Because both oilseed rape and its weedy relatives were introduced to the U.S. by settlers from Europe, wild versions of the species often grow side-by-side with the cultivated plant. This isn't a problem for corn, soybeans, potatoes, and tomatoes, none of which have weedy relatives in the U.S. Sunflower and squash plants, on the other hand, are both native born, so they naturally have genetically-compatible weeds growing nearby. That's why genes from cultivated oilseed rape, sunflowers, and squash can escape from crop plants into the weed population.
In fact, previous studies have shown that oilseed rape pollen can reach weeds nearly one 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," said Snow.
As transgenes in the cultivated crop change, traits could accumulate in the weeds. For instance, a weed could develop a resistance to 3 or 4 herbicides as it acquired genes from consecutive generations of crops over many years.
"It's hard to worry about a problem that may take 5 or 10 years to develop," admitted Snow. "We're trying to project what could happen or will happen in the future."
"That's why the area of crop transgenes is so controversial," she continued. "Some people don't even want to think about it, and other people think it's a disaster. I think the truth lies somewhere in-between."
Snow said that she and her colleagues would have to study oilseed rape and Brassica rapa in the field to fully gauge the benefits of herbicide resistance in the weed.
"I don't like to paint this as an emergency, or as a disaster waiting to
happen. I just think it's important to understand what we're doing when we
create trans
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Contact: Allison Snow
Snow.1@osu.edu
(614) 292-8433
Ohio State University
6-Aug-1998