Gene Flow from Transgenic Grass

A new study finds that genes from Roundup Ready creeping bent grass can travel at least 13 miles. The study validates the concerns of many scientists and environmentalists that the genetic alteration of some crops may not be contained and could thus spread widely to other domestic or wild plants.

The genetically engineered grass is being developed by Monsanto and Scotts as a turf plant for golf greens and fairways. Previous studies have found that crop genes flow only about 1,400 feet. The new work reveals the possibility that altered genes can, in fact, spread great distances. In the case of bent grass, there is a concern that herbicide resistance might spread to wild bent grass and other related species.

These results could influence USDA's deliberations over whether to allow the transgenic bent grass to be commercialized. About two months ago, USDA decided to require an environmental impact statement (EIS) on the grass, says Meghan Thomas, spokeswoman for USDA's Animal & Plant Health Inspection Service (APHIS). This is the first time USDA has done an EIS on an engineered crop. It made this unusual decision because bent grass is a perennial crop and therefore harder to control than annual crops such as corn and soybeans, Thomas says.

Creeping bent grass is most commonly used on golf course greens and fairways because it can be cut very short. Currently, there is no way to prevent bluegrass from mixing with the bent grass on greens, and managers must use a variety of herbicides and fungicides that are compatible with the two grasses, says Jim King, Scotts's director of communications. With transgenic bent grass, bluegrass could be eliminated with Roundup, so "far fewer products would be needed to manage the greens," he says.

In the gene-flow study, the researchers placed 138 pots of creeping bent grass at various distances from trial plots of transgenic bent grass, says Lidia S. Watrud, research ecologist at EPA's National Health & Environmental Effects Research Laboratory and lead investigator in the study, published online in Proceedings of the National Academy of Sciences. After potential exposure to pollen from the engineered bent grass, seed heads from the potted plants were collected. The researchers also gathered seed heads from plants of related wild species that were growing naturally in the area. Many of the seedlings grown from the seed heads were resistant to Roundup, and tests showed they contained the gene that confers Roundup resistance, Watrud says.

Earlier this year, the U.S. Forest Service sent comments to APHIS, saying that transgenic bent grass could transfer its herbicide resistance to relatives, creating weeds that would be impossible to control with Roundup, which is widely used in national forests.

Officials at the National Park Service also have concerns. "In the nation's 387 parks, there are many dozens of situations where close relatives of bent grass are present," says Terry Cacek, park service coordinator for integrated pest management. "We are concerned that herbicide-tolerant bent grasses could compete with native vegetation in the backcountry," he says.

King, however, says that bent grass on golf greens is mown so frequently that it would never produce pollen.

But Watrud notes that if the very fine transgenic bent grass seed is planted on golf greens, bent grass will undoubtedly end up in rough areas and near drainage ditches where it would not be managed so carefully.

Robert Hedberg, director of science policy for the Weed Science Society of America, notes that because bent grass and related species have not historically been weed problems in agriculture, engineered bent grass is not likely to present problems.