Susceptibility of 'Lisbon' and 'Eureka' lemons to chilling injury

Abstract

‘Eureka’ and ‘Lisbon’ lemons (Citrus limon L.) from the Burnett region in Queensland were stored for 14, 28 or 42 days at 1˚C followed by 7 days at 20˚C to compare their relative susceptibility to chilling injury. The potential effect of cultivar on injury development was examined by harvesting fruit from trees subjected to the same growing conditions to minimise all other variability. Injury appeared in both cultivars after storage at 1˚C for 14 days and 7 days at 20˚C. The incidence of commercially unacceptable chilling injury (moderate and severe) was significantly higher in Lisbon than Eureka fruit after all storage treatments, except for 42 days at 1˚C plus 7 days at20˚C. Eureka and Lisbon lemons had similar respiration rates at 20˚C, but respiration of Lisbon following storage at 1˚C for 14, 28 and 42 days was significantly higher than that of Eureka. Storage at 1˚C for 14 days resulted in elevated respiration in both cultivars, with a peak occurring during the first 24 h. After 28 days at 1˚C, peak respiration increased to 51 mg/kg.h for Lisbon and 34 mg/kg.h for Eureka lemons. Respiration increased significantly with longer storage periods, consistent with extensive chilling injury. It is suggested that the lack of commercial success of cold-treated Queensland-grown Eureka lemons is not because they are more sensitive to chilling injury than Lisbon lemons.