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Originally Posted by jammies
The question would be far better put, "Do weeds evolve to carry the same herbicide-resistance as crops designed or bred to resist those same herbicides?"
Of course, since the answer to that question is both obvious, and can be shown to be true,
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Let's put it even better and be more specific: "Are weeds likely to evolve to carry the same resistance to glyphosate as crops designed or bred to resist glyphosate?
16 years ago the general concensus answer to this question (although there are many documented concerns) would have been "highly unlikely".
Today of course, the answer to that question is both obvious, can be shown to be true and has shown the general concensus of 16 years ago to be wrong.
Quote:
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February 10, 1997 - In Volume 8 of Resistant Pest Management, the biannual newsletter of the Pesticide Research Center at Michigan State University, there were two articles discussing the development and existence of weed populations that are resistant to glyphosate herbicide. Given the interest that Iowa growers have expressed in the use of Roundup Ready soybeans, and the general feeling that there is a low risk of weeds developing resistance to glyphosate, these articles are extremely interesting.
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http://www.weeds.iastate.edu/weednews/roundup.htm
Quote:
Originally Posted by jammies
So, I have a question for you: do you understand that "GM crops" is not a monolithic entity that can have motives and behaviour ascribed to it, and that the current collection of "GM crops" is no more than a tiny sub-group of the almost limitless possibilities of this technology?
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Yes and Yes.
Not directed at you specifically. Just a couple of choice snips from another paper where the author suggests that GRCs are creating superweeds.
Quote:
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Weed populations shifts have occurred in response to the adoption of GRCs. The evolution of resistance to glyphosate is now an accepted fate of recurrent use of glyphosate in GRCs. It is now apparent that there were fewer constraints on the evolution of glyphosate resistance than originally proposed, and resistance to glyphosate has evolved in many species and is widely distributed
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Quote:
The adoption of GRCs does not directly impart selection pressure on theweed community. However, the production systems used in GRCs increase selection pressure on the weed community owing to the predominance of conser-
vation tillage and the limited number of herbicides (glyphosate) used to control weeds. Increased selection pressure increases weed population shifts.
The selection pressure imparted by glyphosate will cause weed shifts attributable to the natural tolerance of a particular species to glyphosate or the evolution of glyphosate resistance within the weed population.
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http://www.ask-force.org/web/Herbizi...hifts-2008.pdf