ALBANY, Calif., Oct. 19--A new tactic to genetically engineer potatoes might open the door to superb new spuds for baking or processing into chips, fries and other tasty potato products.

Scientists with the U.S. Department of Agriculture's Agricultural Research Service and Small Potatoes, Inc., Madison, Wis., have a new cooperative research and development agreement to investigate a gene re-built to improve potatoes. The gene reduces production of unwanted natural compounds in otherwise promising experimental potatoes.

Called glycoalkaloids, these bitter-tasting chemicals make potatoes unmarketable and may cause breeders to abandon work on a promising tuber. "That may happen even if the experimental potatoes boast desirable traits like an appealing color or texture, or resistance to attack by insects or diseases," said William R. Belknap, plant physiologist with the Agricultural Research Service. He is based at the ARS Western Regional Research Center, Albany, Calif.

Under the new agreement, Belknap is providing Small Potatoes with a gene discovered and re-built in his laboratory. In nature, the gene cues the potato plant to make an enzyme critical for production of a key glycoalkaloid. Scientists on Belknap's team, however, re-built the gene into a backwards or "antisense" version.

"Experimental potato plants with the antisense gene inside contain up to 50 percent less glycoalkaloids," said Belknap. ARS is seeking a patent for the antisense gene.

At Small Potatoes, Peter J. Joyce and colleagues will employ techniques developed by the company to move the anti-glycoalkaloid gene into potatoes, then test the tubers for glycoalkaloid levels and other characteristics. Joyce will also use potatoes, provided by ARS, that already possess the new gene.

Potatoes are America's most popular vegetable. The 1996 crop of 25 million tons was worth $2.4 billion to growers.

ARS is the principal research arm of the U.S. Department of the Agriculture.

Scientific Contact: William R. Belknap, plant physiologist, Crop Improvement and Utilization Research Unit, Western Regional Research Center, Agricultural Research Service, USDA, Albany, Calif., (510) 559-6072, fax (510) 559-5777, wrb@pw.usda.gov.