Evidence has emerged that transgenic oilseed rape, used to make canola oil, is interbreeding with related wild species, raising fears that herbicide-tolerance could spread among weeds.
Genetically Engineered Plants Crossbreed With Weeds
In a three-year study, researchers analyzed weed species growing in 28 fields partially sown with transgenic oilseed rape, which was genetically engineered to be resistant to the herbicide Liberty. They identified two plants that seem to possess characteristics of both oilseed rape and charlock, a related weed species, which suggests the two may have hybridized.
One of the two plants, which seemed to possess physical characteristics of both species, was infertile. But the other plant, which more closely resembled the charlock weed, was not only robust and fertile, but also demonstrably resistant to the Liberty herbicide.
"The Real Possibility of Superweeds"
Environmental groups are saying this is evidence that transgenes can escape into the plant community at large, and raises the possibility of fertile, herbicide-resistant weeds with unknown transgenic characteristics. Other scientists argued that the herbicide-resistant charlock could have arisen naturally, but, as a campaign spokesperson for one environmental organization put it, "We're seeing the real possibility of superweeds being created."
The findings are not unexpected: oilseed rape has previously been found to hybridize with wild turnip, and back in 2002 it was known that normal crops could be contaminated by GM varieties, making weeds impossible to control.
Nature July 25, 2005