Following a decade of work, scientists at Washington StateUniversity transferred a gene from split peas to potatoes thatimproves the potato's resistance to a fungal disease calledVerticillium wilt.

"The addition of the resistance capability to the Russet Burbankvariety, which accounts for 70 percent of Washington's potatoproduction, will make a significant contribution throughreduction in nitrogen fertilizer and pesticide use and increasedyields to our nearly $300 million potato industry," saiduniversity extension horticulturist Robert Thornton.

Washington potato growers spend about $23 million annuallyto fumigate their fields to control Verticillium wilt, nematodesand other pests.

Verticillium wilt, a soil-borne disease caused by a fungus, isfound in most temperate regions of the world. In the PacificNorthwest, it affects crops ranging from eggplants to potatoesand ornamentals such as roses.

The disease clogs the vascular systems of host plants, blockingmovement of water. Affected plants eventually turn yellowand die prematurely. In potatoes, the state's fifth-leading crop,the wilt hits as tubers are still developing, stopping growth andreducing yields.

A team of scientists led by Lee Hadwiger, a plant pathologist,transferred pea gene 49 to the Shepody and Russet Burbankpotato varieties. This gene provides improved resistance toVerticillium wilt.

Under field conditions, the gene adds two more weeks of life topotato plants before they succumb to the disease. "Any timethat you can add to the life of the potato after tubers start todevelop, you can potentially increase yield," Hadwiger said.

In field tests last year, Shepody potatoes with the resistancegene produced up to twice the yield of unprotected potatoesexposed to the fungus.

Shepody is an early-maturing variety used to make Frenchfries. It's harvested from mid-July through August, andaccounts for about 10 percent of the state's potato tonnage.

Hadwiger has transferred pea gene 49 to the Russet Burbank aswell, but that research is still early in development, and thereis no field trial data available.

A tri-state variety testing program should begin as soon asenough seed potatoes have been raised. If the variety meetsexpectations, it could be available to growers in three to sixyears.

-- Nancy Garcia Associate Editor

(c) 1997 American Health Consultants. All rights reserved.

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