POSTHARVEST PITTING IN NAVEL ORANGES AT NON-CHILLING TEMPERATURE: INFLUENCE OF RELATIVE HUMIDITY

Postharvest pitting and rind staining in Navel oranges at non-chilling temperatures has become an increasing problem in recent years. The disorder is characterised by scattered clusters over the fruit surface that turn brown and dark after several weeks’ storage. The origin of this disorder is still unknown, its incidence is unpredictable, and to date successful postharvest methods have yet to be developed to control it. In some cultivars, as Navelate oranges, affected fruits can be also found attached to the tree. The disorder also occurs on other Citrus species, and it has been reported that waxing may aggravate the disorder by modification of gas exchange (Petracek et al., 1995, 1998). In this study, we have investigated the influence of relative humidity (RH) and its variation during storage of Navel oranges on the development of rind staining and the potential relation with changes in respiration rate, ethylene production and internal gas concentrations.