New variety offers protection against evolving clubroot

Canterra Seeds says CS2000 performs better than existing varieties, which are susceptible to new clubroot strain in Alberta

Canterra Seeds is launching the first hybrid canola that is resistant to the latest strain of the clubroot pathogen.

CS2000 has intermediate resistance to the 5X pathotype that was discovered in pockets of one field in the Edmonton area in 2013.

Canterra president David Hansen said growers will be able to buy seed in time for this planting season.

“We had an aggressive seed production strategy and we will have seed available in somewhat limited volumes, but we will certainly have it available for this spring,” he said.

Hansen anticipates enough demand to seed 200,000 acres of the variety this year, with the vast majority of that coming from the clubroot infected areas of Alberta.

“CS2000 is a huge step forward for growers battling clubroot,” he said.

Stephen Strelkov, plant pathologist with the University of Alberta, had a more muted assessment.

“It’s an incremental step,” he said.

Strelkov uses an index of disease severity to rank the resistance of new varieties.

A variety with a disease severity that is less than 30 percent of a highly susceptible check is considered resistant, one in the 30 to 69 percent range has intermediate resistance and higher than 70 percent is susceptible.

“(CS2000) wasn’t resistant in the sense that it still had a significant amount of disease, but the disease that it had was significantly lower than for a completely susceptible check,” he said.

“It’s certainly a step in the right direction, but it’s not a silver bullet.”

Strelkov said 27 fields in the Edmonton area had unexpectedly high levels of clubroot infection last year, considering growers had planted resistant varieties.

Samples from those fields are being tested under greenhouse conditions to see if they contain the 5X pathotype or other new strains of the disease.

“Some of the preliminary results from what I’ve seen seem to suggest that there’s at least a couple more fields,” he said.

He hopes to have complete results of the greenhouse trials by early March.

Clint Jurke, agronomy director with the Canola Council of Canada, was pleased to hear about Canterra’s new offering.

“This is a very welcome tool for us to utilize because up until now it was not looking so good,” he said.

Other clubroot resistant varieties are on the market, but they are resistant to the existing 2, 3, 5, 6 and 8 collection of pathotypes.

The discovery of 5X in 2013 was a red flag to the industry that the clubroot pathogen can change and overcome the existing resistance.

Jurke suspected 5X was always lurking in the soil, but at undetectable levels until it flourished with the introduction of varieties resistant to the more prevalent pathotypes.

“It had the opportunity to increase in the field because it was the only one that could survive on resistant varieties,” he said.

“If we’re not careful, we could see this new pathotype become established in a number of fields across Alberta, and the resistance we are currently using right now will become ineffective very quickly.”

Jurke is stunned that a resistant variety is already hitting the market less than a year after the council announced the discovery of the 5X strain last April.

“I thought we would be looking at three to four years before we would see something come to market. This is a welcome surprise,” he said.

Hansen said it was also a surprise to Canterra’s canola breeding partner, DL Seeds. The company was attempting to create another variety resistant to existing pathotypes, but lo and behold it turned out it was also resistant to the new strain.

“In some cases in plant breeding there is some luck that does play into it,” he said.

Canterra says CS2000 is well suited to medium to longer season growing zones, resistant to blackleg, medium to tall in height, has great standability and yielded 105 percent of the check variety, Pioneer’s 45H29 canola, in registration trials.

“It’s a very well rounded variety,” said Hansen.

Jurke said growers in the clubroot epicentre surrounding Edmonton who have been growing resistant varieties for a couple of cycles should consider planting CS2000 to switch things up.

However, he stressed that growers planting resistant varieties still need to employ best management practices.

If the disease is established on their land, they need to move to a four-year rotation.

High risk fields should be the last ones producers work on, and farm equipment should be thoroughly sanitized when leaving those fields.

Jurke advised growers in infected areas to control canola volunteers and other weeds in the canola family.

“They will act as disease bridges to carry the pathogen over from one year to another and building up inoculum,” he said.

Growers should employ minimum tillage on infected fields because conventional tillage churns the soil and spreads the disease.

Contact sean.pratt@producer.com

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