Research shows: Herbicide tolerance everywhere

By Les Kietke
Manitoba Co-operator
August 1, 2002

Carman - Seed contaminated with herbicide-resistant genes may he a bigger problem than it's being given credit for, according to one University of Manitoba researcher. 

Work being done by Lyle Friesen casts doubts on the entire seed industry.

Friesen collected samples from pedigree seed lots that were to be non-herbicide-resistant canolas.The resulting plots show some samples had enough escapes to provide a crop of herbicide-tolerant canola after they'd been sprayed out.

The most common escape was to Roundup, but he found examples of all herbicide-tolerant products and some plants exhibited tolerance to two types of herbicide

Friesen planted 33 seed lots – none of which were supposed to be herbicide tolerant. Plots were sprayed with Roundup, Liberty and the Smart-trait herbicide.

Only one of the lots did not have any contamination.

“Out of 27 unique CSGA seed lots 14 failed the guidelines of 99.75 purity," said Friesen. “That means 14 lots had more then .25 per cent contamination with herbicide-tolerant seeds."

His research is not intended to find flaws in the Canadian Seed Growers Association inspection system, but rather to see how far afield the contamination has gone.

“This is a problem for direct-seeders or zero-tillers who depend on Roundup to get broad-spectrum, non-selective weed control in the spring," he said.  “Here we find canola volunteers that would be popping through that system and causing problems.”

While the amounts sound minuscule as percentages, when multiplied by common seed rates the problem quickly becomes drastic.

“That means one wrong seed in 400, if a farmer is seeding between 100 and 120 seeds per square yard.  That means you would have a Roundup-resistant plant every couple of square yards," he said. “In a less competitive crop where you can mix products like 2,4-D or MCPA, that becomes a real problem and the volunteers set seed and become a real problem for next year.”

Friesen feels the “genie may be out of the bottle” for canola but warns the industry to be cautious with other herbicide-tolerant plants.

“In terms of Roundup Ready wheat, this work indicates it is very unlikely that we would be able to identity preserve either the commercial grain lots or even our certified seed production system,” he said.

Wheat does not outcross as easily as canola but Friesen says pollen is windborne and can remain viable for as long as an hour.“So with a 30-mile-an-hour wind, where is that pollen going?”