A multi-year research project evaluating the use of Dormex in pistachio orchards indicates the material holds value in years with adequate chill accumulation. Research Director at the MARI Agricultural Research Institute, Masood Khezri said the 2022 data showed promise. Dormex helped to support bloom synchronization, a critical factor impacting yield. The research continued in 2023, which was a high chill year compared to the previous low chill observed in 2022.
Khezri explained that they applied Dormex at chill portion (CP) 65 in early February and at CP 70 in mid-February. As part of the trial, both male and female control trees did not receive an application of Dormex and still had proper bloom synchronization. “However, the right timing of Dormex application could further improve it,” said Khezri.
The research results showed that the application of Dormex at CP 70 could extend the bloom window for male trees even further. Khezri explained that it was important to replicate the trial in both low and adequate chill seasons to measure the impact of Dormex under different weather scenarios. They found the optimal bloom window and synchronization between male and female trees was found when Dormex was applied at CP 70. “The other thing is that Dormex at CP 70 increased the yield around 220 pounds per acre,” said Khezri.
Information from the UC Davis Chill Calculator shows that as of January 30, the Durham CIMIS station has logged 54.3 portions under the dynamic model, with 744 hours below 45°F. The station in Manteca has registered 50 portions, with 627 hours. There have been 824 hours in Merced, with 49.2 cumulative portions. In Five Points, there have been 670 chill hours, equating to 48.1 portions. Finally, the CIMIS station in Shafter has registered 45.9 portions, with 678 hours.
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