Claims of GM-field ‘superweed’ are dismissed
* 15:08 26 July 2005
* NewScientist.com news service
* Rowan Hooper
A herbicide-resistant weed has been found in a field used for the UK’s farm-scale evaluations of genetically-modified crops but – despite the claims of several media reports – it is no GM “superweed”, say scientists.
Researchers at the Centre for Ecology and Hydrology in Dorset, UK, tested the herbicide glufosinate ammonium on plants in fields previously sowed with oilseed rape modified to carry a gene conferring resistance to the herbicide. But a single charlock plant carried on growing happily, raising fears that the gene for herbicide resistance had crossed over to the charlock and created a herbicide-resistant strain. But this is not proof that gene transfer has taken place, says Les Firbank, head of land use systems at the CEH.
“And even if it did occur, it’s not a superweed,” stresses Firbank, “because there’s no sign it can produce viable seeds.”
Gene transfer has been shown in the lab to be possible between GM oil seed rape – Brassica napus – and a closely related species, field mustard – Brassica rapa. But there is not yet proof that it occurred between oilseed rape and the more distantly related charlock, Sinapis arvensis.
Natural resistance
“There is no superweed and there never has been,” echoes Brian Johnson, ecological geneticist at English Nature, the nature advisers to the British government. “It’s more likely that herbicide resistance in charlock has evolved naturally.”
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http://www.newscientist.com/article.ns?id=dn7729