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Ongoing project

Pistachio productivity improvement program (PS17003)

Key research provider: Pistachio Growers’ Association

What’s it all about?

Beginning in July 2018, this investment supports improvements in the cultivation of pistachios and the uptake of new and changing production practices through research, development and extension activities.

It supports the role and activities of a pistachio researcher who, in conjunction with other research associates, is tasked with undertaking ongoing field research that builds on the outcomes of earlier project Maintaining and expanding the technical development of the Australian pistachio industry (PS14000), which was funded by industry contributions through the then Horticulture Australia Limited.

Goals of the work include…

  • Improving yields, through a better understanding of orchard management issues
  • Benchmarking and reporting on quality and yield information to growers
  • Assisting in disseminating information to growers, and in the adoption of R&D
  • Supporting an increase in pistachio plantings
  • Exploring new development areas for pistachio research
  • Responding to any changing environmental and seasonal issues that may arise.

  • 2021/22 Chill Mitigation survey commenced – the survey is analysing different growing methods which were undertaken by growers in the Winter 2021 season due to varied chill unit rates among growing regions. Analysis is being undertaken as to whether these methods impact physiological events such as budburst and flowering.
  • 2021/22 Oil and Polymer trial – Trials have commenced to see if oil-polymer application can enhance pistachio yield and quality.
  • 2021/22 Bud opening and flowering study – bud bursting and flowering is being observed in different aged trees.
  • 2021/22 Pistachio shoot die back study commenced – research is being undertaken to investigate and identify the cause of pistachio branch dieback
  • Orchard visits and meetings with growers were also undertaken in SA whereby growers discussed their experience, management practices any issues they encountered with pistachio cultivation.
  • Three Chill Hour newsletters were distributed in July, August and September 2021 alerting growers to predicted chill hours across major production regions. Access all Chill newsletters on the industry website.

Over the past 12 months, the Pistachio Research Field Officer has undertaken industry-based research, development and extension activities in support of growers and the sector. This includes:

  • Expanded polymer shoot dipping trials with the collection and presentation of this year’s data, and commencement of second year trials
  • Early results were reported, and Season 2 activities implemented, for several sub-programs, including the young Kerman yield trial and the zinc absorption and translocation trial
  • Participation in several events and programs to expand knowledge and research networks
  • Engagement and communication about the benefits of changing production practices with growers, advisors and industry via email, newsletters and participation in meetings and events.


Visit the Pistachio Growers Association website for more information.

Read the Chill Newsletters, designed to share important seasonal information and alerts with growers in a timely way:

Since July 2018, this project has been supporting improvements in the cultivation of pistachios and the uptake of new and changing production practices through research, development, and extension activities.

Polymer trials continued

Following the 2018/19 scoping trial using polymers on selected orchard trees, it was agreed to extend the trial using a larger number of trees. These will be undertaken in a block trial and specific shoot trials in the laboratory facilities at CMV Farms, plus in research trees at the Irymple Research Station.

New sub-programs commenced

A range of additional trial projects were discussed and finalised with Pistachio R&D committee members. Trials were commenced in September 2019 as new sub-programs within the broader project including investigations to:

  • Enhance chill accumulation by using polymer in pistachio trees
  • Improve zinc absorption and translocation by using Zircon, with data on zinc content before and after treatments from within the leaves and soil to be assessed at the end of the trial
  • Assess the possibility to increase yield of young Kerman (related to bud abscission). This trial is focused on trying to understand the underlying causes of low yield of young Kerman trees (6-11 years).
  • Study the nut quality from four different male tree pollen.

Work on all trials continues with information to be shared with industry as results become available.


You can read more about the project teams results in this presentation given at the 2019 Pistachio Grower Industry Association’s Symposium held in Mildura.

Also, this presentation about managing young trees and the zinc research given to the Pistachio Information and Technology Group in November 2019.

You can also learn more on the Pistachio Growers’ Association website.

Data on the 2019 pistachio harvest has been collated and provided to individual growers as benchmarking reports.

Pistachios are extremely sensitive to lack of cold over winter, with lack of chill resulting in uneven and late harvest. To assist growers with this year’s crop, researchers used temperature data from the Bureau of Meteorology to develop a chill report for various growing areas up to June 2019. The report includes steps for growers to undertake so that they can boost yield should lack of chill be a prediction for the next season.

The research team prepared and completed a pilot trial to see if polymer application on orchard trees modified bud temperatures and assisted with yield. The trial began in August 2018 to test if lower temperatures in the last half of August result in lower blanks at harvest, as well as to ensure no ill effects on tree health from the polymer. Cooling polymer applications did increase nut set, and in one of the trial conditions it decreased the number of closed nuts.

In addition to providing support for the use of polymer, the small-scale trial indicated that nut set can be influenced by localised heat accumulation over winter. The effect is more pronounced in marginal chill districts or in low chill years. This is in line with similar observations in high chill lines of apples, cherries, nectarines and peaches. An extended trial using a larger number of trees will be the next step.

The work program going forward has been agreed upon and work has commenced on sub-projects including…

  • Collecting data for a trial of Kerman
  • Collecting information on pollen and nut quality
  • Establishing data on Australian male trees including assessing pollen from each of the varieties
  • A trial with the aim of increasing absorption of zinc.


Read the Chill Newsletter June 2019 to find out more about chill accumulation this season.

In September 2018, Dr Subhashini Abeysinghe was appointed to the role of Pistachio Researcher under this investment. Dr Abeysinghe, known as Subha, is an experienced field-based researcher with a PhD in agriculture from Charles Sturt University, a Masters in environment studies from the University of Melbourne, and many years of experience working with horticultural crops.

Subha was introduced to pistachio growers in November 2018, presenting at the spring Tech Group meetings facilitated by the project Technology transfer for pistachio growers (PS17002), and can be reached at

Research activities in the project have so far included the establishment of small trial looking at the use of polymers. The work is intended to see if applying polymers on pistachio trees can lower bud temperatures, and so assist with yield – also scoping the proposition that lower temperatures in the last half of August result in lower blanks at harvest.

Initial results have shown some benefits, but final results won’t be available until nuts are harvested and checked in 2019.

Other activities in the project have included…

  • Reviewing previous research and scoping industry needs, to develop and begin implementing new industry research initiatives to benefit growers, under priority themes. These will grow to include mitigating the lack of chill, research into blanks, chemical work, variety studies, pruning trials and more.

  • Communicating with growers, including through the channels of PS17002 and via farm visits, to support beneficial changes in production practices and to collect samples and information to feed into research.

At the time of writing this update, a pistachio researcher was set to be appointed – look out for further information in industry channels as it becomes available. It is expected that areas of research for the investment and potential sub-projects will include research into blanks, boron application, chill hours, the use of the modified central leader tree structure and more.