A Gift that Grows
Pistachio Research for a Changing Climate
Pistachios power a nearly $3 billion industry in California, but the future of this crop is being threatened by rising temperatures, disappearing winter fog and limited water. Weather pattern changes are especially impacting the southern San Joaquin Valley, where most pistachios are grown and growers are being forced to adapt or risk decline.
At UC Davis, researchers are meeting this challenge by planting the seeds for a more resilient pistachio industry. With a generous gift from pistachio farmer and philanthropist Rod Stiefvater, efforts are underway to develop new cultivars and hardier rootstocks that can thrive in hotter, drier conditions.
Stiefvater, owner of Oro Vista Farms in Kern County, has given more than $335,000, along with dedicated land and farming support, to help researchers evaluate new varieties under real-world growing conditions. This gift pairs funding with field access which enables researchers to test pistachios exactly in the location where they’ll need to succeed.
“I view it as a way to give back to the industry that has provided for my financial success in ways that I never dreamed possible,” said Stiefvater.
Testing cultivars and rootstocks
At the heart of this work are Professor of Cooperative Extension Louise Ferguson, as well as Associate Professor Patrick J. Brown and Associate Professor of Cooperative Extension Giulia Marino, who are leading the Pistachio Breeding Program in the Department of Plant Sciences. They’re focused on identifying which cultivars and rootstocks perform best under environmental stressors like heat, drought and various levels of salinity. Their work also preserves and builds on valuable plant material developed through decades of scientific research.
Postdoctoral researchers, along with undergraduate and graduate students, are working alongside renowned faculty and expert Cooperative Extension specialists to use tissue culture techniques that efficiently propagate new pistachio cultivars. This approach allows the team to produce uniform plants for controlled testing, supporting faster and more precise evaluation of traits important to long-term crop resilience.
“The very first limitation to planting a tree crop is climate and we can’t fool Mother Nature,” said Ferguson. “The only solution is developing new cultivars. The impact of this research will be cultivars that can tolerate lower chill and more saline soils – determining not only yield and quality, but whether a tree can survive in the challenging conditions growers are already facing.”
The gift also launched a new fund to support varietal research in California’s top pistachio-growing counties, allowing this work to continue growing and evolving for years to come.
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Louise Ferguson
Cooperative Extension Specialist, Plant Sciences