Effects of Auxin-Induced Parthenocarpy on Ethylene Production and Postharvest Quality Attributes of Zucchini Fruit

The current production of zucchini squash (Cucurbita pepo) under greenhouse conditions requires the induction of parthenocarpy by using synthetic auxins. We report the effects of preharvest auxin treatments on ethylene production, weight loss, firmness, and chilling injury of commercial zucchini squash fruit of 'Natura', 'Elena', 'Celeste' and 'Millenium' during their postharvest storage at 4 and 20 degrees C for 14 days. Ethylene production was highly induced in all the fruit after storage at 4 degrees C for 7 days, but decreased significantly after 14 days of storage at the same temperature. At 20 degrees C, the production of ethylene, however, remained low throughout storage. The postharvest quality of the fruit, including chilling injuries were very dependent on the genotype and storage temperature, but were also affected by auxin treatments. The external treatments with auxins induced the production of ethylene in postharvest fruits, favoured the loss of fruit weight and firmness, and promoted chilling injury. Therefore, although preharvest treatments with synthetic auxins are effective to increase the production and size of zucchini fruits, they can adversely affect different postharvest fruit quality attributes.