A new potato that's highly resistant to late blight—the world's worst potato disease—is now available from ARS for plant breeders. Scientists hope the new spud, called AWN86514-2, can be bred with top-rated experimental potatoes or commercially successful varieties to boost their resistance to late blight. This fungal disease caused the Irish potato famine in the 1800s. New, more aggressive, fungicide-resistant strains of the disease-causing fungus have appeared in recent years. Breeding and testing to incorporate the new potato's resistance in new commercial varieties for farmers may take 6 to 10 years or more. In experiments by ARS scientists and colleagues in eight states and Mexico, AWN86514-2 held up well when attacked by new strains of the disease fungus, Phytophthora infestans. The new tuber also resisted attack by viruses that cause two other potato diseases, potato virus Y and potato leafroll virus. The potato's parents are an ARS-developed french fry variety called Ranger Russet and a spud selected from a collection sent to ARS by Poland's potato breeding institute. The average American eats about 143 pounds of potatoes a year, making spuds America's favorite vegetable.
Small Grains and Potato Research Unit, Aberdeen, ID
Dennis L. Corsini, (208) 397-4181, dcorsini@uidaho.edu

A new mildew-resistant wheat breeding stock from ARS and cooperating scientists has surprised plant pathologists by warding off every strain of powdery mildew in their laboratory gauntlet. Previously, eight strains out of ten was the best any wheat could do. Commercial seed companies can use the breeding line, called NC97BGTAB-10, as a hybrid-parent to build mildew resistance into profitable, new soft red wheat varieties for farmers. Bakery cookies and cakes get their delicate texture from flour made with soft red winter wheat, which grows east of the Mississippi River. Powdery mildew hits the East's soft wheat types the hardest, costing growers between $2 million and $3 million annually. Scientists developed the new line from wheat's hardy wild ancestors from the Middle East. The work was a collaborative effort with North Carolina State University.
Plant Science Research Unit, Raleigh, NC
Steven Leath, (919) 515-6819, Steven_leath@ncsu.edu

Home gardeners in the southeastern U.S. can soon grow a new southern pea that is ideal for producing fresh peas suitable for freezing. The new pea, "Petite-N-Green," can also be harvested when fully dry and stored as an attractive pack of dry peas. Developed by ARS scientists under a Cooperative Research and Development Agreement with Western Seed Multiplication, Inc., Oglethorpe, GA, the pea is the product of 8 years of intensive breeding. The plant grows low and bushy, producing pods in 70 to 76 days. Each pod is slightly curved, about 5½ inches long with 14 peas. The dry peas are small—100 peas weigh about 1/3 ounce—and have a smooth seed coat. They can be restored to their near-fresh green color by blanching in boiling water for 3 minutes. Western Seed has the right of first refusal to an exclusive license to market the new cultivar. Breeders' seed will be maintained by the U.S. Vegetable Laboratory, Charleston, SC. Genetic material will be stored in the National Plant Germplasm System and will be available for future breeding efforts. Petite-N-Green seeds should be available to home gardeners by spring of the year 2000.
U.S. Vegetable Laboratory, Charleston, SC
Richard L. Fery, (843) 556-0840, rfery@awod.com

New peanut cultivars that withstand the root-knot nematode could come from a collection of resistant germplasm identified by ARS scientists. If breeding is successful, new cultivars would be commercially available within 5 years. For farmers, this won't be a moment too soon. Varieties they grow today generally can't survive severe nematode attack without chemical nematicide. Such attacks cost U.S. farmers up to $30 million annually in losses and chemical controls. The nematode, a microscopic roundworm, inflicts its costly mischief by forming galls or knots on the peanut plant's roots, blocking nutrients and sapping vital energy. Female nematodes lay thousands of eggs on the roots, setting up farmers for a fresh round of losses next season. Researchers hope to break this cycle by crossing high-yielding cultivars with resistant plants from a collection of 36 strains that deprive the pests of a chance to feed and lay eggs. In greenhouse trials, scientists observed a 70 percent reduction in the number of root galls and egg clusters on resistant plants compared with Florunner, a susceptible variety. The two most resistant plants, from Asia, showed a 90 percent reduction.
Nematode, Weeds and Crops Research, Tifton, GA
Corley Holbrook, (912) 386-3176, nfla@tifton.cpes.peachnet.edu

Peanut breeders have a rich new source of genes to improve commercial peanut varieties, thanks to ARS-supported plant explorations. In 1995 and 1996, an ARS plant explorer and colleagues from Texas, Colombia and Ecuador traveled throughout Ecuador collecting more than 200 samples of native peanut varieties, commonly known as landraces. For centuries, indigenous farmers in Ecuador have selected peanuts that grow best under local conditions and have the characteristics they prize. Ecuadorian cultures have various uses for peanuts and select seed for specific traits, such as white peanuts for use in candy. The landraces collected include all six botanical varieties of peanut (Arachis hypogaea): hirsuta, hypogaea, fastigiata, peruviana, aequatoriana and vulgaris. Several of the landraces collected were previously unknown to science. Resistance to pests, diseases and environmental stresses are a few of the useful traits that may be found in the Ecuadorian landraces. The mission filled gaps in the U.S. peanut collection and reestablished a national peanut germplasm collection in Ecuador. In follow-up activities, the U.S, and Ecuador worked together to multiply and characterize the collected germplasm so that it can be used by peanut breeders around the world.
Plant Exchange Office, National Germplasm Resources Laboratory, Beltsville, MD
Karen A. Williams, (301) 504-5421, kwilliams@ars-grin.gov

