Analysis of Quantitative Traits in Two Long-Term Randomly Mated Soybean Populations: I. Genetic Variances

摘要

The genetic effects of long-term random mating and natural selection aided by genetic male sterility were evaluated in two soybean [Glycine max (L.) Merr.] populations: RSII and RSIII. Population means, variances, and heritabilities were estimated to determine the effects of 26 generations of random mating. The 10% highest yielding lines from each population were selected. Data was collected on flowering date, maturity date, plant height, lodging score, seed yield, seed weight, protein concentration (PC), and oil concentration (OC). RSII had a mean seed yield, PC, and OC of 2163 kg haa?’1, 416 g kga?’1, and 193 g kga?’1, respectively. Entry-mean heritability for seed yield, PC, and OC was estimated at 36, 68, and 57%, respectively. Theoretical response to selection was 183 kg haa?’1 and, after selection, the realized gain was 161 kg haa?’1. RSIII had a mean seed yield, PC, and OC of 2300 kg haa?’1, 416 g kga?’1, and 190 g kga?’1, respectively. The entry-mean heritability estimates for seed yield, PC, and OC were 57, 87, and 91%, respectively. Theoretical response to selection was 300 kg haa?’1 and, after selection, realized gain was an increase of 139 kg haa?’1. Despite not reaching their theoretical yield potential, the best lines from both populations compared well to check cultivars. The significant genetic variances and heritabilities observed demonstrate that the breakage of linkage blocks by long-term random mating and natural selection were effective in producing competitive lines.