Field Trial of Gossypol-Free Cotton Seeds Yields Good Results

Field trials of a genetically modified cotton variety that produces less gossypol in its seeds are verifying previous labs and greenhouse studies indicating that the crop could become an important source of protein for millions of poor people around the world. Gossypol is a toxic compound produced by the cotton plant to ward off insect pests. It has long been a block for cotton farmers trying to make cotton seed available for human or animal consumption. Annual world cottonseed production equals about 44 million metric tons, and studies have shown the seed to be about 22 percent protein.

The transgenic cotton variety was developed by Keerti Rathore and colleagues at the Texas AgriLife Research using RNA interference. Although not yet published in scholarly journals, Rathore said that five generations of the transgenic cotton plants produced in greenhouses and the small test plot in the field this year are showing similar findings. "We have analyzed the plant leaves, flower organs and seeds," Rathore said. "The levels of gossypol and related defense chemicals are similar to that of regular cotton plants in the buds, leaves and flowers. But the seed is still showing the ultra-low levels of gossypol."

Rathore said that he will continue the field trial studies to assure the stability of the gossypol-free cotton variety. He will also test the performance of other lines that he expects have even lower levels of the compound.

The original article is available at http://agnews.tamu.edu/showstory.php?id=1399 Rathore's original paper, describing the development of the gossypol-free cotton variety, is available at http://dx.doi.org/10.1073/pnas.0605389103