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ARS Home » Pacific West Area » Riverside, California » National Clonal Germplasm Repository for Citrus » Research » Research Project #438790

Research Project: Preservation of Citrus Germplasm and Improving Pathogen Detection

Location: National Clonal Germplasm Repository for Citrus

Project Number: 2036-21000-011-014-S
Project Type: Non-Assistance Cooperative Agreement

Start Date: Sep 1, 2021
End Date: Mar 31, 2023

This project has three major objectives: (1) to assist in the testing and elimination of bud transmitted diseases and release of citrus germplasm not presently in the Repository; (2) the enhancement and improvement of detection of the bud transmitted diseases of citrus; and (3) research into other areas having an effect on the phytosanitary status of citrus or date palms.

The ARS and UC citrus collections include about 2000 accessions, 500 of which are designated high priority and are maintained clonally in insect-proof screenhouses in Riverside and on the UC Lindcove Research and Extension Center in Exeter, CA. These accessions have been pathogen-tested and are believed to be ‘clean.’ The university PI and ARS Repository are collaborators on a USDA APHIS MAC project through which citrus material is brought into California from Florida for evaluation under California growing conditions while it is undergoing investigation for HLB resistance and/or tolerance in Florida. This germplasm will be slated for cryopreservation. A subset of these will be tested for viability and presence of contamination in culture and further indexed for the presence of pathogens. The UCR PI provides expertise in plant pathology and pathogen detection and will contribute training and oversight on laboratory analyses for plant pathogens. In addition, he will provide germplasm for cryo-preservation from his collection of disease-free commercially important citrus cultivars. The USDA ARS scientists are responsible for genetic resource management and will contribute the expertise in the preparation of material for cryopreservation. This collaboration is mutually beneficial in that both parties are interested in genetic resource collections, long-term preservation of germplasm viability, and clean propagative stock of citrus. The longer term impact of this collaborative project will be a collection of citrus genetic resources that is disease-free and protected from future disease transmission, with many accessions cryopreserved for long-term conservation. We also expect more efficient methods to evaluate germplasm viability and detect the presence of pathogens in genetic resource collections.