Fruit and Nut Research and Information Center: Decision-Making Tools

A screenshot of the FNRIC Almond Rootstock Comparison Tool ( Data for up to three rootstocks can be compared side by side.

The Fruit and Nut Research and Information Center (FNRIC), part of the UC Davis Plant Sciences department, is a hub of information for fruit and nut growers, researchers and industry members. Apart from sharing general knowledge and updates on research projects, FNRIC provides practical decision-making tools tailored to support California growers. These tools are built on research conducted by scientists from UC Davis and UC ANR and are designed to help growers make informed management decisions.

One of the most widely used decision-making tools provided by FNRIC is the chilling accumulation model. Proper development of many fruits and nuts relies on sufficient chilling temperatures during winter. If these trees don’t receive enough chilling hours, buds may struggle to break dormancy, leading to physiological issues like delayed bloom, reduced fruit set and diminished fruit quality.

Traditionally, growers and industry professionals have monitored the local accumulation of chilling hours from November onward. This tracking helps gauge orchard management needs and make comparisons with previous years’ weather conditions and crop loads. The FNRIC chilling accumulation model can be found at

A screenshot of the FNRIC chill accumulation model ( Chill hours below 45 degrees F as collected by the Davis CIMIS station are graphed. Data from the 2023-24 season are compared to data from the 2021-22 and 2022-23 seasons.

In addition to the chilling accumulation model, the FNRIC offers other weather-related models to assist growers in decision-making. Two examples are the almond hull split prediction model and the pistachio bloom forecast. These models use current and historical weather data to forecast the timing of crucial physiological stages, aiding growers in planning management and harvest.

Beyond weather-related models, FNRIC offers a range of crucial decision-making tools, including a nitrogen and potassium prediction model for pistachio growers. The model incorporates pre-season recommendations and individual user data from mid-season leaf samples to allow growers to make informed decisions about the timing and quantity of fertilizer applications.

A screenshot of the FNRIC Nitrogen and Potassium Prediction Model for Pistachio ( Pre-season recommended distribution percentages for nitrogen and potassium are graphed for April/May, June, July and August.

One of the newest decision-making tools offered by FNRIC is the almond rootstock database and comparison tool. This tool was developed as an aid for growers in making informed decisions about which rootstocks to choose for their orchards. By allowing them to filter options based on critical factors relevant to their planting site, the tool simplifies the decision-making process. Whether growers prioritize anchorage to enhance stability or need to address concerns related to phytophthora, this tool equips them with essential information to guide their planting decisions.

Join us for the 2024 Principles of Fruit and Nut Tree Growth, Cropping and Management course. Course topics include best practices for pruning, irrigation, fertilization, pest management, harvesting and much more. Learn from UC pomology experts through lectures, lab exercises and field demonstrations during our five-day class, followed by an optional four-day field trip. The field tour will take you through fruit and nut breeding, growing and processing facilities in the Sacramento and San Joaquin valleys. The first week of the course will be held March 11-15, 2024 at Foundation Plant Sciences and the Teaching Orchards on the UC Davis campus. The following week, the field tour will be held for an additional fee on March 18-21, 2024. Scholarship applications close in mid-January. For more information, scan the QR code or email

A screenshot of the FNRIC Almond Rootstock Database ( Rootstock data pages are listed alphabetically and can be filtered by qualities of interest.

Visit to explore these and other tools and stay informed about the latest research from UC Davis and UC ANR. The website provides access to several resources, and for any further questions or concerns, you can contact the Fruit and Nut Research and Information Center at