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
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
Miklas, a plant geneticist in the Agricultural Research Service's (ARS)
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
Smith, in ARS'
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
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.