Mapping Resistance in Oat to Puccinia graminis f. Sp. avenae Races TQL and KBD

In seedling tests, the Canadian oat cultivar CDC Boyer showed a resistant infection type of ‘2’ to Puccinia graminis f. sp. avenae (Pga) races TQL and KBD. To elucidate the inheritance of resistance to these two Pga races, two populations generated from crosses between CDC Boyer and susceptible parents were available: Provena/CDC Boyer and CDC Boyer /94197A1-9-2-2-2-5. The parents and RIL populations were tested at the seedling stage against Pga races TQL and KBD. Chi square ratios of 1R:1S indicated that one gene in CDC Boyer conditioned seedling resistance. A newly developed iSelect SNP genotyping platform containing 5744 oat SNP markers was used to genotype the parents and RIL populations. Resistance to TQL and KBD mapped to the same locus on the long arm of chromosome 17A. The stem rust genes, Pg1, Pg2, Pg4, Pg9, and Pg13 have been used widely in Canada to control oat stem rust. Of these genes only Pg9 and Pg13 are effective against Pga race TQL and thus the resistance in CDC Boyer could be either Pg9 or Pg13or possibly a new resistance gene