California Chill Report: Facilitating Bloom Synchronization to Boost Yields

Brian German Chill Hour Report, News from our Sponsors

Bloom Synchronization

Bloom synchronization in pistachio orchards is an important component of maximizing the potential for pollination. Research Director at the MARI Agricultural Research Institute, Masood Khezri has been looking at pistachio bloom and chill accumulation. In working with Dormex, Khezri explained the research has demonstrated positive bloom responses with appropriate applications.

“In the first year of our research trial, we found out that male and female pistachio trees respond to Dormex differently. It directly depends on the spray timing,” Khezri explained. “Very early spray of Dormex can release female Kerman from dormancy, but it is not effective on male Peters. But the right spray timing of Dormex can properly synchronize male and female bloom and actually boost the yield.”

In the trials, the largest yields were observed where bloom synchronization was most consistent. A treatment applied in the latter half of February was the most effective approach in the research. Khezri noted that the project will continue. As pistachios are an alternate bearing crop, there are considerations as to how that could impact production results in the research. “This year we’re going to continue to investigate the efficacy of Dormex on male and female bloom synchrony and yield. And also, to see if Dormex may be used to produce more consistent yields which could benefit growers in the entire industry,” said Khezri.

Information from the UC Davis Chill Calculator shows that as of February 6, the Shafter CIMIS station has logged 60.4 portions under the dynamic model, with 1,098 hours below 45°F. The station in Five Points has registered 60.7 portions, with 1,111 hours. There have been 1,186 hours in Merced, with 64.7 cumulative portions. In Manteca, there have been 1,027 chill hours, equating to 64.3 portions. Finally, the CIMIS station in Durham has registered 66.7 portions, with 1,123 hours.

Listen to the latest chill report below.