Analysis of Historical Genetic Diversity in the University of Guelph Soybean Breeding Program

Understanding historical patterns of genetic diversity within the germplasm of a breeding program allows breeders to make informed decisions for future crosses and selections. To characterize germplasm diversity in the University of Guelph soybean breeding programs, a panel of 296 lines was genotyped using genotyping-by-sequencing to produce 40307 SNPs across the panel. This pedigree panel consists of 200 lines from the University of Guelph main campus breeding program (maturity groups 1, 0 and 00) and 96 lines from the Ridgetown campus breeding program (maturity groups 1 and 2). The panel was chosen from pedigree records to consist of founder germplasm, historical lines, modern elite cultivars and current experimental germplasm ranging from 1918 to 2016. A range of agronomic and seed trait data has been collected from two-location, two-year field trials in southwestern Ontario. Diversity within the Guelph campus breeding program for agronomic traits and markers will be discussed with historical trends in breeding efforts highlighted. Six distinct genetic clusters within the panel have been identified. Yield gains for commercial cultivars released from the Guelph breeding program since 1990 were estimated at 28 kg ha^-1 year^-1 across all maturity groups. Significant marker-trait associations for negatively-correlated stachyose and raffinose were found on Ch18 and Ch20.