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Midge-tolerant wheat performs well

Midge-tolerant wheat makes the tiny insect sick, literally, and farmers’ bottom lines a lot healthier.

November 21, 2011  By Donna Fleury

Midge-tolerant wheat makes the tiny insect sick, literally, and farmers’ bottom lines a lot healthier. The first midge-tolerant wheat varieties were commercially available to farmers in Western Canada in 2010. A third resistant variety was added to the list in 2011, and more are expected to be available in 2012 and beyond. Reports from growers so far indicate that the varieties are meeting or exceeding expectations, and overall they are pretty pleased with the results.

Clayton Gellner is pleased with the performance of AC Unity VB. Photo courtesy of Clayton Gellner.


“In terms of prevalence of wheat midge, our impression is there was a fair bit around in 2011, particularly in areas that got planted on time,” says Dr. Stephen Fox, research scientist with Agriculture and Agri-Food Canada’s (AAFC) Cereal Research Centre in Winnipeg, Manitoba. “We did a lot of work in the Saskatoon area this year, and there was quite a bit of midge in that area. However, around Winnipeg seeding was quite late due to wet spring conditions, so most of the crops flowered after the midge flights, allowing the wheat crop to escape damage. Trying to predict where midge problems will be is difficult. In most areas where wheat is grown in Western Canada there is probably wheat midge around; the question is whether or not the levels are high enough to be of concern.” 


Overall, the midge-tolerant varieties commercially available are performing well, and in some cases above expectations. “These new varieties have had a pretty good start, with the recent CWB variety survey showing AC Unity VB as the number 3 variety with 6.6 percent of total area for all CWRS wheat varieties and AC Goodeve VB at number 10 with three percent of total Prairie area,” explains Fox.

“Both these varieties were available in 2010 and 2011, and AC Fieldstar VB became commercially available in 2011 with 0.3 percent of the total Prairie area.” A few others including Shaw VB and Vesper VB are in the pipeline for 2012 and 2013.

AC Unity VB and AC Fieldstar VB
SeCan launched AC Unity VB in 2010 and AC Fieldstar VB in 2011. “Although we are still gathering information and plan for more in-depth survey work over the coming winter with our customers, the initial feedback on variety performance is very positive,” says Todd Hyra, business manager, Western Canada, in Winnipeg. “This is the second year in a row that Unity seems to be doing exactly what we expected or maybe even more than we hoped for. Comments coming back from members are ‘best wheat crop ever,’ and lots of positive comments on both varieties.”

Elaine Bellamy did a lot of research and spoke with seed companies and growers before deciding to grow AC Goodeve VB. Photo courtesy of Will Farms Ltd.


In a 2010 survey, 86 percent of midge-tolerant-wheat customers said they were happy with the results and planned to grow midge-tolerant wheat varieties again in 2011. Hyra notes they had a great start in 2010 and in 2011 growers did grow midge-tolerant varieties as planned, with the supply of Unity practically sold out. “It has been a lot of work to get this new technology out and providing the explanation around the required stewardship agreement for all midge-tolerant varieties,” explains Hyra. “However, growers went ahead with the new technology, and we received several unsolicited calls from growers raving about the experience, the fact the new varieties yielded more, had less damage, less dockage and graded much better. Those kinds of calls makes it worth the effort to get these new varieties out into the marketplace.”

SeCan will have a third variety commercially available for 2012, AC Shaw VB. The co-op data has shown a five percent bump in yield of Shaw over Unity across provincial data, and Shaw was the top of the 2010 trials. “Unity is one of the highest yielding wheat varieties in the marketplace, so to be able to add another five percent yield is huge. Based on what we are hearing from our members who have been growing this variety for the past two years, this five percent increase is real.” Orders are already coming in for Shaw for next year.

“These varieties are available across Western Canada, although Saskatchewan has had the biggest uptake because of the history of midge pressure and damage,” says Hyra. “However, growers may have been impacted by midge and not really noticed in the past, so switching to midge-tolerant varieties can protect yields. There is no agronomic penalty to growing these new midge-tolerant varieties, it’s just pure protection built in and growers in fringe areas should consider growing it as well.” Clayton Gellner of Gellner Seeds near Southey, Saskatchewan, has grown Unity for the third year and is very pleased with the results.

“Three years ago we grew some plots of Unity, which had double the yield compared to Lillian,” says Gellner. “In 2010 and 2011 we switched completely over to Unity on all of our wheat acres and had exceptional yields in both years. In 2010, conditions were poorer, but Unity still graded a #2 while most other varieties were downgraded more than that. My dad says it is almost like combining barley and the yields we are getting with Unity for this area honestly make combining wheat fun.”

With midge-tolerant wheat varieties, growers can achieve high yields without spraying for midge, and in the three years Gellner has been growing Unity he has not had any samples downgraded or rejected for midge damage. “In addition, we didn’t have any sawfly problems this year, and because Unity is a semi-solid stem I think that helps a bit. Although Unity is a tall-strawed variety that is rated with potential for lodging, we haven’t had an issue with Unity lodging at all. Even in the first year, Lillian lodged quite a bit but the Unity crop stayed standing.”

Gellner notes that many growers in his area have tried Unity and are very pleased with the exceptional yields, ranging from 40 to 70 bushels per acre in the Southey area, and to date he has not heard any negative comments. “I just heard from one grower who was very pleased and surprised that his Unity crop yielded 70 bu/ac,” says Gellner. “We’re also noticing that Unity has provided consistently high yields across the region, unlike some others where yield has been quite variable.”

