Agricultural Research Service - USDA

Germplasm line USPT-ANT-1 harbors a single gene, Co-42, which confers resistance to the most-destructive races of Colletotrichum lindemuthianum, the fungus that causes anthracnose, notes Phil Miklas. A plant geneticist at the Agricultural Research Service Vegetable and Forage Crops Production Research Unit, Prosser, Wash., he is handling seed requests.

In dry edible beans, athracnose causes disease symptoms that include unsightly cankers on the plant stem, pods and seeds. Endemic to Michigan, New York and other Great Lakes states, anthracnose most recently emerged as a threat to 350,000 acres of susceptible pintos grown in Minnesota and North Dakota. Those two states, plus Michigan, produce about half the nation's $629 million dry edible bean crop.

Commercial pinto beans derived from the new germplasm line would be the first to resist anthracnose, according to Miklas. Chemical fungicides, clean-seed programs and sanitation are the standard control measures. But crop resistance is the keystone defense. To develop USPT-ANT-1, Miklas used marker-assisted selection, a gene-detecting technique that saves the time involved in infecting plants and then waiting to visually check them for resistance traits. USPT-ANT-1 is the product of crosses, and brackcrosses (used to eliminate undesirable traits), made among established pinto bean cultivars, including Othello, Maverick and Buster, with SEL 1308 providing the Co-42 gene.

In field trials, USPT-ANT-1 produced seed yields that were 107 and 90 percent of Othello at test sites in Prosser and Idaho, respectively. USPT-ANT-1 also compared favorably to Buster, another commercial check variety. In those tests, the germplasm line reached its peak growth, or maturity, nine to 14 days later than Othello and four days later than Buster.

Jim Kelly, at Michigan State University; Shree Singh, at the University of Idaho; and Ken Grafton, at North Dakota State University, collaborated with Miklas on the pinto's development, testing and evaluation.