It was a great day for wheat growers when breeders first transferred the Sm1 gene from varieties of soft red winter wheat into spring wheat. Commercial midge-tolerant spring wheat varieties launched in 2010. But, as they state on the Midge Tolerant Wheat website (midgetolerantwheat.ca), “there is no Plan B.”
To keep wheat midge populations from adapting to the Sm1 gene, the industry developed the idea of planting a refuge within every midge-tolerant crop. Midge-tolerant wheat seed is sold as a blend with a non-midge-tolerant variety that makes up 10 per cent of each seed lot.
The soft white surprise
In 2015, Agriculture and Agri-Food Canada biotechnologist Curt McCartney started wondering about natural midge tolerance in soft white wheat. He began evaluating dissected plant heads. Curt Pozniak and Krystaleee Wiebe at the Crop Development Centre at the University of Saskatchewan were working on a similar question.
Together, these researchers have found that the Sm1 gene occurs naturally in several varieties of soft white wheat. These varieties are: AAC Awesome, AAC Indus, and Sadash. AAC paramount may have the Sm1 gene; confirmation is underway.
The only soft white wheat variety that definitely doesn’t have the Sm1 gene is AC Andrew.
What does this mean? Planting soft white wheat crops that contain the Sm1 gene gives midge populations a chance to adapt. Farmers planting AAC Awesome, AAC Indus and Sadash have been unknowingly putting the usefulness of the Sm1 gene at risk.
What’s the solution? Todd Hyra, business manager for SeCan, says, “my advice to everyone, whether it be a seedgrower or a farmer, is, if they can get AC Andrew and remediate those products that are known now, do it. But I recognize it’s April. There is not going to be enough time, there is not enough seed. This is going to be a several-year process.”
By “remediate,” Hyra is asking farmers to voluntarily add a refuge of AC Andrew to their soft white wheat seed for spring 2017. This would mean adding a bushel of AC Andrew to every nine bushels of Sadash, AAC Awesome or AAC Indus.
Soft white wheat is only a segment of Prairie wheat acres. “We’re fortunate that we’re not dealing with five million acres of wheat,” Hyra says. In 2016, the Canadian Grain Commission reports, 12.4 million acres of wheat were insured in Western Canada. Of these, only 451,571 acres were soft white wheat. And, Hyra says, “half of this wheat is grown in a low midge pressure area. It’s new to Saskatchewan, and that’s the reason it’s important to get to remediation as quickly as we can.”
Deregulating Sadash to get it out of the system is one option. However, Hyra says, “the industry will be best served to have that product in the marketplace.” And, he says, “deregulation would take three years.” Hyra hopes Sadash seed can be remediated more quickly than that.
It’s important that soft white wheat growers co-operate. “The trait is out there for the benefit of wheat growers,“ Hyra says. “We want to preserve it because there’s no other options. That’s why we’ve taken this path of appealing to farmers to add the refuge and remediate as soon as they get a chance.”