Summer Pruning: An Ecological Alternative to Postharvest Calcium Treatment to Improve Storability of High Quality Apple cv. 'Reinette du Canada'

Two strategies, summer pruning and postharvest Ca treatment, were studied in apple (Malus domestica Borkh) cv. 'Reinette du Canada' in order to analyze its effect on the fruit quality during storage. Summer pruning and Ca treatment reduced external and internal bitter-pits; so after 180 days of storage, both treatments decreased external bitter-pit by 10.0% and 16.7%, respectively. Summer pruning influenced color, firmness, total soluble solids and titratable acidity (TA) of fruit during storage, whereas Ca treatment only affected firmness and TA. Fruit from pruned trees had significant lower K and Mg than those from unpruned trees and Ca treatment increased Ca content. Orchard management, by means of summer pruning, combined with Ca postharvest application would be useful to prevent losses due to bitter-pit during storage in commercial orchards. However, in organic orchards, summer pruning would be the ecological alternative to decrease bitter-pit incidence during storage in high quality apple cv. 'Reinette du Canada'. K/Ca ratio, on the peel at harvest, turned out to be the best parameter to correlate with external and internal bitter-pits during storage; so this ratio would be useful to predict bitter-pit on long-term storage.