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United States Department of Agriculture

Agricultural Research Service


Location: National Clonal Germplasm Repository for Citrus

2008 Annual Report

1a. Objectives (from AD-416)
Maintain high quality of and upgrade citrus variety collection and citrus relative collection.

1b. Approach (from AD-416)
Acquire new potential accessions for the citrus variety collection and citrus relative collection and NCGRCD protected screenhouse collection, evaluate accessions and potential access, update databases appropriately, and maintain collections in good order for efficient utilization.

3. Progress Report
The UCR Citrus Variety Collection continues to be one of the most extensive collections of citrus diversity in the world with over 1000 acessions. This living collection of citrus germplasm serves as a resource for basic and applied research and a wide range of extension activities. The Citrus Varieties Collection has three locations, the central one at UC Riverside and two smaller collections of citrus relatives at South Coast Research and Extension Center (SCREC) in Irvine, CA and the Coachella Valley Agricultural Station (CVARS) in Thermal, CA. The NCGRCD and the UCR Citrus Variety Collection staffs work closely together to support the missions of both programs through activities which maintain and enhance the collection and research to characterize accessions. The most significant accomplishment in the past year was the completion of data collection for our evaluations of the genera allied with Citrus, the ‘citrus relatives’. The approximately 600 trees of the different relative taxa in the subfamily Aurantiodeae in the Rutaceae in the collection were evaluated for 80 different descriptors such as growth habit, spine length, lamina shape and width, flower arrangement and color, length of anthers, time of flowering and fruiting, fruit weight and shape, oil gland size, pulp texture, vesicle length, seed weight, and seed embryology. The project was divided into three parts: vegetative characteristics, flower characteristics, and fruit/seed characteristics. Characterization of the 20 different leaf and tree descriptor was completed first, then the fruiting and flowering times for each accession in each location. The documentation of fruiting and flowering times is not only part of the descriptor data, but is also essential in determining when the most appropriate time is for gathering flowers and/or fruit in future collections for characterization. An excel file has been developed to enable uploading the information to the GRIN database. ADODR monitored activities by meetings and site visits.

4. Accomplishments

Last Modified: 05/24/2017
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