Growing the Valley

The pistachio hull is critical for protecting the kernel. Insect pests can’t get through it until it begins to break down. However, it is known that hull integrity can change across years - some years hulls stay intact until harvest, and in other years it begins to break down earlier. Shuxiao Zhang, who used to be a student at UC Davis and is now working as a postdoctoral scholar at Stanford, and Georgia Drakakaki, a professor of plant sciences at UC Davis, decided to look into this. They were able to figure out the processes that led to hull degradation, the different ways degradation occur, and they were able to link in-field conditions to hull split. The Drakakaki lab has been doing extensive research into pistachio fruit development - Phoebe has interviewed the both of them on pistachio shell split in a previous episode. You can sign up for the Rice Production Workshop here. Find out more about upcoming meetings in the San Joaquin Valley (scroll to the bottom) and the Sacramento Valley. The views, thoughts, and opinions expressed are the speaker’s own and do not represent the views, thoughts, and opinions of the University of California. The material and information presented here is for general information purposes only. The "University of California" name and all forms and abbreviations are the property of its owner and its use does not imply endorsement of or opposition to any specific organization, product, or service. Follow us on Twitter! @SacOrchards and @SJVtandv Thank you to the Almond, Pistachio, Prune, and Walnut Boards of California for their kind donations. Thank you to Muriel Gordon for the music.

Phoebe sits down with Elizabeth Fichtner to discuss the biology of pistachio bloom, how it impacts orchard design, and why picking the correct male pollinator is so important. She also goes over the research on artificial pollination of pistachio and why it may only be useful in very specific circumstances. In this episode, Elizabeth mentions that dust can cause parthenocarpy in pistachios; we posted an episode on this a few years ago.

Phoebe and Sam Sandovol Solis discuss the water outlook for 2026. They also discuss some things that everyone can do to maximize water infiltration. If you are interested in finding out more about groundwater recharge, you should check to see if your orchard block has favorable soil textures and is in a good location for it here. More information on applications for recharge can be found here. Phoebe interviewed two researchers in 2025 about the effects of wildfire smoke on orchards, which you may be interested in if 2026 ends up being a bad fire year (fingers crossed this isn’t the case!) Episode transcript Find out more about upcoming meetings in the San Joaquin Valley (scroll to the bottom) and the Sacramento Valley! The views, thoughts, and opinions expressed are the speaker’s own and do not represent the views, thoughts, and opinions of the University of California. The material and information presented here is for general information purposes only. The "University of California" name and all forms and abbreviations are the property of its owner and its use does not imply endorsement of or opposition to any specific organization, product, or service. Follow us on Twitter! @SacOrchards and @SJVtandv Thank you to the Almond, Pistachio, Prune, and Walnut Boards of California for their kind donations. Thank you to Muriel Gordon for the music.

Self-fertile Nonpareil has the potential to be a gamechanger for California almond growers. Both Sierra Gold Nursery (FruitionOne™) and Burchell Nursery (Nonpareil SC+) announced in late 2024 their partnerships with biotech companies to develop a self-fertile Nonpareil. Both nurseries plan to begin delivering these trees to growers in 2027. However, many questions remain. In this episode Tom Burchell owner of Burchell Nursery discusses the development and future for Nonpareil SC+.

Facing tightening SGMA regulations and the specter of future droughts, how should we be designing the almond orchard of the future? On the podcast, Franz Niederholzer discusses his idea of a test almond orchard at the Nickels Soil Lab with different rootstocks provided reduced irrigation treatments from planting onward. Should a grower provide full irrigation to fewer acres, or reduced irrigation to their existing farming footprint?

Environmental bud failure showed up in almonds in a big way in 2025. From a subtle delay of leafing in parts of Nonpareil canopies throughout the Central Valley to some orchards in the northern Sacramento Valley with only half leaf out. This disorder also called leafing failure, severely affected many growers in the northern Sacramento Valley. Dr. Tom Gradziel (UC Davis) gets into the complexities of this disorder, as well as discussing the unusual bloom in 2025.