S16 - Session O2 - Uniformity of fruit maturity and quality from different wood types within dwarfed kiwifruit canopies

Authors: Adam Friend *, Aljaz Medic, Ben van Hooijdonk, Matthew Punter, Anna Tattersall, Jess Bryne, Jason Johnston

Kiwifruit lack visual cues of harvest maturity, leading to strip-harvesting of the crop. This results in variability of fruit quality present on the vine at harvest entering the supply chain. Grading out low-quality fruit adds an expense to packing, and modern grading systems can struggle to perform reliable and rapid assessments of fruit maturity to remove fruit with undesirable quality traits. We segregated fruit from four Actinidia chinensis var. chinensis 'Zesy002' vines, each grafted to either a low-, medium- or high-vigour rootstock, according to the wood type from which the shoots bearing fruit originated. Wood types included low-, medium- and high-vigour canes, spurs, or perennial structures. The shape and weight of all fruit were assessed on an automated sorting system, while laboratory assessments of fruit dry matter concentration, flesh colour, flesh firmness, and total soluble solids content were made on a randomly selected 20-fruit sample for each wood type per vine. The proportion of different wood types of scion canopies grafted to different vigour rootstocks were not different. Subtle differences in the uniformity of both fruit maturity and quality existed from shoots from various wood types within a canopy. For example, fruit distribution curves were skewed towards flat fruit, while fruit originating from shoots growing off higher-vigour wood, were also skewed towards flat fruit. Consequently, the adoption of low-vigour orchard systems or the selection of low-vigour wood types during pruning could reduce the number of flat fruit entering the supply chain.