The University of Manitoba plant researcher has worked in Australia and saw the effect of multiple herbicide-resistant rye grass on farms there. 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. 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 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. And that is a weed in southern Alberta. The last thing we want to do is start introducing glyphosate-resistant genes into a weed. But glyphosate won't control volunteer Roundup wheat. It would totally change the perspective of farmers in minimum and no-till in using the system.