Weather Conditions during Specific Apple Phenological Stages Influence Fruit Quality at Harvest and in Storage

Interannual variability in apple fruit quality at harvest and in storage is often associated with weather conditions during specific phenological stages prior to harvest. A number of bioclimatic models have been developed and implemented in a computer weather system to help apple producers of Eastern Canada in their storage and marketing strategies. Previous studies showed that apple fruit firmness is one of the main attributes indicating fruit quality at harvest. Rainfall from 61 to 90 days from bloom (DFB) and air temperature from 31 to 60 DFB explained 39% and 12%, respectively, of ‘McIntosh’ apple firmness variation at harvest time. Weather conditions prior to harvest also influence the incidence of many storage disorders. Low temperatures and high rainfall from 0 to 30 DFB explained 20% and 13%, respectively, of the variation in soft scald incidence in ‘Honeycrisp’ apples. Low temperatures and low solar radiations from 31 to 90 DFB were associated with higher vascular browning incidence in ‘McIntosh’ and ‘Ariane’ apples. Low temperatures and high rainfall from 91 DFB to harvest explained 36% and 13%, respectively, of the variation in soggy breakdown incidence in ‘Honeycrisp’ apples, while high temperatures during this period were associated with superficial scald incidence in ‘Cortland’ apples. Recent evaluations of internal browning and core browning incidences in ‘Empire’ and ‘McIntosh’ apples revealed that ‘Empire’ apples are more sensitive to these disorders than ‘McIntosh’. Even though many of these storage disorders are part of a group called “Low temperature disorders (LTD)”, characterized by browning of internal apple flesh and/or vascular bundles, each of them seems not only to be cultivar specific but also to respond differently to weather conditions at specific phenological periods prior to harvest. Weather based predictions of apple firmness at harvest and risks of physiological disorders before storage are quite useful tools for apple producers in their marketing and storage strategies in order to provide high quality apples to their consumers.