‘UC Wolfskill’ walnut will allow earlier harvest

“UC Wolfskill can be harvested 12 to 14 days earlier than Chandler and provides consistently light to extra light color,” says UC Davis breeder Chuck Leslie. Photo by Janine Hasey

UC Davis researchers have bred a new walnut variety designed to provide growers a way to harvest earlier and boost the harvest efficiency of California's $1.6 billion walnut industry.

The new “UC Wolfskill” walnut has yield, quality and light color similar to Chandler, which is a late-harvesting walnut and the state's leading variety. UC Wolfskill was bred in 2003 from a cross of Chandler with the Solano walnut. UC Wolfskill combines the color and shell traits of Chandler with the earlier harvest date and kernel fill of Solano.

“The release of UC Wolfskill means growers can spread out their harvest and still have a really high-quality nut that will fetch top-notch prices and provide similar yields,” said Pat J. Brown, breeder and professor with the UC Davis Department of Plant Sciences.

Over 99 percent of the nation's walnuts are grown in California. More than half of the state's bearing acres are the late-harvest Chandler walnuts.

“The California walnut industry needs earlier harvesting walnut varieties to provide efficient use of harvesting, drying and processing equipment,” said breeder Chuck Leslie, with the UC Davis Walnut Improvement Program. “UC Wolfskill can be harvested 12 to 14 days earlier than Chandler and provides consistently light to extra light color.”

Handlers judge the value of a walnut based on its color and how well it halves while processing. In blind quality evaluations by commercial graders, the UC Wolfskill was often not distinguished from Chandler.

UC Wolfskill was originally planted and evaluated at UC Davis, and field trials with growers began in 2011.

“The commitment of our walnut growers, as collaborators, is the foundation that makes this release possible. 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,” said Michelle Connelly, executive director of the California Walnut Board.   

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.

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