WINNIPEG – Some bags of conventional certified canola seed contain more
than five percent genetically modified, herbicide tolerant traits, two
University of Manitoba researchers say.
And almost no certified seed they examined in a small study was free of
GM contamination, said weed specialist Rene Van Acker and pesticide
specialist Lyle Friesen.
That means that over time canola growers may develop large seedbeds of
herbicide resistant volunteer canola. And if Roundup Ready wheat was
introduced with today’s certified seed standards, zero-till farmers
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Van Acker and Friesen tested 31 bags of conventional canola and found
only one that did not contain genetic material from GM canola. Over
half the samples had more than 0.25 percent GM herbicide resistant
traits, and some had three to five percent contamination. Over time
that kind of contamination could spread thousands of herbicide
resistant plants across a quarter section, all unknown to the grower.
It would also produce a lot of herbicide tolerant pollen that could
drift to other fields.
Van Acker said he thinks the GM contamination may be coming from plant
breeders who distribute seed to seed growers for commercial
multiplication.
“(Seed growers) may be building a vicious circle on their own farm, but
unaware of it, despite their best efforts,” said Van Acker in an
interview.
Commercial farmers probably don’t realize the conventional canola they
are buying can contain GM material in small amounts, Friesen said.
“I think that most farmers think that if you’re growing a non-Roundup
Ready variety, it will be conventional,” said Friesen.
If this amount of GM canola can be found in certified canola seed, then
some would probably also appear in certified wheat if Roundup Ready
wheat was approved, the researchers said, unless seed regulations were
strengthened.
They projected a potential problem, if glyphosate-tolerant wheat was
widely grown, of volunteer herbicide resistant wheat that could cost
zero-till farmers $400 million per year across the prairies to clean up
with chemicals. The zero-till system relies on glyphosate to control
weeds.
Manitoba Agriculture weed specialist Todd Andrews said the researchers’
projections about potential problems in canola and wheat are possibly
valid, but they need to be backed up by field studies.
“Even though all the numbers looked plausible, because we haven’t seen
that number of cases in the field it’s time to take the theory and do
some field tests.”
Andrews said there were a small number of high-profile cases of Roundup
Ready volunteers becoming a problem in fields in the Red River valley
in 2001, but it was not an epidemic.
In 2002, “I didn’t have a single call about Roundup Ready canola being
a problem.”
Andrews acknowledged that zero-till farmers may be tank-mixing other
herbicides with glyphosate to counter the threat of glyphosate tolerant
volunteer canola.
Monsanto Canada spokesperson Trish Jordan said her company doesn’t
agree with Van Acker’s and Friesen’s conclusions. And it doesn’t
believe their brief study proves much.
“We don’t agree with all of the assumptions and some of the modelling
that has been put into that,” said Jordan.
She also said theoretical models need field testing.
Gene flow in wheat is very rare and unlikely to be a problem, she said.
