Location: Soybean and Nitrogen Fixation ResearchTitle: Analysis of Quantitative Traits in Two Long-Term Randomly Mated Soybean Populations I. Genetic Variances Author
Submitted to: Crop Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 11/12/2012
Publication Date: 4/15/2013
Citation: Recker, J., Burton, J., Cardinal, A., Miranda, L.M. 2013. Analysis of Quantitative Traits in Two Long-Term Randomly Mated Soybean Populations I. Genetic Variances. Crop Science. 53(4)pp. 1375-1383. Interpretive Summary: Random mating aid by genetic male sterility facilitates the development of populations with a broad genetic base. Populations RSII and RSIII were developed using two diverse sets of parents and were random mated without selection for 26 generations. This long term random mating offers a unique opportunity to study the effects of genetic recombination and natural selection on genetic parameters. Population means, variances, and heritabilities were estimated in both populations. Traits evaluated included: flowering date, maturity date, plant height, lodging score, seed yield, seed weight, protein concentration and oil concentration. The results showed that large genetic variances and heritabilities were maintained. Also, progeny with yields comparable to modern cultivars was obtained from both populations. This study underlines the importance of genetic recombination to produce favorable genetic variation.
Technical Abstract: 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 ha-1, 416 g kg-1 and 193 g kg-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 ha-1 and, after selection, the realized gain was 161 kg ha-1. RSIII had a mean seed yield, PC, and OC of 2300 kg ha-1, 416 g kg-1, and 190 g kg-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 ha-1 and, after selection, realized gain was an increase of 139 kg ha-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.