Recently, it was announced that a new canola variety had intermediate resistance to the newly identified clubroot pathotype 5x due to its intermediate reaction when exposed to the pathotype. The Alberta Canola Producers Commission (ACPC) and Alberta canola growers need to be provided with more details and learn more about these claims of “revolutionary” resistance to new virulent strains of clubroot by seed companies.
“The confusion arises from the fact that “intermediate” reaction or resistance is a new term for growers,” says Ward Toma, General Manager of the ACPC. “While there is an agreed definition of what an intermediate reaction to the pathogen is, there is no general agreement about what an intermediate level of resistance means for yield loss or managing the buildup of resting spores in the soil.” This situation is unlike currently accepted blackleg ratings, which clearly define “moderate resistance” and “moderate susceptibility”.
The ACPC urges the Pathology Sub-Committee of the Western Canadian Canola/Rapeseed Recommending Committee, (the organization that handles the protocols around disease rating for canola) to address this issue. Providing clarity will enable growers to understand exactly what is being introduced into the market.
“The fact that some varieties weren’t completely susceptible to the 5x pathogen is encouraging news,” says Toma. “Up to this point, everything that was exposed to it died so this result offers evidence that strong resistance may yet be found. Regardless of variety, best management practices for clubroot continue to be the application of sound rotation and sanitation in combination with genetic resistance.”
Source: Alberta Canola Producers Commission