Hollman’s team found 25 unique clubroot pathotypes within the samples.
Of those 25, 15 can overcome resistance.
Researchers also found seven new pathotypes, six of which can bypass canola’s bred resistance.
“Finding new pathotypes is a trend we’ve been seeing over the years,” Hollman told Farms.com.
Farms.com connected with Hollman in 2021 when research she participated in discovered nine new clubroot pathotypes. That work brought the total number of known clubroot pathotypes up to 36.
This most recent research shows how much diversity there is in the clubroot pathogen, Hollman said.
“It is quite significant that we’re at a point where there’s more resistance-breaking pathotypes than not being found,” she said. “It’s going to be difficult for breeders to keep up with the evolution of this pathogen.”
Getting clubroot under control will require a whole of industry approach, Hollman says.
Keisha Hollman.
“Everyone kind of has an obligation to practice good genetic stewardship,” she said. “Researchers are putting in work, producers are putting in work through management strategies, and breeders are going to be putting in work as well.”
Breeders can use the information from Hollman’s research, available in the Canadian Journal of Plant Pathology, she added.
The message the research sends to farmers is to consider integrated management strategies.
Scouting, early detection and other steps will be important to reduce clubroot’s spread, Hollman says.
“Like many things in agriculture, implementing or improving these strategies costs money,” she said. “So farmers are going to have to weigh those costs versus the potential costs of doing nothing.”