG I. Lines homozygous for the Benning allele at this QTL were 200 kg/ha higher in yield than lines homozygous for the Danbaekkong allele. This is the same genomic region that contains a major protein QTL. Danbaekkong averages 52% protein compared to 42% for Benning. Two significant yield QTL were found on linkage group (LG) A1 and LG F. At both yield QTL the positive alleles where contributed by Danbaekkong. On LG A1, lines homozygous for the Danbaekkong allele averaged 150 kg/ha higher in yield than the lines homozygous for the Benning allele. On LG F, the lines homozygous for the Danbaekkong allele averaged 130 kg/ha higher in yield than the lines homozygous for the Benning allele. In cooperation with Perry Cregan, we are using SNP markers to saturate the genomic regions surrounding the yield QTL on LG A1 and LG F. The addition of these SNP markers to our genetic linkage map of this population will help refine the location of these two yield QTL. The highest yielding lines in this experiment were equal in seed yield to the check varieties NC-Roy and Boggs. Based on data from two replicated Georgia tests, six MG VII breeding lines that trace 25% of their pedigree to PI 416937 were equal or greater in yield than the check cultivars. In the USB Diversity 6 Test grown at Athens GA, two breeding lines with 50% of their pedigrees tracing to PI parents yielded within 130 to 200 kg/ha of the check cultivars Dillon and 5601T. All entries in the USB Diversity 4, 5, 6, and 7/8 tests for Asian soybean rust resistance in the Attapulgus GA field nursery. Although some differences were noted, none of the breeding lines possessed a high level of resistance to the Asian soybean rust. Data on resistance to the southern root-knot nematode were collected in the greenhouse for all entries in USB Diversity 4, 5, 6, and 7/8 tests. The highest percent of lines with resistance to southern root-knot nematode was found in the USB-Diversity 7/8 test. This result was expected based on the high percent of these lines with a known resistant parent. There were not any resistant breeding lines identified in the USB-Diversity 4, 5, 6 or 7/8 tests that did not possess a known southern root-knot nematode resistant parent. Activities of this project are monitored through quarterly reports, an annual planning meeting, and periodic phone calls and e-mails.