Thursday, July 28, 2005

Genetically-modified fears

'GM crops created superweed, say scientists', declared the Guardian, reporting on a study of genetically modified oil-seed rape. Researchers from the Centre for Ecology and Hydrology (CEH), the government research station at Winfrith in Dorset, found that in a field of the GM crops, a charlock plant - a weed distantly related to oil-seed rape - was not affected by herbicide applied to it. Dr Brian Johnson of English Nature told the Guardian that even though the occurrence was likely to be rare, 'You only need one event in several million. As soon as it has taken place the new plant has a huge selective advantage. That plant will multiply rapidly.' The report has prompted calls for further delays on the rollout of GM crops in the UK.

It is a serious problem for farmers if weeds become herbicide-resistant. However, there is little about genetic modification that makes the process more likely than before.

Herbicide-resistant weeds already exist, and are a significant problem in Argentina and Canada. But these weeds were created by natural selection, not GM technology. At present, the charlock plant referred to in this report seems to be a one-off. Seeds taken from the charlock plant could not produce new plants, suggesting that even if such hybrids are occasionally created, they often won't reproduce.

Even if they can reproduce, there is good reason to believe their impact will be small. 'Herbicide-tolerant weeds tend to under-perform compared with wild type, so unless all its competitors have been sprayed out with the same herbicide, it won't thrive', Dr Les Firbank from CEH told BBC News. The researchers found no herbicide-tolerant charlock the following year in the same fields - which seems to contradict talk of a 'huge selective advantage'.

The truth is that genetic modification gives seed producers far greater control over crops, with benefits in terms of output, reduced use of chemicals, and nutritional composition. However, the use of this technology has been held up in the UK by the defensiveness of the British government and its scientific advisers to the complaints of environmental groups who are implacably opposed to GM.

This panicky response has prevented a more balanced discussion of risks versus benefits, seeing the development of GM as work-in-progress with enormous potential. It's time to weed out these scare stories.

spiked: Don't panic