Improvement of kiwifruit resistance to Botrytis storage rot by curing.

In trials assessing the control of the most important postharvest disease of kiwifruit, i.e., storage rot (Botrytis cinerea ), fruits were cured at temperatures between 5 and 30°C with 95-98% RH for 24-96 h before being stored at 0°C. At 15°C, the fruits were also cured in the presence of low RH (40-45%). Pedicel scars, where most infections start, and artificial wounds were inoculated with the pathogen. All the tested curing temperatures induced a significant decrease in storage rot of fruits inoculated either on artificial wounds or on pedicel scars, the lowest number of infections being obtained in the fruits cured at 15°C. The percentage of infected fruits was significantly lower in fruits cured for 48 h rather than for 24 h; longer curing durations did not induce any further significant reduction of infection. Lower infections were obtained in high RH-cured fruits with respect to low RH. The enzyme phenylalanine ammonia-lyase (PAL) was assayed in the tissues close to the artificial wounds and pedicel scars of cured and uncured kiwifruit. PAL activity as a whole showed increasing values in cured fruits where under blue light a certain accumulation of phenolics was evident.