The response of ‘Monalisa’ apples to high CO2 storage conditions, harvest maturity and 1-MCP treatment

•The response to storage atmosphere of ‘Monalisa’ apple was studied.•Several CO2 partial pressures on ‘Monalisa’ apples were evaluated.•‘Monalisa’ apples are very susceptible to high CO2 injury.•1-MCP has no effect on the susceptibility to high CO2 injury.•Late harvested fruit are more prone to develop physiological disorders. This study aimed to determine the effects of harvest maturity, 1-MCP treatment and storage conditions with high CO2 partial pressures on ‘Monalisa’ apples physicochemical quality and susceptibility to physiological disorders and decay during long-term storage, plus 7 d of shelf life at 22 °C. The study was composed by two experiments. In Experiment 1, fruit were harvested in one growing season (2011) at the same maturity stage and were treated or not treated with 1-MCP (1 µL L-1). In Experiment 2, fruit were harvested in two growing seasons (2019 and 2020), at two maturity stages. In both experiments, all fruit were stored under CA with four CO2 partial pressure (0.5, 1.5, 3.0 and 4.5 kPa) and regular air (RA, standard of comparison) for 6 or 7 months at 0.8 °C, plus 7 d shelf life at 22 °C. CA was very effective on delaying fruit ripening, senescent disorders and decay incidences, regardless of the CO2 partial pressure. However, under CA, ‘Monalisa’ apples were very susceptible to CO2 injury, expressed as dark flesh browning and cavities that were exacerbated with increasing CO2 partial pressures. Therefore, ‘Monalisa’ apples should be stored under CA with CO2 no higher than 0.5 kPa. The response of ‘Monalisa’ apples to high CO2 is more pronounced in late harvested fruit, which were also more prone to develop senescent flesh browning, cracking and rough skin. 1-MCP application had no effect on ‘Monalisa’ apple susceptibility to CO2 damages, while it reduced fruit softening and acidity loss in both RA and CA storages.