Assessment of <i>Brassica</i> genotypes to enhance the Canadian Clubroot Differential set

Plasmodiophora brassicae pathotypes in Canada are generally identified using the Canadian Clubroot Differential set. The doubled haploid Brassica napus lines ACS-N39 and LCF-1 were evaluated as potential replacements for the universally susceptible Brassica rapa ‘Granaat’ and the resistant B. napus hybrid ‘45H29’. LCF-1 effectively differentiated resistant and susceptible responses across 10 pathogen isolates, with no differences in average disease severity among the resistance-breaking isolates. Clubroot severity was lower in ACS-N39 than in ‘Granaat’. We conclude that LCF-1 can directly replace the resistant differential ‘45H29’, while ACS-N39, though susceptible, is less so than the current universally susceptible check, ‘Granaat’.