Citrus scion breeding at the University of California Riverside

The UCR Citrus Breeding Program develops new scion cultivars using mutation breeding and hybridization selection approaches.
The program is primarily funded by California growers through the California Citrus Research Board.
After initial selection of promising candidates and development of a clean bud source through the Citrus Clonal Protection Program, candidate selections are tested in replicated trials at four locations in different production regions of California.
These trials are at field stations of the University of California and with private growers.
Release decisions are based on data from these trials, thus most new releases have two cycles of field evaluation.
We are developing a system to allow “grower trials” that will allow more growers to participate in evaluation of potential cultivars.
However, recent court cases complicate obtaining yield records from grower trials because fruit sales bar US plant patents after one year.
Cultivars are owned by The Regents of the University of California and licensed to California nurseries for propagation and sale.
Exclusive licenses are not granted within California.
Distribution outside California starts 3 years after California release and is managed by a small number of business partners with exclusive licenses by country.

XV International Citrus Congress

M.L. Roose, T. Siebert Wooldridge, K. Trunnelle, T. Kahn, C.T. Federici, D. Seymour

mutation breeding, marker-assisted selection, plant patents

https://doi.org/10.17660/ActaHortic.2026.1448.100