If wheat tolerant of the herbicide Roundup is introduced, it will generate unique issues as well as those that arose with the advent of herbicide-tolerant canola.
The controversy over genetically modified, herbicide-tolerant wheat centres around whether it should be approved for registration, since many buyers of Canadian wheat say they don’t want it.
But there is another issue. Does herbicide-tolerant wheat provide agronomic benefits to farmers?
Crop scientists have conflicting opinions about whether the new wheat will help solve weed problems or create new ones.
Read Also
Canadian Food Inspection Agency extends chronic wasting disease control program consultation deadline
Date extended for consultation period of changes to CWD program
But those developing the new wheat say it will give users several benefits, including the ability to seed earlier and to control weeds in a more environmentally friendly manner.
Concerns about creating new herbicide resistance in weeds are all too real for Martin Entz.
The University of Manitoba plant researcher has worked in Australia and saw the effect of multiple herbicide-resistant rye grass on farms there.
“Resistant rye grass crippled cereal production in some areas,” said Entz.
He is an advocate of a systems approach, using crop rotations, forages and another management strategies to control weeds and not relying totally on herbicides. He is not a fan of any herbicide-tolerant wheat system.
“We’ve already done it with canola and to do it with two crops now, I think is really going to take options away from farmers in the long term,” he said.
“I think going to these simple systems where all the crops are resistant to the same herbicide is nuts, and farmers will end up taking all the risks connected with that.”
Entz has four concerns: the effect a modified wheat will have on markets; the potential of the herbicide tolerant gene in the wheat to cross to grass weeds; the trouble zero-till farmers may face with new wheat volunteers; and reduced diversity in farming with more reliance on costly chemical solutions.
“We already have a good production system for cereals and the potential to harm what we have is greater than the good a (genetically modified) wheat will bring.”
Entz noted that although wheat is self-pollinating, it can breed with related plants.
“Wheat can cross with weeds. Jointed goatgrass in Montana can cross with wheat. It does. And that is a weed in southern Alberta.
“The last thing we want to do is start introducing glyphosate-resistant genes into a weed.”
He said zero-till farmers rely heavily on pre- and post-crop applications of inexpensive glyphosate to replace tillage. But glyphosate won’t control volunteer Roundup wheat.
“As soon as we have (glyphosate-tolerant) crop weeds, volunteers, that are now going to appear in these zero-till systems, the question arises, how do you control these weeds?”
He said many zero-till farmers already use herbicide-tolerant canola systems other than Roundup Ready just because they want to preserve the effectiveness of glyphosate for burnoffs.
Don Kelsey, a minimum-till farmer from Choiceland, Sask., and past-president of the Saskatchewan Soil Conservation Association, said he would not use herbicide-tolerant wheat unless the problem of volunteers is solved.
“It would totally change the perspective of farmers in minimum and no-till in using the system.”
Kelsey said the solution might be a new, low cost chemical that controls volunteer wheat like inexpensive 2, 4-D controls canola volunteers.
“I think there probably will be one, but if there is no other chemical, then you’d have to take a look at how to control wheat volunteers and that would mean you’d have to go into the Poasts, Selects or a burnoff with a Liberty type product.
“Those are much more expensive than using Roundup or any of the other glyphosate products.”
A research scientist with Monsanto, the company developing Roundup Ready wheat, says the crop will introduce new management options that will allow fewer applications of the chemical and reduced application
rates.
Curtis Remple said zero-till producers who fear building up resistant weed populations may be able to skip pre-seeding burnoff because of improved in-crop weed control.
“There may be opportunities to spray once rather than twice,” he said.
Eliminating pre-seeding burnoff would also allow earlier seeding, he said. In drier regions of the Prairies, this will meet farmers’ desire to seed into better soil moisture.
Earlier starts for wheat might also improve protein content and make the wheat less susceptible to pests such as wheat midge, said the company. It could help with uniform kernel size, which would also encourage consistent protein.
Wider window
The Roundup Ready crop would have a wider application window than many other crops. The risk of setting the crop back due to herbicide damage is negligible because of its genetic tolerance.
Plants that develop early also canopy faster and this controls many broadleaf weeds that germinate later in the season, say agrologists.
Monsanto said if producers resist the urge to use glyphosate continuously for all weed control and vary the timing of the herbicide applications from year to year, they can reduce some perennial weed problems such as dandelions that have become the bane of many zero-till producers.
As for outcrossing, Monsanto won’t release a Roundup Ready wheat with the potential to outcross with other cereals, Remple said.
“There are a lot of issues that we still need to deal with in the development of the product and it wouldn’t be in our best interest to proceed unless we have planned for them.”
Trish Jordan, manager of public and industry affairs for Monsanto Canada Inc., said a large part of the company’s success is due to the popularity of its glyphosate. It would damage the company to do anything that would make the flagship product less effective.
“There is nothing in this for Monsanto to weaken Roundup in any way. If we lost Roundup, it would not be very good,” Jordan said.
She said Roundup Ready wheat would probably not be appropriate for every situation, noting the concerns of zero-till farmers.
The company has set four requirements before it will put Roundup Ready wheat up for registration: approval from the federal government of the grain’s safety in food and feed; a sound and workable segregation system; a guaranteed buyer for the grain from the crop; and an agronomic package that will deliver proven benefits to farmers.
