Potato Growers Have New Nematode-Resistant Germplasm

North American potato growers now have new germplasm that thwarts two key pests-- golden and “white” potato-cyst nematodes.

Genetic resistance is crucial to controlling these and other microscopic worms, called plant-parasitic nematodes, that cause an estimated $9 billion in losses to U.S. agriculture each year

Methyl bromide now protects more than 100 crops from nematodes and a variety of other pests and pathogens, but is scheduled to be phased out by January 1, 2005. So developing nematode-resistant germplasm is more important than ever.

The golden nematode, Globodera rostochiensis, can wipe out entire potato crops by feasting on the plants' roots. These worms attack the U.S. potato crop only in New York state.

The "white" potato-cyst nematode, G. pallida, is a major pest of potato outside the United States, and regulators are making every effort to block its entry into this country. Built-in resistance to this pest was developed as insurance, in case races of this more aggressive nematode are accidentally introduced. In countries in South America and Europe where G. pallida occurs, it causes considerable economic damage to potatoes.

The new germplasm is the result of cooperative efforts by Agricultural Research Service plant pathologist Bill Brodie, at the Plant, Soil and Nutrition Laboratory, Ithaca, N.Y., and researchers at Cornell University-Ithaca and the International Potato Center, Lima, Peru.

Brodie says the source of this resistance is germplasm obtained in 1984 from the International Potato Center. Seeds that resist the two nematodes are being released by the Cornell University Agricultural Experiment Station and ARS. The germplasm will be deposited in the U.S. Potato Introduction Station Germplasm Collection at Sturgeon Bay, Wis., for long-term storage in the ARS potato gene bank.

Some of the new germplasm also resists potato virus Y, which can be spread by aphids and also affects tobacco, tomatoes, peppers and many other plants.

Scientific contact: Bill B. Brodie, ARS Plant, Soil and Nutrition Laboratory, Ithaca, N.Y., phone (607) 255-2158, fax (607) 255-2739, ars-ithaca@cornell.edu.