A SPECIAL GROWERS’ REPORT OF AG ALERT ® CALIFORNIA Trees & Vines
Trials focus on 30 almond varieties for performance By Vicky Boyd At a field day in Modesto, University of California Cooperative Extension pomology adviser emeritus Roger Duncan walks attendees through 30 almond varieties involved in the fourth-generation Stanislaus County regional variety trial. The event featured almond kernel samples, inset, of some of the varieties involved in the trials.
rootstock commonly used in the area. At Chico, for example, trees are on Krymsk 86, which is known for its strong anchorage to keep trees from being blown over in high winds. The Modesto and Bakersfield trials are on high-vigor Hansen 536 rootstock. As it has for nearly 50 years, UCCE manages the experiments, with the almond board providing funding. Each trial is farmed by the producer hosting it. Since Duncan joined UCCE more than three decades ago, he said he’s noticed a shift toward self-fertile varieties in the trials and in commercial orchards—and he understands the attraction. “With self-fertile varieties, they tend to be more consistent,” Duncan said. “Of course, you don’t need as many bees. They just produce a more consistent yield in years when the bees don’t want to fly.” Of the 30 current trial entries, about three-fourths are self-fertile. Also included are Nonpareil, a self-incompatible variety considered the industry gold standard for nut quality, along with pollinizers Butte, Padre, Aldrich and Bennett-Hickman. As part of the trial, UC has nine experimental selections from university almond and stone fruit breeder Tom Gradziel. Unlike private breeding programs that are pressed to see a return on investment, he said the university is able to examine longer-term issues. One is self-fertility. Currently, the three commercial self-fertile varieties were bred using the naturally self-fertile cultivar Tuono from Europe. But heavy reliance on this See ALMONDS, Page 9
Borrowing a page from school classrooms, the University of California held three show- and-tell sessions last month to share its latest regional almond variety trials with the industry. Comprising 30 named varieties and numbered experimental selections from public and private breeding programs, the trials test tree performance under commercial farming conditions. UC experts will evaluate each variety annually for yield, bloom, harvest timing and possible pest issues. They and the Almond Board of California also will rate kernels for size, shape, color, flavor and other traits coveted by processors. Even if a variety has a reasonably good showing in the trials, Roger Duncan, UC Cooperative Extension pomology adviser emeritus in Stanislaus County, recommended growers approach it cautiously. “We never know unless something’s been out there for 20 years how it’s going to do,” he said. Bennett-Hickman is a good example. The pollinizer variety initially looked promising but in recent years has been plagued by what some call environmental leafing failure. Duarte Nursery, which marketed Bennett-Hickman, has since pulled back on promoting it. Planted in September 2022 and early 2023, the trials are the fourth generation of regional almond variety evaluations the UC has undertaken. In addition to Modesto, the UC has one in Bakersfield and one at the California State University, Chico, farm. While all the trials contain the same 30 varieties, trees at each site are grafted onto a
8 Ag Alert June 18, 2025
Powered by FlippingBook