Drought-proof canola remains elusive

Modern canola hybrids yield more, are resistant to diseases such as clubroot and blackleg and their pods are less likely to shatter when straight combined. 


However, the specific trait that many canola growers needed this year does not exist: tolerance for heat and drought.


It’s possible, thanks to better genetics, that the latest canola hybrids are more tolerant of 30 C temperatures and dry topsoil than previous varieties. 


That’s difficult to know for certain, said Justine Cornelsen, an agronomist with the Canola Council of Canada.


“Right now I think we struggle with a good way to measure that (trait) in varieties,” Cornelsen said. 


“We kind of just do observations. This variety performed really well in a dry year, compared to the rest. But you’re going to have other factors at play. Was it because of the heat or the moisture (that) was causing this one to out-perform the others? We don’t really know.”


It’s been smoking hot and dry in many regions of Western Canada this summer. Regina recorded only 1.8 mm of rain in July and temperatures regularly topped 30 C.


Hundreds of canola crops have suffered in the scorching conditions. 


Heat blast and lack of moisture will cut into yields.


“I think I kind of have a rough handle on what it will look like, and that is that canola is probably the hardest hit of the crops,” Saskatchewan Agriculture Minister Lyle Stewart said last month. 


“It’s surprising it’s as good as it is, but I think it’s maybe half a crop.”


ADVERTISMENT

Blaine Woychesin, crop manager for canola with Bayer CropScience, said hybrid canola is likely more tolerant of heat stress and drought than the old, open-pollinated varieties.


However, Bayer doesn’t have data showing that one particular hybrid has more heat and drought tolerance than others. 


“Ours would all be very similar…. Your biggest difference might be a early maturing hybrid versus a longer maturity hybrid,” he said. 


“If you have an early maturing hybrid and it’s done flowering (earlier) before the drought, you might be better (off) than a long-season or mid-maturity one.”


Data comparing the drought and heat tolerance of canola hybrids doesn’t exist because it’s a hard thing to test for in the field. 


As well, it’s harder to point to drought tolerance genetics as the reason for better yield because the interaction with soil conditions and the microclimate within the canola canopy is complex.


“The environment and the conditions you would have to have to test that would have to be ideal between the different varieties … to see that A is doing better than C,” said Anastasia Kubinec, manager of crop industry development with Manitoba Agriculture.


Kubinec said all plants have the ability to self-cool.


If it can access enough moisture, the crop can stay cooler than the outside temperature.


As a result, growers can make agronomic decisions, such as seeding rate and target plant populations, which may help canola stay cooler during drought or periods of extreme heat.


ADVERTISMENT

“That’s where we get into … better canopy closure, better conditions for that actual growth and development … so the plant can self-cool,” she said. 


“Genetics takes you so far. Then, it’s how that crop is working as a crop and combatting some of those stresses.”


It would be great to have drought tolerant canola because nearly every year there’s a region of the Prairies that suffers through extreme heat or lack of moisture, Woychesin said. 


However, getting such a trait to market might be challenging.


“There are ways we can look at it … but a genetically modified route would probably be a way you’d be looking for it,” he said. 


“That means as far as regulating it, to get it registered, would be very difficult in the (regulatory) environment we have today.”


Kubinec said drought and heat are the dominant concerns for canola growers this year, but recent history shows that other stressers cause more yield loss.


“I think there (are) much bigger issues that canola seed developers are dealing with, like disease tolerance,” she said. 


“If you look at a 10-year span, we’re probably losing most of our canola yield to disease. It’s not to heat stress…. Blackleg and clubroot are taking more of our yield than I would say heat is.”


  • Regina recorded some of its hottest weather on record this July, according to data recorded by Environment Canada’s weather station:

  • The city had 11 days with daily highs above 30 C.

  • The average daily high for July 2017 was 29.2 C.

  • The 30-year average for July (1981-2011) is 25.8 C.


ADVERTISMENT