Will herbicide-resistant transgenic crops create “superweeds”?
This is a real threat where transgenic crops containing a herbicide-resistance gene grow alongside closely related weed species, such as wild mustards in canola or jointed goatgrass in wheat. Gene movement from crop to weed through pollen transfer has been demonstrated for both of these crops. Proposals to reduce the risk of creating transgenic “superweeds” include linking herbicide-resistance genes to other genes which are harmless to the crop but damaging to a weed, such as genes which affect seed dormancy or prevent flowering in the next generation. Thus if a weed did acquire a herbicide-resistance gene from a transgenic crop, its offspring would not survive to spread the herbicide resistance through the weed population.
