Herbicide-resistant Genes Found to Persist in Weeds

By Paul Hanley
The StarPhoenix – Canada
February 19, 2008

It’s not supposed to happen, but it does. Genetically modified canola plants have been found to interbreed with a weed, producing a hybrid wild mustard that is resistant to the herbicide glyphosate (Roundup).

Significantly, these new hybrid weeds are persistent.

Millions are spent on propaganda to calm the nerves of irrational consumers and other overwrought folks worried about the environment, those who fear there is something potentially dangerous about genetic engineering. The main thrust of the campaign is to offer calm and reasoned responses from scientists meant to allay any and all concerns by establishing the “fact” that everything done in the name of biotechnology is perfectly safe. First the propagandists said that genetically engineered plants wouldn’t cross with weeds. When they did, they said the new hybrids wouldn’t persist. They are unstable plants that die out after a year or two, so no need to worry. Now, new research from Agriculture and Agri-Food Canada scientists provides the first report of persistence and apparent introgression (stable incorporation of genes from one gene pool into another). The researchers found the herbicide resistance gene from Brassica napus moved into the gene pool of its weedy relative, Brassica rapa, under normal commercial field conditions. Persistence of the HR trait occurred during a six-year period. Contrary to the propaganda from the biotechnology industry, the scientific community is not entirely at ease with genetic engineering, and for good reason. Given that transgenic canola is grown over millions of acres across Canada and around the world, it is highly likely that herbicide-resistance genes have escaped to weeds in multiple locations. This is of great concern to organizations like the Union of Concerned Scientists (UCS), since it means the emergence of herbicide-resistant weeds could be widespread.

The UCS believes the escape of transgenes into the wild is common. They point out, for example, that the U.S. Department of Agriculture (USDA) has recently fined the Scotts company with the maximum penalty of $500,000 for allowing an experimental turf grass for golf courses to become established in the wild in the U.S. Scotts’ negligence allowed creeping bentgrass, which was genetically engineered to tolerate Roundup, to escape from field trials in Oregon and interbreed with wild relatives. This is the company’s second offence, reports the UCS. Scotts was also fined in 2004 for not notifying the USDA on two occasions that the wind had blown seeds out of its test plots. The company agreed at that time to take additional steps to control the escaped bentgrass, but apparently did not succeed. The transfer and persistence of herbicide-resistant genes in weedy species — and the potential costs to farmers, other landowners, and the environment — is one of the major concerns of the UCS about growing these crops. The organization of scientists is not opposed to biotechnology, however they do oppose the sometimes cavalier attitude with which this new technology is deployed. They believe there is insufficient oversight by regulatory bodies to ensure safety, a concern that is confirmed by a growing number of reports of genes escaped into the wild or unapproved transgenic grains entering the food supply.

The UCS among others hold that the scientific evidence available to date, while generally encouraging, does not support the conclusion that genetically modified crops are intrinsically safe for health or the environment. They say the next generation of products — crops engineered to produce drugs and industrial chemicals or to alter regulatory and metabolic pathways — offer far more numerous traits and appear to be more obviously dangerous than the current slate of herbicide-tolerant and insect-resistant crops. “It would be a serious misstep to overread the positive early experience with Bt and herbicide-tolerant crops and conclude that the weak regulation currently in place will suffice to control the risks of these and other new crops,” says the union. The UCS argues that the regulatory regime must become more stringent as new transgenic plants and animals start to enter the environment in the future.