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Genetics

Localization of Stem Rust Resistance Genes and Associated Molecular Markers in Cultivated Oat. L. S. O’Donoughue, Eastern Cereal and Oilseed Research Centre, Agriculture and Agri-Food Canada, Ottawa, ON K1A 0C6, Current address: DNA LandMarks, Inc., C.P. 6, St-Jean sur Richelieu, QC J3B 6Z1, Canada; J. Chong(2), C. P. Wight(3), G. Fedak(4), and S. J. Molnar(5). (2)Cereal Research Centre, Agriculture and Agri-Food Canada, 195 Dafoe Road, Winnipeg, MB R3T 2M9; (3)(4)(5)Eastern Cereal and Oilseed Research Centre, Agriculture and Agri-Food Canada, Ottawa, ON K1A 0C6. Phytopathology 86:719-727. Accepted for publication 13 March 1996. 1995 Department of Agriculture and Agri-Food, Government of Canada. DOI: 10.1094/Phyto-86-719.

Molecular markers have been identified in cultivated oat for the Pg9 and Pg13 loci conferring resistance to different races of the stem rust pathogen, Puccinia graminis f. sp. avenae. Near-isogenic lines and bulked segregant analysis were used to identify putative restriction fragment length polymorphism (RFLP) and random amplified polymorphic DNA markers. Linkage relationships were established in segregating populations derived from crosses of OT328 with Dumont (segregating for both Pg9 and Pg13), Rodney 0 with Rodney 0-Pg9 (segregating for Pg9), and Rodney 0 with Rodney 0-Pg13 (segregating for Pg13). The 5 markers linked to Pg9 exhibited from 0 to 2.7% recombination with the resistance locus, and the 11 markers linked to Pg13 exhibited from 0 to 22.7% recombination. An oat avenin clone detected a RFLP marker linked to the Pg9 locus and an oat globulin clone detected a RFLP marker linked to the Pg13 locus. Comparative mapping with an existing molecular linkage map of cultivated oat permitted localization of the Pg9 and Pg13 stem rust resistance genes. This is the first report of the localization of stem rust resistance genes on the linkage map of cultivated oat.