California Chill Report: Helping Pistachio Yield in Low Chill Conditions

Brian German Chill Hour Report, News from our Sponsors

Pistachio Yield

Research Director at the MARI Agricultural Research Institute, Masood Khezri has been working on a project related to bloom synchronization in pistachio orchards. Part of the multi-year trial has included evaluating materials to potentially overcome challenges related to a lack of chill accumulation.  

“I can say the effect of Dormex was significant on yield increase when you compare it with untreated control trees,” Khezri explained. “It is interesting, in one location which was a low chill location, we had the highest yield by spraying Dormex compared to oil-sprayed trees and nontreated control trees.”

The first year of the multi-year commercial trial was conducted on Kerman/Peters pistachio blocks in multiple locations in Tulare County. At one of the trial locations, the pistachio yield from Kerman trees that received a Dormex application was more than 800 pounds per acre more than the control trees.

“In the first year, we sprayed Dormex at different chill portions. In a good chill location, we got the highest yield at chill portion 65,” said Khezri. “At the right timing, it increased the yield significantly. So, timing is very critical, and I suggest that growers track the chill portion from their local weather stations and their nearest CIMIS stations to spray Dormex at the right time. I also encourage them to follow the label instructions.”

Information from the UC Davis Chill Calculator shows that as of February 1, the Durham CIMIS station has logged 63 portions under the dynamic model, with 1,081 hours below 45°F. The station in Manteca has registered 60.2 portions, with 988 hours. There have been 1,130 hours in Merced, with 62 cumulative portions. In Five Points, there have been 1,068 chill hours, equating to 58.5 portions. Finally, the CIMIS station in Shafter has registered 57.6 portions, with 1,054 hours.

Listen to the latest chill report below.