AC Goodeve VB
Alliance Seed Corporation made AC Goodeve VB commercially available in 2010, and so far growers are very pleased with the results. “I think all of the wheat-midge-tolerant lines have been pretty good, which is a function of the good breeding programs at AAFC and University of Saskatchewan, and that there was likely more damage before that growers hadn’t noticed,” says Dale Alderson, general manager. “Farmers I’ve talked to are very pleased with the results and believe these varieties perform very well.”

Alderson adds that using midge-tolerant wheat varieties is a good insurance strategy for growers to reduce their risk. “Midge-tolerant wheat varieties are a good risk-management tool for farmers and there is no yield penalty or cost premium . . . I think these are here to stay,” says Alderson. “When you look into the variety distribution by area, these varieties are pretty dominant in the wheat midge problem areas, so obviously they are performing well.”

Breeders have developed a range of varieties that include short, strong-strawed, earlier maturity varieties through to taller, later maturing varieties that tend to yield a bit better. “AC Goodeve VB is one of the strongest-strawed varieties and is well suited to shorter season areas, places with delayed seeding, or growers who are aggressive fertilizer users and worried about lodging,” says Alderson. “We expect to see it available for a few more years to come and our stakeholders want to see good wheat-midge-tolerance offerings available for their areas.” 

Elaine Bellamy, CEO of Will Farms Ltd. in Rosebud, Alberta, and a third-generation farmer, crops 10,000 acres every year with about 6000 acres in spring wheat as part of the family farm. Bellamy has grown Goodeve for the past two years and is very pleased with the high yields and high bushel weights. Even though there was lots of straw, all the harvest operators reported threshing was easy.

“Initially, when the midge-tolerant varieties became available, I was a little unsure about the requirement of having to purchase Certified seed every two years,” says Bellamy. However, after doing the math, which shows eliminating the cost of midge spraying is equal to half the cost of the initial seed purchase, that made the cost of the seed acceptable. The high cost is only there in the first switchover, because after that a very few acres planted each year to Certified seed can supply seed for the next year’s crop.”

Bellamy did a lot of research and talked with seed companies and local area seed growers before deciding to grow Goodeve, which is a bit earlier maturing and had the best fit for her farm. “Goodeve has performed very well and my harvest crew really enjoyed combining these high-yielding fields,” says Bellamy. One 950-acre field this fall yielded 80 bu/acre, and  the average for all fields was 65 bushels with high protein. I also grew 300 acres of Fieldstar this year and, although it was very high yielding, it was very hard threshing in comparison to Goodeve, with the combines having to go about a mile [per hour] slower.”

Along with wheat midge, Bellamy notes that leaf diseases are also an increasing concern. She is still evaluating which varieties she will grow next year, but notes that Goodeve reduces another risk and takes another worry out of farming. “There isn’t a surprise at the end of harvest when you get your samples graded,” she says. “I know my crops are protected from midge, but I still go out and check what the midge pressure is every year. Breeders are doing a remarkable job with new variety introductions and because farming is progressive we need to continually look for what fits best every year.”

Continued Breeding and Stewardship Efforts
Researchers are continuing breeding efforts with the current type of orange wheat blossom midge tolerance that relies primarily on the Sm1, an antibiosis resistance gene, which elevates existing organic acids in developing kernels, thus starving the larvae. The adult female lays eggs on midge-tolerant wheat, but the Sm1 gene makes the plants unpalatable to the larvae and they starve to death. “Some of the varieties that carry the Sm1 gene express the tolerance differently, which shows up in the amount of seed damage,” says Dr. Stephen Fox, research scientist with Agriculture and Agri-Food Canada’s (AAFC) Cereal Research Centre in Winnipeg, Manitoba. “The larvae still chew on the developing kernels a bit before they discover they don’t like it, but the factors that deter the larvae are expressed more strongly in some varieties compared to others, leading to less damage in some varieties than in others. One of the new varieties soon to be released is Shaw, which seems to have a stronger expression of tolerance with damaged kernels being hard to find. If we can lower the amount of midge damage to ‘hard to find’, that’s the kind of tolerance farmers like.”

Another type of tolerance that Fox and his team are exploring focuses on oviposition deterrence. “With oviposition deterrence, the plant has something that puts the adult female midge off a bit so she won’t lay her eggs right away,” explains Fox. “Adult midges don’t have any mouth parts so they can’t eat anything. I like to think of the adult female as a battery: she can use her energy to fly around or to lay eggs. If she flies around for longer before laying eggs, then she won’t be able to lay as many eggs, leading to less larvae and therefore less seed damage.” Varieties such as Waskada have this type of tolerance.

Ultimately, Fox is hoping they will be able to actively combine the oviposition deterrence with the Sm1 gene. “The deterrence trait is more difficult to work with, and we are still learning how to select for it,” says Fox. The new variety Vesper has the combination of Sm1 and the oviposition deterrence trait but this was by chance alone.

Fox adds, they are also trying to mesh midge tolerance with genetic resistance to other key problems into one package: stem rust, leaf rust, fusarium head blight and wheat midge. “We’re getting the pieces together and trying to move midge-tolerant varieties from an AC Barrie level of FHB resistance at best, to having more of a Carberry or Cardale kind of resistance along with midge tolerance. Today, most spring wheat breeding programs have those kinds of breeding targets.”

Researchers are also working with industry and seed growers on the midge tolerance stewardship component. Currently, growers must buy Certified seed and sign an agreement that enables them to use farm-saved seed for one year, and then they must purchase Certified seed again to maintain the proper refuge status. “One of our AAFC researchers, Dr. Doug Procunier, is just completing a four-year study that will help industry determine the required frequency that producers must buy Certified seed,” adds Fox. “Once all of the data is analyzed, the results will be used to provide guidance to the seed industry.”

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