August 6, 2010
Genetically Engineered Invasive Species
Scientists at the University of Arkansas have found populations of wild plants with genes from genetically modified canola in the United States.
Canola can interbreed with 40 different weed species and 25 percent of those weeds can be found in the United States. These findings raise questions about the regulation of herbicide resistant weeds and about how these plants might compete with others in the wild.
"We really don't know what the consequences of the gene escape " said Schafer. "We don't know what these plants are going to do."
The research team used portable strips that test for genetically modified proteins found in canola, proteins that convey herbicide resistance to crop plants. The test strips detect the protein that conveys Roundup resistance and the protein that conveys resistance to Liberty Link, another herbicide used on canola.
"We traveled over 3,000 miles to complete the sampling," Schafer said. Some of the sites had densely packed plants, with 1,000 specimens in a 50-meter space. They spray these roadsides with herbicides, and canola is the only thing still growing.
They found wild canola in about 46 percent of the sites along the highway, either growing on the side of the road or in cracks in the highway. About 83 percent of the weedy canola they tested contained transgenic material, that is, they contained herbicide resistance genes from genetically modified canola. Further, some of the plants contained resistance to both herbicides, a combination of transgenic traits that had not been developed in canola crops.
"That's not commercially available. That has to be happening in the wild," Schafer said. "That leads us to believe that these wild populations have become established populations. Technically, these plants are not supposed to be able to compete in the wild."
Current farming practices may quickly make the problem worse. Each year tens of thousands of acres of canola go un-harvested in the field. As a consequence, an enormous reservoir of seed is created, which can then spread into wild populations.
"Once this happens, it would be difficult to get rid of these weeds using current herbicides," Sagers said. While the problem looms large in North Dakota, Sagers says the message is a global one. The world recently hit a milestone, where more than 50 percent of the earth is covered in crops used for food or forage. Domesticated plants have wild cousins that often are considered weeds, and sometimes these plants can still cross breed, creating a high potential for herbicide and pesticide resistance to show up where it isn't wanted.
"Things can escape from cultivation, and we need to be careful about what we stick into plants," Sagers said.