Location: Tropical Crops and Germplasm Research2011 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. In addition, advanced lines are being tested in the United States (U.S.) for adaptation, photoperiod insensitivity and for the presence of the target trait. Trials are currently underway with these materials in Nebraska (for drought tolerance), Idaho [Common Bacterial Blight (CBB) and white mold resistance], and New York (root rot resistance). A recombinant inbred line (RIL) population (300 lines) was developed during the last fical year for drought evaluation and now is being used in experimental evaluations in Nebraska and Puerto Rico. An Association Mapping (AM) population was developed as part of the Bean CAP project. The RIL and the AM populations were evaluated for their response to drought in Fiscal Year 2011. Another large RIL population (300 lines) developed by ARS is being evaluated by a collaborator for work on nutrition traits. A RIL population, developed at the Tropical Agriculture Research Station (TARS) in collaboration with Michigan State for the study of the genetics of leafhopper resistance was tested in a second set of trials under leafhopper pressure in the field in Michigan and in Puerto Rico. The EMS (ethyl methanesulfonate) mutant population (>2,500 lines) is being evaluated of specific seed traits at two ARS laboratories, and at Agriculture and Agri-Food Canada. A manuscript on the release of two black bean germplasm lines with tolerance heat and drought, and resistance to CBB and root rot, has been accepted by the Journal of Plant Registrations for publication.
1. Release of dry bean germplasm with abiotic and biotic stress tolerance. High ambient temperature stress, drought stress, root rot diseases, and common bacterial blight cause widespread yield reduction in common bean in low-land tropical environments and in warm temperate environments throughout the world. This complex of environmental and plant pathogen-derived stresses often occur together, and may become more significant due to climate change. However, common bean cultivars that combine tolerance to this complex are not available. The breeding for and release of common bean germplasm with enhanced levels of tolerance to these varied constraints is therefore critical for meeting present and future food security requirements. TARS-MST1 (Tropical Agriculture Research Station-Multiple Stress Tolerant 1)and SB-DT1 (Shuttle Breeding-Drought Tolerant 1), were developed by the United States Department of Agriculture-Agricultural Research Service, the University of Nebraska Agricultural Research Division, and the University of Puerto Rico Agricultural Experiment Station. These black bean lines were selected for multiple stress tolerance, including tolerance to high ambient temperature and drought stress, and resistance to bacterial blight and root rot. They incorporate exotic sources of stress tolerance, thus serving to diversify U.S. common beans. These lines can be used by farmers for common bean production in low input environments. In addition, breeding programs can use these germplasm lines in order to improve yield of common bean in existing production regions and in marginal environments.
Ramirez-Builes, V.H., Porch Clay, T.G., Harmsen, E.W. 2011. Evaluation of the efficiency of water use in common bean under drought and non-stress conditions in the greenhouse and field. Agronomy Journal. 103:1206-1215.