Chuck Leslie and Pat J. Brown, UC Davis Walnut Improvement Program, UC Davis Dept. of Plant Sciences

The UC Davis Walnut Breeding Program has recently released a new walnut variety, ‘UC Wolfskill’.

‘UC Wolfskill’ harvests earlier than ‘Chandler’, ‘Howard’, or ‘Tulare’. Harvest timing is similar to ‘Solano’ with better kernel color, and a thinner shell. Trees yield abundantly at maturity. The smooth-shelled nuts are similar to ‘Chandler’, with an attractive appearance and solid seals.

Figure 1. ‘UC Wolfskill’ nuts at hullsplit (photo by J. Hasey).

Data from more than a decade of evaluation across seven locations show that ‘UC Wolfskill’ kernels are slightly larger, and nuts are consistently better-filled than Chandler trees of the same age, with excellent, Chandler-like color. In multiple years of blind kernel evaluations provided by a major commercial walnut processor, ‘UC Wolfskill’ nuts have consistently been misidentified as ‘Chandler’, suggesting that their commercial value will be comparable.

Figure 2. Nuts and kernels of ‘UC Wolfskill’.

‘UC Wolfskill’ is the result from a 2003 cross between ‘Chandler’ and ‘Solano’. Leafing, flowering, and harvest dates are similar to ‘Solano’, and kernel quality and color are similar to ‘Chandler’. Given the earlier leaf-out, blight management similar to other early varieties may be necessary depending on local weather conditions. ‘Chandler’, ‘Howard’, or ‘Tulare’ are all suitable pollenizers for ‘UC Wolfskill’, which offers growers an early harvest option with ‘Chandler’ nut quality attributes.

Figure 3. Unpruned, unheaded, 5th-leaf ‘UC Wolfskill’ tree (photo by J. Hasey).

‘UC Wolfskill’ is now commercially available to California growers and can be ordered from any licensed nursery. You can learn more about the attributes of other recent releases and industry standards here.