Project Number: 5354-21000-012-00
Project Type: Appropriated

Start Date: Aug 23, 2002
End Date: Aug 22, 2007

Objective:
Develop quantitative PCR assays to identify alfalfa plants with high levels of resistance to Phytophthora medicaginis, Fusarium oxysporum, and Verticillium albo-atrum. Develop alfalfa germplasm with high levels of resistance to diseases caused by Aphanomyces euteiches, P. medicaginis, F. oxysporum f. sp. medicaginis, and V. albo-atrum by selecting resistant plants with quantitative PCR assays specific for each pathogen. Screen bean breeding lines and plant introduction (PIs) accessions of bean for resistance to severely pathogenic strains of AMV and CMV. Develop quantitative PCR assays to rapidly and accurately genotype bean plants for the bc-12 and I genes, which confer resistance in bean to Bean Common Mosaic Virus (BCMV) and Bean Common Mosaic Necrosis Virus (BCMNV).

Approach:
Quantitative PCR assays will be developed that are specific to the soilborne alfalfa pathogens Phytophthora medicaginis, Fusarium oxysporum f. sp. medicaginis, and Verticillium albo-atrum. Populations will be screened for resistance by quantifying pathogen DNA content in extracts from bulked plant samples. Selection of resistant plants for germplasm enhancement will be based on the use of these assays to detect differences in pathogen levels between plants that appear phenotypically similar. Selected plants will be crossed in the greenhouse and progeny resulting from these crosses will be used for subsequent cycles of selection for resistance. An enhanced germplasm will be developed based on simultaneous selection for resistance to A. euteiches and P. medicaginis, another germplasm will be developed with enhanced resistance to F. oxysporum f. sp. medicaginis, and a third enhanced germplasm will be developed based on selection for resistance to V. albo-atrum. Sources of resistance will be identified in bean to a severe disease complex involving Cucumber Mosaic Virus and Alfalfa Mosaic Virus. Quantitative PCR assays will be developed to efficiently genotype beans for the bc-12 and I virus resistance genes.Formerly 5354-21000-012-00D (8/02).

Project Team

Vandemark, George Alva, Ashok Larsen, Richard - Rick

Project Annual Reports

FY 2003

Related National Programs

Rangeland, Pasture, and Forages (205)   Plant Diseases (303)

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