Geneticists Phil Miklas (left) and George Vandemark analyze results of quantitative polymerase chain reaction assays used to rapidly genotype bean plants for disease resistance. Click the image for more information about it.

New Kidney Bean Germplasm Line Resists Common Bacterial Blight Disease

By Jan Suszkiw
September 22, 2005

A new germplasm line dubbed "USDK-CBB-15" is now available for breeding new varieties of dark red kidney beans that can resist common bacterial blight.

Caused by the pathogen Xanthomonas axonopodis pv. phaseoli, bacterial blight is an endemic disease affecting bean crops east of the U.S. Continental Divide. Antibiotic treatment, clean-seed programs and sanitation are standard control measures. However, resistant crops are the key defense, according to Phil Miklas, a plant geneticist in the Agricultural Research Service's (ARS) Vegetable and Forage Crops Production Research Unit in Prosser, Wash.

In susceptible bean plants, the disease symptoms include large brown blotches with lemon-yellow borders on leaf surfaces and small, discolored seed in infected pods. Severe outbreaks can cause yield losses of up to 40 percent in susceptible crops.

Miklas developed USDK-CBB-15 using marker-assisted selection, a method of detecting inherited genes that speeds the screening of plants for desired traits such as disease resistance. USDK-CBB-15 is the product of kidney bean crosses that Miklas made to incorporate resistance genes from the Great Northern bean cultivar "Montana Number 5" and the breeding germplasm line XAN 159.

James Smith, in ARS' Crop Genetics and Products Research Unit at Stoneville, Miss., and Shree Singh, with the University of Idaho at Kimberly, collaborated with Miklas on the new kidney bean's development, testing and evaluation. They will post a registration notice with detailed information on USDK-CBB-15 in an upcoming issue of the journal Crop Science. Miklas is handling seed requests.

The United States is the sixth-leading producer of edible dry beans, generating farm sales of $451 million in 2001-03, according to the U.S. Department of Agriculture's Economic Research Service. Per-capita consumption of edible dry beans is 6.8 pounds, according to ERS, with kidney beans finding favor in soups, salads, chili and other dishes. Beans are also an excellent source of antioxidants, fiber, protein, and vitamins for healthy diets, Miklas notes.

ARS is USDA's chief in-house scientific research agency.