Effect of Summer Pruning and Calcium Spray on Extending Postharvest Life of Kiwifruit cv.  Hayward'

Fruits softening and weight loss during cool storage are the major limiting factors of postharvest life in ‘Hayward’ kiwifruit. In this study, effect of summer pruning at two times, 2 days or 15 days after petal fall, alone or in combination with %1 calcium chloride spray on fruit storage quality of ‘Hayward’ kiwifruit was investigated. Calcium was applied at 90 days after petal fall with 15 days intervals at four times. The harvested fruits were stored at cool storage at 1ºC and 90% relative humidity for 3 months. The results showed that fruits harvested from the pruned vines and treatment with calcium had significantly higher dry matter and calcium contents, but lower magnesium and K/Ca, N/Ca, K+Mg/Ca and N+K/Ca ratio as compared to control. These fruits showed higher flesh firmness, vitamin C content and titratable acidity, but lower weight loss and respiration rate. Furthermore, there was a positive correlation between fruit calcium content and dry matter at harvest time with fruit firmness and vitamin C at the end of storage. However, negative correlations were observed between fruit calcium with weight loss and magnesium content. Overall, summer pruning and calcium application could maintain postharvest quality of ‘Hayward’ kiwifruit by improving mineral elements balance and increasing fruit dry matter.