S1.4: Large-scale population survey of Leptosphaeria maculans in France highlights both on-going breakdowns and potentially efficient resistance genes in rapeseed

Abstract: A large population of L. maculans, cause of stem canker of oilseed rape, was sampled at 11 sites in France in 2019 and 2020. This population was phenotyped for its virulence against nine Brassica napus resistance genes. The frequency of virulent alleles was compared to that of previous population samples and indicated that three resistance genes, Rlm6, Rlm11 and LepR2 (RlmS) are still very effective against L. maculans in France.