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ARS Home » Pacific West Area » Riverside, California » National Clonal Germplasm Repository for Citrus » Research » Research Project #441816

Research Project: USDA-ARS National Clonal Germplasm Repository for Citrus & Dates Citrus Clean Plant Center, Riverside

Location: National Clonal Germplasm Repository for Citrus

Project Number: 2036-21000-011-033-I
Project Type: Interagency Reimbursable Agreement

Start Date: Oct 1, 2021
End Date: Sep 30, 2022

Goal 1: Clean up (therapeutics + diagnostics) of citrus germplasm introduced or maintained under quarantine. Objective 1.1: Citrus germplasm introduction. Germplasm will arrive at NCGRCD quarantine facilities at the request of stakeholders or as determined by center management. Objective 1.2: Pathogen testing and diagnosis of citrus germplasm. Laboratory and biological testing of citrus germplasm will be carried out at the NCGRCD facilities prior to therapeutics to assess pathogen status and after therapeutics to determine effectiveness of the therapeutics. New and modified diagnostic protocols will be implemented as they become available. Objective 1.3: Therapeutics of citrus propagative material. Therapeutics for the elimination of citrus pathogens (shoot-tip grafting, heat therapy) will be carried out at the NCGRCD facilities. Goal 2: Maintenance of clean citrus propagative material source trees in protective structures. Objective 2.1: Maintenance of clean citrus germplasm. Clean citrus accessions maintained in protective structures will be observed and repropagated as necessary. Trees will be horticulturally managed for optimum health and propagule production. Objective 2.2: Retesting of clean citrus germplasm. Protected accessions will be retested to meet State and Federal standards. Seed source trees in the field will be re-tested to meet State standards. Objective 2.3: Back up of clean citrus germplasm. When sufficient material is available on newly sanitized, it will be sent to NLGRP for long-term cryopreservation. Objective 2.4: Distribution of clean citrus propagative material. Clean citrus propagative material will be distributed upon request to qualified institutions and individuals.

Citrus importation and clean up is performed under PCIP-18-00441 (renewed 2020-10-05), which is on file at USDA-APHIS-PPQ Permits Unit. The method followed is summarized as follows: initial pathogen testing to determine incoming pathogen status, followed by therapeutics (shoot-tip grafting or thermotherapy). After therapeutics, the resultant plants are screened by laboratory testing, after which a select plant of each genotypes is indexed biologically, followed by final lab tests. Plants testing negative for all known graft transmissible pathogens are petitioned to be released from quarantine.