Potential Sources of Resistance to White Mold
April 01, 2001
Jack Rasmussen, Department of Plant Pathology,
and Ken Grafton, Department of Plant Sciences,
NDSU, Fargo, ND
White mold is the most persistent and economically-damaging disease of dry beans in the Northarvest production area. The most efficient way to control white mold is through genetic resistance. However, most widely-grown dry bean cultivars are susceptible to the disease. The objectives of this research project are to find new sources of resistance to white mold and to incorporate that resistance into material that can be used by the breeding program. Toward those goals, we evaluated in the greenhouse over 100 dry bean lines originally collected in Central and South America and maintained by the USDA. This CASA core collection includes genotypes or lines of various dry bean types (pintos, black beans, etc.) that are genetically different from our varieties. Collectively, these core collections contain potentially valuable sources of genetic resistance for the Northarvest production area. Included in this genetic diversity may be resistance to white mold. Several lines were found to posses high levels of resistance to white mold, as determined by tests performed in the greenhouse. Genetic crosses were established between these South and Central American lines and Othello, a pinto bean adapted to the Northarvest region. Progeny of these crosses are being developed into recombinant inbred lines that can be tested in the field to identify potential white mold resistant parents for the breeding program.