Location: Tropical Crops and Germplasm Research2010 Annual Report
1a. Objectives (from AD-416)
Utilization of untapped genetic diversity through the conversion of germplasm and the incorporation of key traits into common bean improvement programs for abiotic stress tolerance and disease resistance. Application of genetic analysis and TILLING (targeting induced local lesions in genomes) for identification and mapping of important traits in common bean. Development and release of improved germplasm for specific agriculturally important biotic and abiotic stress tolerance traits and identification of associated molecular markers.
1b. Approach (from AD-416)
Increase genetic diversity in common bean germplasm through conversion of specific abiotic and biotic traits from tropical germplasm. Elucidate the genetics of drought and heat tolerance, and other agriculturally important traits, using molecular markers, TILLING, and classical genetic approaches. Develop germplasm with improved disease resistance and abiotic stress tolerance through phenotypic selection and marker assisted selection.
3. Progress Report
Breeding lines in the conversion program were advanced using the inbred backcross method or simple backcrossing. In addition, advanced lines with specific traits of interest are being tested in the U.S. for photoperiod insensitivity and for the presence of the target trait. Trials are currently underway with these materials in Nebraska, Michigan, North Dakota, and New York. A RIL (recombinant inbred line) population, developed at TARS in collaboration with Michigan State University for the study of the genetics of leafhopper resistance, was tested under leafhopper pressure in the field in Michigan and in Puerto Rico. Two RIL populations, for the study of the genetics of drought tolerance in common bean, were advanced to the F6 generation. One population is currently being tested at the University of Nebraska and the other at Michigan State University. The EMS (ethyl methanesulfonate) mutant population (>2,500 lines) is being evaluated of specific seed traits at two ARS laboratories, while over 500 additional M1 lines were generated in Puerto Rico. A release of two kidney bean germplasm lines with heat tolerance was accepted for publication in the HortScience journal. Black bean germplasm lines, with heat, drought, and common bacterial blight resistance, are being prepared for release.
1. Common bean (Phaseolus vulgaris L.) reproductive development is particularly sensitive to high temperature stress, resulting in yield reduction. Two kidney beans, TARS-HT1 and TARS-HT2, were developed that are tolerant to high temperature conditions. These kidney beans were developed cooperatively by the USDA-ARS Tropical Agriculture Research Station (TARS), the University of Puerto Rico, Cornell University, and the University of Tennessee. TARS-HT1 is tolerant to high day and night-time temperature stress and TARS-HT2 is tolerant to high daytime temperature stress and moderate nighttime temperature stress. The use of TARS-HT1 and TARS-HT2 can improve yield under hot summer conditions for farmers in regions prone to high temperature stress. In addition, they can be used for improving heat tolerance in other large-seeded beans through breeding and selection.