Physiologic specialization ofPuccinia triticina, the causal agent of wheat leaf rust, in Canada in 2009

Abstract

One hundred and sixty-nine wheat leaf samples infected with leaf rust (Puccinia triticina Eriks.) were collected across Canada in 2009. Three hundred and ten single uredinial isolates were analysed for their virulence spectra. The most common virulence phenotypes identified in Canada were TDBJ (28.1%), MLDS (20.6%) and TDBG (15.8%). There were eight virulence phenotypes identified among 12 isolates from Alberta and British Columbia – the most common were TDBJ (four isolates) and MBBJ (two isolates). There were 20 unique virulence phenotypes identified among 269 isolates from Manitoba and Saskatchewan. The most common virulence phenotypes were TDBJ (30%), MLDS (23%) and TDBG (18%). In Ontario, there were 13 virulence phenotypes identified from 20 isolates – the most common were TBRK (four isolates), MCGJ (three isolates), NBBT and TDBJ (two isolates each). Each of the four isolates from Quebec was a unique virulence phenotype – TBJS, MCPS, TBHK and TBPK. In Prince Edward Island, there were four virulence phenotypes (MCQJ, MCNQ, MCQK and MHNQ) identified among five isolates. The regions were different from each other for most common virulence phenotypes, but some phenotypes were in common between western Canada and Ontario. Many phenotypes were unique to a particular region and some were not found in previous Canadian surveys. Virulence phenotypes in eastern and western Canada differed for virulence to genes Lr2a, Lr2c and Lr18.