News Release

Modified crop breeds toxic hybrid

Reports and Proceedings

New Scientist

CROSSES between genetically modified oilseed rape and a wild relative produce hybrid plants that are as toxic to insects as the original crop. Though it is still unclear how such hybrids would fare in the wild, the finding is likely to be seized on by environmentalists as proof that field trials of GM crops are unsafe.

In lab experiments, Matthew Halfhill at the University of North Carolina in Greensboro and colleagues took oilseed rape (canola) that had been modified to contain the insect resistance gene Bt and crossed it with a related weed, birdseed rape (Brassica rapa). They made 11 crosses using different combinations of plant lines. Five of them produced stable hybrids containing the Bt gene. These expressed the insecticide produced by the gene at levels similar to the GM parent and were highly toxic to insects.

The finding will fuel fears that "superweeds" containing foreign genes making them immune to insect attack might spread rapidly. But no one yet knows how much of an edge insect resistance would give the hybrids compared with their non-GM relatives. "Without doing ecological experiments, your guess is as good as mine," says Brian Johnson, biotechnology adviser to the government conservation agency English Nature.

Some researchers believe that birdseed rape may be restricted more by competition with other plants than by insects. One reason Bt-oilseed rape is not grown commercially, even in countries that allow GM crops, is that insect pests don't have a serious impact on oilseed rape. If insect resistance doesn't confer a significant advantage to birdseed rape either, the Bt gene would be unlikely to spread.

Halfhill's team also showed that similar hybrids can form under field conditions. Crosses between oilseed rape and birdseed rape are well documented, but this is the first evidence that the Bt gene might pass to the hybrid from modified crops. "This demonstrates that hybrids can and will be formed and that they will have insecticidal activity," says Johnson. He says this underlines the importance of investigating the environmental consequences before GM rape is released.

###

Author: James Randerson

New Scientist issue: 30th November 2002

PLEASE MENTION NEW SCIENTIST AS THE SOURCE OF THIS STORY AND, IF PUBLISHING ONLINE, PLEASE CARRY A HYPERLINK TO: http://www.newscientist.com

"These articles are posted on this site to give advance access to other authorised media who may wish to quote extracts as part of fair dealing with this copyrighted material. Full attribution is required, and if publishing online a link to www.newscientist.com is also required. Advance permission is required before any and every reproduction of each article in full - please contact angela.bourton@rbi.co.uk. Please note that all material is copyright of Reed Business Information Limited and we reserve the right to take such action as we consider appropriate to protect such copyright."

US CONTACT - Michelle Soucy, New Scientist Boston Office:
Tel: 617-558-4939 or email michelle.soucy@newscientist.com


Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.