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National tree crop intensification program (AS18000) – Citrus

Key research provider: NSW Department of Primary Industries
Publication date: Monday, May 3, 2021

What's it all about?

This investment is part of a collaborative R&D program of tree crop-specific projects established to deliver step-change orchard system intensification knowledge, understanding and technical advancements to the citrus industry.

The project is delivering new knowledge for citrus growers that supports the need to change traditional growing systems to increase yields and orchard profits. The project will deliver:

  • Increased productivity and profitability for the citrus industry through intensification and innovation.
  • New, robust information and tools available to growers to make improved production decisions.
  • Development of adoptable advanced production systems that can be deployed by growers within the life of the project.
  • Generation of new information and resources available to citrus growers that define plant morphology suitable for intensive and productive cropping and harvesting
  • New, robust information and tools available to citrus growers to provide greater confidence in their current systems, improve the profitability of their current systems and/or make moves towards a more intensified system with a clearer understanding of the options and implications for their farms.

Across three key areas, the project team will…


  • Conduct a literature review on current understanding and emerging technologies.
  • Compare the growth and productivity of a wide range of citrus varieties to identify architectural features limiting crop production and to aid the development of a crop ideotype best suited to high-density intensifications.
  • Develop of draft integrated small trees information package, including videos that outline the variation between a range of citrus varieties with regards to tree architecture and crop load.


  • Establish pruning trials on four commercial properties to explore the use of extreme canopy manipulation on mature commercial high-density plantings.
  • Hold pruning field days to communicate findings to the citrus industry
  • Conduct an economic analysis and create a financial tool for use by citrus growers.


  • Evaluate the presence/persistence of inoculated viroids across multiple existing research blocks and commercial operations and examine the lasting impact on canopy size and shape, shoot length, trunk circumference, fruit size, weight, and yield.
  • Compare different dwarfing viroids for their impact on canopy size and productivity.
  • Investigate the effect of inoculation with CVd III has had on a navel orange on a research station.
  • Explore the efficacy of inoculation and dwarfing of CVd III in a mandarin and lemon and/or lime on a research station.
  • Create a draft information package on the use, choices, and implications of using viroids.

Results will be disseminated through a suite of communication materials such as case studies drawing on grower and industry experience, videos and factsheets on canopy management for high-density orchards, and industry articles in the Australian Citrus News magazine and Citrus News e-newsletter.