Large-scale population survey of Leptosphaeria maculans in France highlights both on-going breakdowns and potentially effective resistance genes in oilseed rape.

Background: Leptosphaeria maculans, the cause of stem canker of oilseed rape, develops gene-for-gene interactions with its host and shows a high evolutionary potential to 'break down' novel resistance genes (R, Rlm) deployed in cultivars over large areas. For optimal management of R genes, updated knowledge of the population structure of the pathogen is needed. In France, large-scale surveys have been done at 10-year intervals since 2000.