Ongoing regional testing in Butte, Stanislaus and Madera counties continue to produce promising results for multiple experimental almond varieties.

UCD 18-20, an experimental pollinizer from UC Davis, and Booth from Burchell Nursery seem to be performing closest to Nonpareil compared to other varieties on the test plots (Table 1.) UCCE Pomology Farm Advisor Roger Duncan, who has been monitoring the test plots since 2014 along with UCCE’s Phoebe Gordon and Luke Milliron and UC Davis’ Bruce Lampinen, provided insight into the varieties’ success.

“Yield is probably one of the major things,” Duncan said in reference to what has stood out.

Cumulative 3rd-leaf to 7th-leaf yield data averaged from the three Central Valley test plots show UCD 18-20 and Booth at 10,940 pounds and 10,197 pounds, respectively, compared to the standard Nonpareil at 11,638 pounds.

USDA self-fertiles Yorizane and Y117-91-03 have also stood out in terms of yield, according to Duncan in UC ANR’s The Scoop newsletter, boasting a cumulative average of 10,140 pounds and 9,742 pounds, respectively. Of course, yield isn’t the only quality being assessed as ‘promising’ in these plots.

“When they’re promising, they appear to be compatible with Nonpareil (good bloom overlap), yielding well, and you don’t see any major drawbacks,” Duncan said. Hull split, harvest time, kernel quality and insect/disease susceptibility are also being assessed.

Bloom time, Duncan said, isn’t necessarily important for self-fertiles since they would theoretically be planted in a solid block in a commercial setting, but harvest time is. “We now have a lot of orchards that harvest at about the same time,” he said. “Nonpareil and Independence harvest at pretty much the same time. Shasta, which is a real up-and-coming self-fertile variety, also harvests at the same time. So, we would really like to see varieties that don’t harvest in that Nonpareil window.”

Varieties that help spread out harvest time are being increasingly sought after to relieve pressure on the processor side. Duncan said that early harvesting varieties are not common in almonds, but noted that Y117-91-03 is harvesting about one week before Nonpareil. Others, he said, are harvesting two to four weeks after Nonpareil, a good sign for increasing varietal options.

Duncan said in The Scoop that some varieties, including UCD 18-20, have a high percentage of doubles as well as other issues that might limit their adoption. For this reason, plantings of new varieties in commercial orchards are discouraged by UC until longer-term studies are conducted.

More information on experimental variety performance up to this point can be obtained by contacting Roger Duncan at raduncan@ucdavis.edu or (209) 525-6800.