An accurate DNA marker assay for stem rust resistance gene Sr2 in wheat
- 1.2k Downloads
The stem rust resistance gene Sr2 has provided broad-spectrum protection against stem rust (Pucciniagraminis Pers. f. sp. tritici) since its wide spread deployment in wheat from the 1940s. Because Sr2 confers partial resistance which is difficult to select under field conditions, a DNA marker is desirable that accurately predicts Sr2 in diverse wheat germplasm. Using DNA sequence derived from the vicinity of the Sr2 locus, we developed a cleaved amplified polymorphic sequence (CAPS) marker that is associated with the presence or absence of the gene in 115 of 122 (95%) diverse wheat lines. The marker genotype predicted the absence of the gene in 100% of lines which were considered to lack Sr2. Discrepancies were observed in lines that were predicted to carry Sr2 but failed to show the CAPS marker. Given the high level of accuracy observed, the marker provides breeders with a selection tool for one of the most important disease resistance genes of wheat.
We acknowledge the excellent technical assistance provided by Xiaodi Xia and thank Dr Harbans Bariana and Dr Bob McIntosh for comments and advice. We acknowledge financial support from the Grains Research and Development Corporation (GRDC) in Australia.
- Borlaug NE (1968) Wheat breeding and its impact on world food supply. In: Finlay KW, Shephard KW (eds) Proceedings of the 3rd International Wheat Genetics Symposium. Australian Academy of Sciences, Canberra, pp 1–36Google Scholar
- Hare RA, McIntosh RA (1979) Genetic and cytogenetic studies of durable adult-plant resistances in Hope and related cultivars to wheat rusts. Z Planzenzüchtung 83:350–367Google Scholar
- McFadden ES (1930) A successful transfer of emmer characters to vulgare wheat. J Am Soc Agron 22:1020–1034Google Scholar
- McFadden ES (1939) Brown necrosis, a discolouration associated with rust infection in certain rust resistant wheats. J Agric Res 58:805–819Google Scholar
- McIntosh RA, Park RF, Wellings CR (1995) Wheat rusts: an atlas of resistance genes. CSIRO Publications, East MelbourneGoogle Scholar
- Mishra AN (1992) Sources of combined adult plant resistance to stem rust and leaf rust of wheat probably derived from Sr2 complex and Lr34 complex. Ann Wheat Newsl 38:135–138Google Scholar
- Peterson RF, Campbell AB, Hannah AE (1948) A diagrammatic scale for estimating rust intensity of leaves and stems of cereals. Can J Res 26:496–500Google Scholar