University of California, Riverside
College of Natural and Agricultural Sciences
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Current Research Projects

PictureThe Citrus Variety Collection serves as a resource for a myriad of research projects from scion and rootstock breeding for the improvement of commercial varieties to the study of the biological activities of citrus limonoids as anticancer agents. Since 1997, 38 have used the collection, conducted by researchers at UC Riverside, University of Arizona, Auburn University, and USDA. Today, as the world of science has expanded, so too have the ways in which the Citrus Variety Collection is used:

The Collection is the source of research materials for ongoing investigations of the anticarcinogenic activity of citrus limonoids by Drs. D. Hasegawa and G. Manners of the USDA.

L. Walling, UCR Professor of Botany and Plant Sciences, employs the tools of molecular genetics to reduce citrus seed set and enhance citrus tolerance to pests and diseases.

At University of Arizona, G. Wright breeds new scion and rootstock citrus varieties that will thrive in challenging desert environments.

UCR Professor of Botany and Plant Sciences M. Roose investigates phylogenetic relationships among Citrus types and directs both scion and rootstock breeding projects which use detailed genetic mapping and recombinant DNA technology as well as traditional breeding techniques.

Research performed in Citrus Variety Collection by the USDA National Clonal Germplasm Repository for Citrus and Dates includes molecular characterization of sexually-derived accessions, evaluation of rootstock physical properties, as well as fruit quality evaluations. The Citrus Variety Collection also serves as a source of materials for indexing and cleanup by the NCGRCD.

C. Martin at Auburn University in Alabama relies upon the resources of the Citrus Variety Collection to revise the taxonomy of Citrus and its relatives based upon analysis of the chloroplast and nuclear genomes.

T.L. Kahn and T. Siebert utilize the collection and three citrus Evaluation Blocks each year to evaluate new citrus varieties for trueness-to-type and commercial potential.

If you would like more information about the variety evaluations of T. L. Kahn and T. Siebert, contact T. Kahn at

How to Support the Collection

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