[GE] CANOLA CROSSBREEDS CREATE TOUGH WEED PROBLEM
Canola resistant to Roundup herbicide has turned up in a northern Alberta
farm where none was recently planted. On Tony Huethers farm near Sexsmith,
the Roundup-tolerant trait appears to have been transferred through pollen
movement to canola in a neighboring field.
John Huffman, an Alberta Agriculture crop specialist in Grande Prairie said
that has caused Roundup-tolerant canola to appear in the field where none
had been seeded the year before. "It appears that some pollen has flown
across the road and pollinated the canola and the gene has shown up the
following year," said Huffman, who also worked with the departments weed
specialist Linda Hall to check the possibility of cross pollination.
"When John told me I said Thank God, now we can get the concerns out
there," said Hall of Edmonton.
"We've known and predicted this for a long time," she said. Hall said the
viability of pollen diminishes with the distance it travels from the
source. Sunshine and air impair pollen viability.
The article went on to say that in 1997, Huether planted two fields of
canola. On the west side of a county road he planted Quest, a
Roundup-resistant canola and on the east side of the road he planted 20
acres of Innovator, a Liberty-resistant variety. The rest of the 140-acre
field was planted to 45A71, a Smart canola resistant to Pursuit and
Odyssey. All are Argentine types. The two fields are about 30 metres apart.
The fields were harvested at different times, eliminating the possibility
of contamination by combine, said Huffman. This year, in the east field
where the Innovator and 45A71 were grown one year earlier, Huether sprayed
one litre per acre of Roundup on May 13 for a quick weed burnoff. Because
of dry conditions, he didn't seed the field and sprayed another
three-quarters of a litre of Roundup about a month later. "I was seeing
pretty viable canola plants before and was wondering what was happening.
Even before the second application, I was wondering if the Roundup was
doing the job. I sprayed it and it was the same story. They just kept
going," said Huether. When Huffman was called to Huethers farm 10 days
later, he found some canola had survived.
The Roundup had worked except for a large number of healthy blooming canola
plants, said Huffman.
The unexpected Roundup-resistant canola grows thickest near the road, but
is present throughout the 140-acre field, said Huether. Samples have been
taken from the plants, but haven't been tested. "We're pretty sure they're
highly tolerant because he sprayed them twice," Hall said.
Aaron Mitchell, biotechnology manager for Monsanto in Saskatoon, said he
hadn't heard about the field of cross-pollinated canola, but it isn't
There have been studies of cross-pollination between canolas at various
distances in test plots. Mitchell said, "This is the first known example of
cross-pollination in a field situation. We always expected a level of
natural outcross would occur within the species." He doubts whether wind
carried the pollen across the road, noting bees are more likely the cause.
Pollen of Argentine canola tends to be too heavy for wind. Huether said
there are native bees in the area, and the closest commercial hives are
about 13 kilometres away.
Because seed companies and researchers were aware of possible
cross-pollination, Mitchell said he has promoted the importance of farmers
talking to their neighbors about the varieties of canola they grow. More
than half the canola seeded on the Prairies this year was
herbicide-tolerant and the number of acres is expected to increase as new
varieties reach the market.
"Pollen movement isn't something we totally understand."
RESISTANT CANOLA EXPECTED Oct. 15/98
In a related article, Gary Stringam, a University of Alberta professor who
conducted canola pollination studies when he was with Agriculture Canada in
Saskatoon during the 1970s said it was just a matter of time before
volunteer herbicide-resistant canola from cross-pollination appeared on the
Those studies used recommended pedigreed seed isolation distances. Plots
were established to see how far the pollen would travel from its source.
Researchers found five or six percent out-crossed canola plants up to 400
metres from the original source with Polish canola, said Stringam. Pollen
from Argentine varieties doesn't travel as easily, but outcrosses were
still found 400 metres from the original Argentine plants. Stringam said
the canola can spread up to eight kilometres if there are lots of bees in
the area to carry pollen.
"Pollen movement isn't something we totally understand. There hasn't been a
lot of research. Its true napus or Argentine variety pollen doesn't move
that well on the wind, but that's not to say it doesn't happen. With more
herbicide-tolerant canola being grown on the Prairies. Farmers will need to
be more vigilant about where their canola is grown, what herbicides they
use and what types of canola their neighbors grow."
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