Leptosphaeria maculans Isolates Reveal Their Allele Frequency in Western Canada

Blackleg, caused by , is a major disease of canola in Canada, Australia, and Europe. For effective deployment of resistant varieties and disease management, it is crucial to understand the population structure of . In this study, we analyzed isolates from commercial fields in western Canada from 2014 to 2016 for the presence and frequency of avirulence ( ) genes. A total of 1,584 isolates were examined for the presence of genes , , , , , , , , , and via a set of differential host genotypes carrying known resistance genes and a PCR assay. Several genes showed a higher frequency in the pathogen population, such as and , which were present in >90% of isolates, whereas , , and showed frequencies of