Submitted to: Soybean Genetics Newsletter
Publication Type: Popular Publication
Publication Acceptance Date: 4/10/1999
Publication Date: N/A
Technical Abstract: Partial resistance to Sclerotinia sclerotiorum was identified in soybean accessions and cultivars in the United States. The objectives of this study were to: (i) estimate the number of genes contributing to resistance to S. sclerotiorum in the soybean cultivars Asgrow A2506 and Novartis S19-90 and (ii) estimate broad and narrow sense heritabilities. Data from greenhouse evaluations of three crosses, Asgrow WR2347 x Asgrow A2506, Novartis S19-90 x Asgrow A2506, and Novartis S19-90 x Asgrow WR2347, were used to estimate goodness of fit for theoretical inheritance models in F2 and F3 generations and to estimate heritabilities. We found significant results indicating partial resistance to S. sclerotiorum is caused by multiple genes and some may be recessive. Estimates of heritabilities indicated more dominance occurred when Novartis S19-90 was used as a parental line compared with Asgrow A2506. All heritability estimates based on F2:3 family means were higher than the heritability estimates based on F2 plant basis. The selection for partial resistance to S. sclerotiorum in soybean based on F2:3 family means evaluation would be more efficient than selecting on a single F2 plant basis. The high heritability estimates in our greenhouse evaluations are valuable to soybean breeders selecting for partial resistance to S. sclerotiorum.