Native wild onion plants may be easier to propagate from seed collected in the wild than from seed produced in a greenhouse or conventional field. To stock seed banks of these and other plants, ARS scientists are increasing their use of the approach known as in situ or on-site preservation. The agency maintains a network of repositories, known as the National Plant Germplasm System, to store seeds and other reproductive tissues of crop plants and their wild relatives. For researchers, this network is an invaluable tool for finding new genetic sources of disease resistance and other beneficial characteristics to breed into commercial crops. U.S. cultivated onion and garlic crops are worth more than $900 million annually. But more than 60 American species in the onion family grow in wild rocky places. Many species have not been incorporated into the repository system because they are difficult to propagate in traditional crop settings. So, scientists are trying to propagate them in situ by identifying areas where they grow naturally and collecting seeds from wild plants for storage. As a pilot test, they're looking at three species of wild onion in Washington: Douglas' onion (Allium columbianum) and Geyer's onion (A. geyeri) at the Turnbull National Wildlife Refuge west of Spokane and fringed onion (A. fibrillum) in the Umatilla National Forest outside Dayton.
Western Regional Plant Introduction Station, Pullman, WA
Barbara Hellier, (509) 335-3763, bhellier@mail.wsu.edu

Finding and preserving a native wild grape called Vitis rupestris Scheele was the mission of an ARS scientist who drove and hiked more than 12,000 miles in the United States last summer. Rock grape is a prized rootstock because of its excellent resistance to diseases and insects and its ability to adapt to harsh environmental conditions such as drought. Finding wild rock grape plants undisturbed in their native habitat is a vital first step toward preserving the species' genetic potential for developing new grape varieties. Rock grape typically grows along rivers and creeks, on gravel bars and in areas with large boulders. Flooding may uproot and redeposit the plants or transport the fruits downstream, where seeds germinate. The ARS scientist looked for the plants in 60 waterways in 10 states—from Pennsylvania to Texas—where the plants had previously been collected. Because of stream channeling or other changes that eliminated the plant's habitat, she found it on only two dozen of the 60 waterways. At each site, she measured the plants, recorded physical data on 238 of the plants and took leaf samples for genetic screening. Her analyses identified populations that differed in specific favorable traits. Another ARS scientist at Geneva, NY, collaborated on screening the plants and evaluating plant populations for their genetic diversity using DNA markers. From these analyses, the scientists have proposed seven populations as in situ conservation sites.
National Germplasm Resources Laboratory, Beltsville, MD
Diane S. Pavek/Edward J. Garvey, (301) 504-5692, peodp@ars-grin.gov
Plant Genetic Resources Unit, Geneva, NY
Warren F. Lamboy, (315) 787-2359, wfl1@cornell.edu

The nutritional quality of sorghum, the world's fifth leading cereal grain, could get a boost from 30 new breeding lines. ARS collaborated with Texas A&M University on developing and releasing the new lines as part of an ongoing program to improve sorghum. Some of the lines have higher levels of carotene, a nutrient the body converts to vitamin A. The new lines are tropical sorghums genetically converted to grow in temperate areas. As a result, they can produce an early grain crop in temperate areas, where long summer days mean more sunlight than along the Equator. The researchers developed the lines by crossing late-maturing sorghums from India, Ethiopia and Nigeria with early-maturing varieties. The scientists also released 30 partially converted lines that may be useful to researchers and breeders. ARS is exploring new biotechnology procedures to speed up sorghum breeding. By conventional methods, converting tropical sorghum germplasm into plants that will grow in temperate regions takes 5 to 10 years.
Tropical Agriculture Research Station, Mayagüez, PR
Jeff Dahlberg, (787) 831-3435, ext. 241, jdahlberg@ars-grin.gov

DNA markers on the new soybean genome maps allow rapid identification of plants carrying the two major genes that give resistance to the soybean cyst nematode. This pest robs U.S. farmers of an average of 220 million bushels of soybeans a year. The genome maps are proving useful in the ongoing hunt for two or three additional minor resistance genes. ARS scientists at Beltsville, MD, found and mapped almost 700 genetic markers that serve as road signs to genes on the soybean genome highway. Collaborators in the mapping research include researchers with the University of Nebraska at Lincoln, the University of Utah at Salt Lake City, ARS at Ames, IA, and a private company, BioGenetic Services, Inc. of Brookings, SD. ARS and Nebraska scientists are using the soybean maps for another first: identifying rare desirable genes in crosses between wild and commercial soybean lines. The genome maps enable them to pinpoint genetic material, including possible yield enhancing genes. Without such information, the chances of improving yield by crossing wild soybean (a vine-like weed) and commercial soybean would be unlikely. The mapping research was funded in part by the United Soybean Board.
Soybean and Alfalfa Research Laboratory, Beltsville, MD
Perry B. Cregan, (301) 504-5070, pcregan@nal.usda.gov