Superweeds - a problematic complication

For a rapid "at a glance" idea of the consequences of the finding reported here, see Comment by PSRAST

Weeds resistant to herbicides is a great problem to farmers. With traditional farming, such resistance tends to arise in weeds as a result of repeated exposition to herbicides. This may take several generations and grows slowly. Now a new mechanism of rapid development of herbicide resistance has appeared with genetic engineering. I is found in crops developed to withstand one specific herbicide. This resistance makes it possible to spray with enough large doses to exterminate all kinds of weeds the producers say. Nothing will grow on these fields but the crop. However, in practice, this may not be the case.

At the 1998 Annual Meeting of the Ecological Society of America Baltimore two scientists reported that they had discovered new evidence that the genes can spread from crops to weeds (Dr Allison Snow of Ohio state university, USA and the Danish researcher Rikke Bagger Jørgensen at the Risø National Laboratory in Danmark).

They had crossed a herbicide-resistant oilseed rape with a wild relative in the laboratory. According to former studies, such crossing yield plants with low fertility because of fewer flowers and low seed production. This finding has commonly been used by the Biotech companies as a selling argument becuse it would mean that if some gene transfer would occur to weeds, the resultant plants would not be fertile enough to produce significant offspring.

The mistake of former researchers was only to study the first offspring generation. Snow and Jørgensen however followed up several generations. And the results was the worst possible for the Biotech companies:

"By the third generation, the weeds that carried the gene for herbicide resistance looked exactly like normal weeds. The only way to tell them apart was to expose them to herbicide or test their DNA," Dr Snow said at the meeting. The laboratory hybrids had all the aggressiveness of the weed parents with weedkiller-resistance built in.

Oilseed rape belongs to the brassica family. Wild brassica weeds often grow in the same area.Therefore it would be easy for the herbiciede resistance genes to transfer with the pollen. Experiments have demonstrated that GE oilseed rape pollen can reach weeds more than a mile away.

"If farmers spray their crops with the same herbicide every year, the only weeds to survive will be the ones with the transgenes - and then the transgenes will spread even faster," Dr Snow said. "That's why the area of crop transgenes is so controversial."

Comment by PSRAST on the "Superweed" report

This research punctuates the marketing argument of GE crop producers that problematic weeds are not likely to appear even if the herbicide resistance genes would spread to weeds. Their argument. that the offspring has been found to have low fertility, now turns out to be fallacious. It was based on research studying only one generation. But this research demonstrates that already after a few generations, the offspring with herbicide resistance genes becomes as fertile and aggressive as normal weeds. - With the problematic difference that it is effectively resistant to the herbicide.

This result exposes a very common and serious defciency in the argumentation of the GE proponents. It is the scanty evidence on which their arguments are based. The same holds for their claims about the environmental safety of GE crops. It is based on scanty and very incomplete evidence that does not permit any conclusions or predictions about the long term effects of release of GE crops.

This study also exposes the weakness of the argumentation that GE would contribute to sustainable agriculture. In the abscence of knowledge of long term effects, there is no basis at all for such an opinion. This study is just one example of the many possible unexpected complications that may occur, making GE agriculture all but sustainable.

GE agriculture is a large scale experiment with seriously insufficient knowledge of the risks. There is no scientific basis for approving any releases at all. Therefore a moratorium is necessary on the release of GE organisms.