First gene-spliced wheat.

In a feat that could boost wheat production worldwide, plant biologists have for the first time permanently transferred a foreign gene into wheat.

The gene makes wheat resistant to the herbicide phosphinothricin -- sold under the trade name Basta -- which normally kills any plant it touches, weed or crop. Plant breeders say the Basta-resistant wheat should enable farmers to spray their fields with the powerful chemical to eradicate weeds without harming their harvest.

Indra K. Vasil at the University of Florida in Gainesville and his colleagues have worked for years to genetically engineer wheat, one of the world's most important food crops. Several times, they inserted a foreign gene into a young wheat plant, but the plant failed to pass the gene on to successive generations, indicating the gene's instability.

Now, in the June BIO/TECHNOLOGY, Vasil and his co-workers report they have engineered a wheat plant that can reliably hand down a new gene to its offspring. The researchers used a .22-caliber "gene gun" to blast the gene for an enzyme that breaks down Basta directly into a clump of wheat cells grown in the laboratory. The immature cells grew into fully developed wheat plants that proved resistant to the herbicide, Vasil's group found. Moreover, when bred with normal wheat plants, the genetically engineered wheat yielded two successive generations of Basta-resistant plants.

The development is a "significant achievement," says Donald N. Duvick, a semiretired plant breeder affiliated with Iowa State University in Ames and formerly vice president for research at Pioneer Hi-Bred in Johnston, Iowa. But Duvick cautions against widespread use of Basta and Basta-resistant wheat. "They shouldn't be used too extensively," he asserts, "because weeds could evolve resistance to the herbicide, too."

Vasil says his group is now attempting to insert genes that would allow wheat plants to fend off devastating viral and fungal infections. Next, he says, they hope to use genetic engineering to boost the nutritive value of the grain.