Submitted to: Crop Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 6/1/2010
Publication Date: 6/16/2010
Citation: Tsilo, T., Jin, Y., Anderson, A. 2010. Identification of flanking markers for the stem rust resistance gene Sr6 in wheat. Crop Science. 50:1967-1970. Interpretive Summary: Wheat stem rust, caused by Puccinia graminis f. sp. tritici, is one of the most destructive diseases of wheat. Use of resistant cultivars is the most economic means of controlling the disease. Resistance gene, Sr6, confers broad spectrum of resistance to stem rust and the gene is present in many cultivars of wheat in US and worldwide. The identification of tightly linked DNA markers will increase the success for marker-assisted selection. Tightly linked DNA markers flanking Sr6 were identified in this study. These markers will help breeders in pyramiding of Sr6 with other stem rust resistance genes.
Technical Abstract: The stem rust resistance gene Sr6 confers a high level of resistance against a wide range of stem rust races in North America. Here, we report flanking molecular markers for Sr6 on the short arm of chromosome 2D. A population of 139 recombinant-inbred lines from the cross MN99394 x MN98550 was screened for stem rust reaction in the seedling stage. In this population, resistance to stem rust was conferred by a single gene that was postulated to be Sr6 based on parental reaction to races of Puccinia graminis f. sp. tritici and the known location of Sr6 from a previous mapping study. A partial linkage map of chromosome 2D comprised Xgwm484, Xcfd77, Xcfd43, Xwmc453, Sr6, XwPt_4381, XwPt_0330, Xgpw94049, and Xgwm102 and spanned a region of 11.3 cM. The Sr6 locus was flanked by four marker loci. Proximal to Sr6 were co-segregating loci Xcfd43 and Xwmc453 at a distance of 1.2 cM. The DArT loci XwPt_04381 and XwPt_0330 were distal to Sr6 at a distance of 2.8 cM. Breeding programs that are aimed at marker-assisted selection and pyramiding of Sr6 with other stem rust resistance genes could benefit from the availability of Sr6-flanking markers.