This document discusses potential uses of phenocams in horticultural studies. It notes that understanding tree growth cycles is important for properly timing management operations in fruit production. While temperate/deciduous trees have relatively straightforward single growth flushes per year, evergreen subtropical trees can have multiple vegetative and reproductive growth flushes per year, with significant variation between seasons and trees. Key metrics identified for monitoring avocado growth include the timing of growth flushes and the proportion of trees involved in each flush.

1. Possible uses for phenocam in
horticultural studies
Dr Grant Thorp, Plant & Food Research Australia, Brisbane
Presentation to ACEAS Phenocam Workshop, North Stradbroke Island, Queensland 11 March 2014

2. New Zealand-based science company providing research for the fruit,
vegetable, cropping and seafood industries.
Crown Research Institute: amalgamation between HortResearch and Crop &
Food Research
Over 900 employees: 650 research staff, 15 sites in New Zealand, plus sites in
USA and Australia
Plant & Food Research

3. » Correct timing of management operations is fundamental to successful
fruit production
» These operations are often timed to meet the period of highest “demand”
which are reflected in the growth cycles of trees
» Understanding the “extent” of each growth cycle, i.e. the size of the
demand is also important to understanding the accumulation of reserves
in plants and future cropping cycles
Phenology = tree growth cycles

4. Few challenges with temperate/deciduous trees
» Working with temperate and/or deciduous trees with a single
major growth flush each year is relatively straightforward
» Key metrics: time of flowering, time of leaf area development
(emergence and senescence) and fruit development (skin colour)

5. Challenge is with evergreen and subtropical trees
» Evergreen tropical and subtropical trees can produce multiple flushes of
vegetative and reproductive growth each year
» Significant variation between seasons and between trees

6. Key metrics for avocado:
1. Timing of vegetative and reproductive growth flushes
2. Proportion of the tree/orchard involved in each growth flush (ON
and OFF cropping trees)

7. www.plantandfood.com.au
Grant Thorp@plantandfood.com.au
Thank you