| Simple sequence repeat (SSR) markers were used to identify possible ancestors of current soybean cultivars or select individuals carrying a particular marker genotype in a backcross program. The use of transgenes to enhance resistance to Sclerotinia sclerotiorum in soybean was also investigated. Finally, the effects of genetic transformation in the seed storage protein profile of transgenic soybeans were evaluated by sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE).; Nineteen SSR markers putatively linked to quantitative trait loci (QTL) for resistance to S. sclerotiorum had been identified in soybean cultivars 'Corsoy 79', 'Dassel', 'Vinton 81', 'DSR173' and 'NKS 19-90'. We used those linked markers to trace the origin of the marker alleles and QTL alleles in a pedigree study. In three cases the most likely source(s) of marker allele and QTL was determined. The favorable Satt424 marker allele on linkage group A2 in Corsoy 79 probably originated from Mandarin, Satt114 on linkage group F in NKS 19-90 and Corsoy 79 most likely came from PI257.435, and Sat_109-Satt243 flanking a QTL on linkage group O in NKS19-90 and Vinton 81 probably originated from Mandarin or Mandarin Ottawa.; Markers Satt114, Sat_109 and Satt243 were employed for tracking the QTL linked to them in a marker assisted introgression program. The donor parents NKS19-90 and Vinton 81 were backcrossed to 'Williams 82'. Successful introgression of the QTL from Vinton 81 was achieved since backcross progenies carrying marker alleles Sat_109 and Satt243 from Vinton 81 were more resistant than Williams 82. Introgression of QTL from NKS19-90 was prevented by recombination between marker allele and QTL and the reduced number of individuals recovered in each backcross generation.; Transferring the oxalyl-CoA decarboxylase gene from Oxalobacter formigenes into NKS19-90 and Vinton 81 did not improve resistance to the pathogen in these cultivars. It is hypothesized that a second gene of the oxalate degradation pathway is required.; Quantitative differences in the amounts of a subunits of beta-conglycinin were detected between transgenic high-oleic soybeans, transformed with the FAD2-1 and Fat B genes under control of beta-conglycinin promoter, and their wild type counterparts. |
