Genetically Altered Cotton Is Cheaper And More Earth-Friendly

November 4, 1997

GAINESVILLE – A genetically altered variety of cotton being field tested this season by University of Florida researchers requires less herbicide, which should mean reduced environmental damage, lower production costs for growers and cheaper prices on cotton goods for consumers.

“The cotton genes have been modified so that only one spraying of a common low-toxicity weed killer is necessary,” said Raymond Gallaher, UF Institute of Food and Agricultural Sciences agronomy professor. Moreover, that herbicide, glyphosate, breaks down quickly in the environment.

“That one spraying is enough to kill the weeds but leave the cotton unharmed,” he said. “The beauty of that is that the farmer now has confidence in making an economically profitable crop.”

“The benefit is that it allows reduction and overall use of herbicides,” says Barry Brecke, UF weed science associate professor at the West Florida Research and Education Center in Jay.

Typical herbicide spraying of unaltered cotton requires up to five applications, Gallaher says. The savings from fewer sprayings – to both the environment and the pocketbook – are substantial.

“Two things – cotton and weeds – can’t occupy the same space,” he said. With this genetically altered cotton, farmers can save millions of dollars in crop yield losses due to weed competition. A portion of that savings may be passed on to consumers in lower prices for cotton products, such as clothing, bath towels and linens, he says.

The gene was discovered in 1984 by a scientist working for a commercial chemical company, Gallaher says. The first successful insertion of the gene into an agronomic crop was in soybean in 1989, and the first field testing of soybean took place in 1992.

Since then, efforts have been under way to place this gene in cotton, said Gallaher, one of several land-grant university researchers field testing this altered cotton strain across the Cotton Belt from California to Virginia. A limited amount was also made available for farmers.

The cotton field trials were conducted at Gallaher’s research plots at the University of Florida’s Agronomy Green Acres Field Research Laboratory, 12 miles west of Gainesville.

Gallaher is testing the altered cotton under four different field conditions, including conservation tillage, a system that retains 30 percent or more of the previous crop in the planting area in order to reduce soil erosion. Since conservation tillage disturbs less soil than conventional tillage, it also helps reduce wind and water erosion.

The best results in this season’s field trials were with conservation tillage utilizing strip tillage, which breaks up compacted subsurface soil allowing better root penetration. More developed roots result in better water and nutrient utilization and better developed plants, he says.

In recent years, cotton has become more profitable to grow, Gallaher said. With the fall of the Iron Curtain and the opening of trade with Russia and China, world demand has skyrocketed. Cotton has become one of Florida’s top five agronomic crops.

Florida cotton yields are as good as or better than the national average, said David Wright, UF agronomy professor at the North Florida Research and Education Center in Quincy.

“We are a boll weevil-free state because we participated in the boll weevil eradication program and essentially were able to eliminate that cotton pest,” he said. “The result has been to eliminate as many as 10 additional sprayings per year.”

Moreover, cotton is a good rotation crop for Florida, Wright said. “Florida’s year-round warm climate gives us the advantage of a double cropping system. Cotton fits in nicely with our system of winter crops followed by cotton as a summer crop. It’s an especially good crop to rotate with peanut,” he said.

Next year, the same gene is expected to be available for field testing in corn, Gallaher says.