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History of

the Program

The fruit tree program is one of the original National Clean Plant Network specialty crops, and indeed, predates NCPN by over 50 years. Beginning in 1955 as the Interregional Research Project IR-2 at Washington State University’s Irrigated Agriculture Research and Extension Center in Prosser, Washington, the program’s goals were to:

  • Obtain cultivars of desirable deciduous fruit trees

  • Verify their virus-freedom by intensive diagnostic procedures

  • Maintain the cultivars in contained repositories

  • Distribute propagating materials to cooperators as foundation clones for research or for release to industry.


In 1992 the program was renamed as National Research Support Project-5 and continued providing these essential services to the U.S. fruit tree industry, as well as developing, evaluating, and implementing new technologies for the virus detection and the elimination of viruses. This program was credited with significant reduction in disease incidence in the supported crops across the U.S. and was estimated in 2003 to provide benefits to nurseries, growers, and consumers on the order of $227 million per year.

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A greenhouse at the Irrigated Agriculture and Extension Center in Prosser, Washington in the 1950s.

In 2010, the NRSP-5 program in Prosser, WA became part of the newly founded National Clean Plant Network, leading a nation-wide effort with supporting centers at Foundation Plant Services in Davis, CA, and the Southeastern Budwood Program in Clemson, SC.


We continue to obtain, diagnose, and retain desirable pome and stone fruit cultivars in contained repositories to prevent reinfection, with outdoor budwood blocks for local production.