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2-Plants: Canada warns that modified crops can spread further than thought

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-------------------------------- GENET-news --------------------------------

TITLE:  Keep your distance
SOURCE: New Scientist, UK, by Andy Coghlan
DATE:   November 24, 2001

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Keep your distance
Canada warns that modified crops can spread further than thought

STRAY pollen and seed from genetically modified oilseed rape, or canola, is 
now so widespread in Canada that it is difficult to grow conventional or 
organic strains without them being contaminated. That is the stark message 
from Hugh Beckie of the agriculture ministry's Saskatoon Research Center, 
which has been monitoring GM crops since commercial farming began six years 
ago. Canada's experience provides valuable lessons for other parts of the 
world, such as Europe, that don't yet allow commercial production. It 
suggests that GM and non-GM varieties of some crops might have to be kept 
far apart or even grown in separate, designated zones. "If we move towards 
quite a lot of GM growing, there would have to be some sort of zoning," 
says Jeremy Sweet of the National Institute of Agricultural Botany in 
Cambridge.This is already done to prevent contamination of elite 
conventional strains of sugar beet and potatoes, he says.

Beckie, who spoke at the Weeds 2001 conference in Britain last week, 
stresses that much depends on the particular crop. Plants such as wheat and 
soybeans are relatively safe from contamination because they usually 
pollinate themselves. But oilseed rape accepts pollen from neighbours. 
Experiments show that pollen from GM oilseed rape travels much further than 
expected, Beckie says. "Our studies have shown that pollen can travel at 
least 800 metres." That's eight times further than the official Canadian 
"safe" separation of 100 metres for rape grown to supply pedigree seed. And 
it's four times further than the country's 175-metre separation for rape 
grown to supply oil or food.

Only 0.07 per cent of plants at 800 metres were pollinated, but there was a 
long "plateau" between 50 and 400 metres where contamination was about 0.2 
per cent, dangerously close to the accepted 0.25 per cent contamination 
limit for elite seed. Beckie says that there's "a good chance" he will 
recommend extending separation distances. What's more, some GM plants are 
surviving in fields from year to year because they have acquired resistance 
to more than one weedkiller by crossing with other GM strains. Such 
"stacked" resistance is easily managed with other herbicides, but only if 
farmers know the problem exists.

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