Fighting a lost cause

九月 29, 2000

Alan McHughen argues that ecologists' recent victory against GM crops is hollow because the war has already been lost

The acquittal last week of Lord Melchett and the ecosaviours (or ecoterrorists, depending on your perspective), who in July last year attacked a field of genetically modified maize in Norfolk, has incited vigorous discussion on both sides in the legal, political, scientific and farming communities. But often overlooked is the question of why field tests are conducted in the first place.

Ordinarily, a new maize (or other crop) strain needs to be tested in field trials for agronomic performance. Farmers decide which variety to grow based on expected performance. Data need to be accumulated on such factors as seed yield, disease resistance, standability (if the plants grow too tall in a given environment, they can fall over and break at the stems or at least make harvesting difficult) and the nutritional quality of the final product. A variety that performs well in these categories is more likely to become popular with farmers and therefore be a commercial success.

But genetically modified maize is not an ordinary new variety. It is not a result of traditional cross breeding, where genes from different varieties of the same species are combined to create a novel combination of genes. It is instead a result of recombinant DNA, molecular genetic crossing in which genes from almost any species can be combined to create a desired product, such as insulin, vitamin C or long shelf-life tomatoes.

The small-scale field trials Lord Melchett and company oppose are conducted to assess the environmental effects of GM crops released for commercial farming because of concern that new combinations of genes might be harmful to the environment. If the results show concern is justified, the offending strain can be refused further environmental release or amended to rectify the hazard. If the results fail to provide evidence for concern, the tests may be expanded incrementally over several years as confidence builds in the satisfactory performance, agronomically and environmentally, of the new strain. Even though the small-scale GM crop trials are designed to determine the degree of real threat (if any) to the environment, Lord Melchett justifies vigilante action because of the chance nasty genes might escape from the test site to devastate the environment.

He is too late. Genes from the GM maize are already in the environment. It is very likely that at planting time at least some seeds spilled during transport and equipment preparation en route to or nearby the test site. If the rogue GM maize really was as aggressive as Lord Melchett and his followers fear, the aberrant seeds would have sprouted, established a small population and made themselves evident (a clump of maize plants growing along a roadside is hard to hide). There are no reports that such an invasion has occurred. It has not occurred in America either, where approved GM crops occupy 40 million hectares each year, nor have GM plants been reported to have damaged the environment there.

This brings us to another mechanism by which GM genes were earlier introduced into the UK environment. GM pollen blows around freely in the US, Canada, Argentina, China and other countries where GM plants are allowed to grow and mature. Pollen sticks to the clothing of international travellers arriving at Heathrow and other ports of entry, but customs officers do not ask incoming visitors about the GM pollen content of their clothing. The suspect pollen and even the occasional GM seed also make their way into other farm products, including non-GM commodities shipped from overseas.

Crop trials are useful for a number of reasons - to provide agronomic performance data or to test how an imported variety responds to local insects (one of the goals of the Norfolk trial). Without such field trials, local farmers cannot make informed decisions about which crops to grow, and scientists cannot acquire accurate information on which to recommend rational environmental policy.

Lord Melchett, having won his battle in court, is free to continue his campaign to keep GM genes out of Britain. But he lost the war before the seeds were even sown.

Alan McHughen is professor and senior research scientist, University of Saskatchewan, Canada.

* Are campaigners against GM field trials fighting a lost cause? Email us at soapbox@thes.co.uk. Research, pages 36-37

请先注册再继续

为何要注册?

  • 注册是免费的,而且十分便捷
  • 注册成功后,您每月可免费阅读3篇文章
  • 订阅我们的邮件
注册
Please 登录 or 注册 to read this article.