Location: Cereal Disease Laboratory
Title: Genetics and mapping of stem rust resistance in MV Zelma winter wheat Authors
Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: July 1, 2012
Publication Date: N/A
Technical Abstract: Seedling screening of winter wheat varieties identified Hungarian winter wheat cultivar MV Zelma as resistant to wheat stem rust after infection by P. graminis f. sp. tritici races TTKSK (Ug99), TTKST, TTTSK, and nine races from the United States. Though previous data suggest MV Zelma possessed stem rust resistance gene Sr38, the low infection type of MV Zelma to P. graminis f. sp. tritici races virulent to Sr38, including races TTKSK and TTTTF, indicate other resistance is present in MV Zelma. In order to determine the genetics of resistance in MV Zelma, we crossed MV Zelma to susceptible LMPG-6 and derived 94 F2:3 families. Segregation of seedling resistance to race TTKSK among and within the families indicated a single dominant gene conferred resistance. DNAs extracted from F2 plants corresponding to the F2:3 families were assayed with 9,000 genome-wide SNP markers using an iSelect assay developed by E. Akhunov and M. Hayden. A total of 7 SNP markers mapped within 6 cM of the gene for stem rust resistance. Preliminary mapping data indicated that these SNP markers mapped to 7AL. We genotyped the population with polymorphic SSRs on 7AL to confirm the chromosome arm location. Markers wmc346 and cfa2240, previously mapped to 7AL, flanked the resistance gene at 4.3 cM proximal and 10 cM distal, respectively. The data suggest that the stem rust resistance gene is on chromosome arm 7AL. Resistance genes Sr15 and Sr22 are also located on this chromosome arm. Infection type, race specificity, and map location suggest that the gene in MV Zelma is not Sr22. Infection type and map location suggest that the gene could be Sr15. Further studies will determine the allelic relationship between Sr15 and the gene in MV Zelma and also investigate the potential for pyramiding both Sr22 and the gene in MV Zelma on chromosome arm 7AL in winter wheat.