New Dry Edible Bean Resists Bacterial
Disease By Jan
Suszkiw June 29, 2007
A new germplasm line named "ABC-Weihing" is now available for breeding
high-yielding varieties of great northern beans that can resist common
Caused by the pathogen Xanthomonas campestris 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. But crop resistance is the keystone defense,
Miklas, a geneticist in the Agricultural Research Services (ARS)
and Forage Crops Production Research Unit, Prosser, Wash.
In susceptible bean plants, 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 and Carlos Urrea, a University of
Nebraska (UN) bean breeder, developed ABC-Weihing using marker-assisted
selection, a method of detecting inherited genes that is faster than
conventional screening of plants for disease resistance and other traits.
ABC-Weihing is the offspring of several crosses the scientists made, starting
in 1997, between a Great Northern bean cultivar and "XAN 159," a germplasm
In greenhouse tests, ABC-Weihing also resisted eight strains of bean
rust, as determined by ARS plant pathologist
Vegetable Laboratory, Beltsville, Md., and all non-necrotic strains of bean
common mosaic. ABC-Weihing's upright growth also helped protect it from
soilborne assault by white mold.
Other features include white flowers that bloomed 45 days after
planting and seed that was slightly larger than "Matterhorn," a commercial
check variety used in trials in North Platte, Neb., Carrington, N.D., and
elsewhere. In those tests, ABC-Weihing had an average seed yield of 1,869
pounds per acre versus 1,896 pounds per acre for Matterhorn.
Detailed information on ABC-Weihing will appear in an upcoming issue
of Crop Science. Urrea 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
ARS is USDAs chief scientific