The following item is making the news and is given here with a bouyant preface from bio-booster Dr Roger Morton. However, here's the mystery. "Superweeds", in terms of anything that goes out on this list, has always meant disruption of agricultural practice in following years (not necessarily - as in the paper below - long term from a single source) by (multi) herbicide-resistant volunteers, or the potential for herbicide resistance passing to related established weed populations. This paper doesn't address these problems which are happening now (see item 2). A case of weedy weeds or weedy spin?
1. GM plants make weedy weeds
2. 'Superweeds' invade farm fields
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1. GM plants make weedy weeds
originated Morton (under an alias!):
From The Journal Nature comes evidence from a long term study by ecologists on the effects of GM on the weedyness of crops. http://www.nature.com/nsu/010208/010208-9.html
The data reported is from a 10 year study and shows that GM crops do not increase the weedyness of plants.
The authors of the paper note "The concept that GM is intrinsically harmful will have to change,"
So one of the claims of the dangers of GM crops proves to be false. What were the other problems with GM crops?
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biotechnology: GM plants make weedy weeds
JOHN WHITFIELD
A ten-year survey of genetically modified (GM) crops has found that they do not survive well in the wild, and are no more likely to invade other habitats than their unmodified counterparts. The study will help to allay fears that GM plants will be super-weeds, either in their own right or by breeding with unmodified plants.1
"Problem plants have attributes that are totally different from crop plants," says Michael Crawley, an ecologist at Imperial College, London, and the leader of the team that conducted the experiment. "No matter what you do to an oilseed rape or wheat plant, it won't become a problem."
In 1990, Crawley's team planted experimental plots of all the GM crop plants available: maize, sugar beet and oilseed rape varieties that had been made resistant to pesticides, and two varieties of potato modified to be insect-resistant. The researchers grew modified and unmodified crops alongside one another at 12 sites in the United Kingdom.
The plants did not become self-seeding, self-sustaining populations, nor did they spread onto neighbouring unplanted areas. GM and non-GM plants both did equally badly - within four years all plots of maize, beet and rape had died out. Only one plot of potatoes lasted the full decade, and all the survivors are unmodified.
"Approval of GM crops is based on the assumption that crop plants don't survive well without the attentions of farmers," says John Beringer, a microbiologist at the University of Bristol, UK, and former chairman of the UK government's Advisory Committee on Releases to the Environment. "It's nice to see that these expectations have been met."
As for the possibility that GM traits might spread via hybrids, this is a "non-problem" says Crawley. "Gene flow out of crops is irrelevant if the hybrid isn't more competitive than it otherwise would have been," he says.
But the researchers caution that plants genetically modified in the future for traits such as drought tolerance or pest resistance could be better at surviving on their own, and will need to be tested as they are developed. "Our results do not mean that other genetic modifications could not increase weediness," they write.
Beringer concurs that it is the trait that is introduced that matters, and not the fact of modification itself. "The concept that GM is intrinsically harmful will have to change," he says.
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Crawley, M. J., Brown, S. L., Hails, R. S., Kohn, D. D. & Rees, M. Transgenic crops in natural habitats. Nature 409, 682ñ683 (2001).
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2. 'Superweeds' invade farm fields; Canola plants are almost pesticide-proof, experts say
by journalist Tom Spears; 06/02/01
The Ottawa Citizen, '
Genetically modified "superweeds" have invaded Canadian farms - canola plants engineered to help farmers that instead escaped and cross-bred with each other to form plants stronger than their parents.
Most pesticides can't kill these canola superweeds, which are sprouting up in wheat fields and other areas where farmers don't want them, Canada's expert panel on biotechnology says.
Three types of canola, each engineered with genes to resist one type of weedkiller, have merged into new varieties resistant to many pesticides. Instead of helping farmers avoid weeds, the canola itself has become the weed.
The superweed-canola is especially bad in the Prairies, where canola is a multibillion-dollar crop, says a report released yesterday from the Royal Society of Canada's biotech experts.
The biotech industry has been "naive" in thinking that good farming methods alone will hold superweeds at bay, the report says.
And the panel warns that as the next generation of genetically engineered crops becomes more complex, it will be tougher to head off the superweeds of the future.
Canola "is the classic example" of a superweed, said Brian Ellis, a co-chair of the panel and molecular biologist from the University of British Columbia.
Canola varieties such as Liberty Link and Roundup Ready were engineered to use with a pesticide [sic] (such as Roundup). The idea was that a farmer would plant canola resistant to Roundup, then spray the field with Roundup.
Everything except the canola would die.
Where canola is nearly pesticide-proof, it can crowd out other plants - crops and weeds - in farm fields.
But its resistance to pesticides doesn't help its survival in the wild, where there are no pesticides.
"The next generation ... is crops that come along carrying genes thatmake them more frost-tolerant or drought-tolerant. They have an advantage over their wild cousins," Mr. Ellis said.
That means they will have a bioengineered advantage in taking over farm fields and in moving through wild areas.
"Herbicide-resistant volunteer canola planta aare beginning to develop into a major problem" in the Prairies, the panel's report says. (Volunteer plants are those that seed themselves.)
Canola has been farmed for only a few generations and so it still has some wild tendencies - such as dropping its seeds before a farmer can harvest them. This plants seeds for next year.
And plants, the report says, "can be quite promiscuous." Canola plants will breed with any other canola they meet, creating the phenomenon of "gene stacking," or accumulating all the genes originally built into different strains by different laboratories.
This forces farmers to retreat to "broad-spectrum" pesticides - chemicals that kill just about anything, such as 2,4-D. These are chemicals that farmers were trying to get away from in the first place.
"The point is, technology is still driving agricultural production along a chemical-dependence route. And I think that's something the government has to take a very serious look at," Mr. Ellis said.
Biotech industry reps told the expert panel that good farming will stop superweeds from evolving.
"This perspective may be unduly naive," the report says. "In the real world, human error and expediency may often compromise guidelines for the growing of such crops."