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Delaware | Yes, the DNA is definitely different in resistant weeds than in the typical population. Just like GMO crops, there is more than 1 genetic change that can cause resistance to a certain herbicide. Some RR crops have a genetic change that causes them to metabolize the glyphosate faster, others have a change that causes glyphosate not to attach to its site of action. Weeds can also have more than 1 way to show resistance.
There was a study done a few years ago that I can't find the link to right now. The researchers studied the DNA of various pigweed species and correctly predicted by their DNA that palmer was likely to show resistance to PPO herbicides. This was confirmed last year.
The interesting thing is that spraying a herbicide does not cause a particular weed to develop resistance to that herbicide. The resistance gene is already present in a tiny fraction of the weed population, and spraying the herbicide just kill all the other weeds. Therefore the resistant ones are the only ones to set seed. The farmer probably won't notice the first year if 1 plant survives, but after a few years of using that herbicide more and more of the population will be resistant ones, and then is when the problem starts.
I think anything we would call resistance is a genetic thing. I remember reading about a grassy weed in one of the rice growing countries that has developed "resistance" to hand weeding. It has developed a population of grass that looks so much like a young rice plant that it's hard to tell the difference. Therefore it doesn't get pulled out. This is also obviously a genetic difference. | |
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herbicide resistant weeds ?
