Severity of scuffing injury of ‘Zesy002’ kiwifruit as influenced by maturity

Kiwifruit (<i>Actinidia chinensis</i> var. chinensis ‘Zesy002’) have a relatively long harvest season, where fruit will change in maturity and hence attributes. Harvest may be followed by a long postharvest storage period. Scuffing is the discolouration of kiwifruit skin in response to an injury. This injury is observed throughout the supply chain to some extent and thus, it is of interest to identify possible reasons that predispose kiwifruit to skin discolouration. In this work, maturity, as influenced by harvest date and estimated by firmness and total soluble solids, was investigated as a potential descriptor of scuffing susceptibility. ‘Zesy002’ kiwifruit were sampled from 11 orchards in New Zealand on three occasions (ISO weeks 12, 18 and 20) during the 2020 harvest season. Upon arrival to the lab, 24 fruit from each grower were non-destructively assessed prior to a deliberately controlled scuffing treatment and subsequently stored for 2 weeks at 0°C, to allow symptom development. Of the at-harvest maturity indicators, firmness was found to be the strongest indicator of scuffing susceptibility and severity of the damage. Further work is required to understand the physical or physiological reasons that cause softer fruit to be more susceptible to scuffing.