'UC Wolfskill' walnut tree with fruit
The ‘UC Wolfskill’ walnut, designed with growers in mind, will harvest earlier and provide the quality, yield and color of Chandler, the state’s leading variety. (Jeanine Hasey)

New UC Davis walnut variety builds upon tremendous legacy

A new walnut variety will provide growers a way to harvest earlier and boost the harvest efficiency of California's $1.6 billion walnut industry. It also builds upon the legacy of the UC Davis Walnut Improvement Program.

The new variety, named ‘UC Wolfskill,’ has yield, quality and color similar to the Chandler cultivar, which was released by the Walnut Improvement Program in 1979. Chandler has since dominated the state’s walnut market – the largest in the nation with 99 percent of total production happening in the Golden State – for its reliability, desirable color, and late season harvest.

‘UC Wolfskill,’ which is named after the university’s experimental orchards donated by the Wolfskill family in 1938, hopes to change things.

Bred by Chuck Leslie with help from Gale McGranahan and Pat J. Brown, associate professor in the Department of Plant Sciences, for the UC Davis Walnut Improvement Program, ‘UC Wolfskill’ is a cross between Chandler and Solano, another UC Davis cultivar.  Combining the best qualities of both, growers can expect to reap the color, shape and convenience of Chandler walnuts weeks earlier thanks to the influence of Solano.

“The California walnut industry needs earlier harvesting walnut varieties to provide efficient use of harvesting, drying and processing equipment,” said Leslie.

Pat Brown also notes that the earlier harvest date of ‘UC Wolfskill’ will allow growers to lengthen their overall harvest season when grown alongside the traditional Chandler trees. Importantly, in blind quality evaluations by commercial graders, who value a walnut based on its color and how well it halves, ‘UC Wolfskill’ was often not distinguished from Chandler.

The variety continues the mission of the UC Davis Walnut Improvement Program to increase yield and to generally support the walnut industry in California. In development for 18 years, researchers originally planted and evaluated the new variety at UC Davis before field trials with growers began in 2011.

“The commitment of our walnut growers, as collaborators, is the foundation that makes this release possible,” said Michelle Connelly, executive director of the California Walnut Board. “The Board is extremely grateful for the long-term partnership of our growers and the UC, in finding innovative solutions that help us solve for critical needs.”

The California Walnut Board funded the research. UC Wolfskill is currently available to California nurseries for propagation in California and sales to growers throughout the United States. Nurseries interested in propagating and selling this cultivar may obtain a license from UC Davis InnovationAccess.

(Article adapted from the original by Amy Quinton, with edits and additions by Matt Marcure)

Media contact(s)

Amy Quinton, News and Media Relations, 530-601-8077, amquinton@ucdavis.edu 

Pat J. Brown, Plant Sciences, pjbrown@ucdavis.edu 

Chuck Leslie, UC Davis Walnut Improvement Program, caleslie@ucdavis.edu 

For more information

Denise Meade, InnovationAccess, 530-754-8674, dlmeade@ucdavis.edu

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