In the course of a 3-year study the natural occurrence of storage diseases in ambient air storage with
1 to 2°C was evaluated on samples of 30 cultivars and advanced selections that were harvested from orchards with and without the use of fungicide treatments. Based upon the frequency of occurrence, bitter rot and grey mould were the most common diseases in this study followed by blue mould and brown rot. Fungicide treatments applied in the orchard with integrated plant protection reduced total fruit rotting with different cultivars two to four times. Significant losses caused by rotting usually took place in the last quarter of the normal storage life of each cultivar, but in the case of samples treated with fungicides it was mostly during the last month. Cultivars Angold, Gala, Florina, Melodie and Meteor proved to be partially resistant to the storage diseases, but the smallest shares of rotted fruits were recorded on apples of Zuzana andMelrose. Still, five advanced selections proved not to be so affected by fruit rotting asMelrose and Zuzana, from which HL 237 and HL 390 were the most remarkable. The majority of selections with resistance to storage diseases as well as Zuzana cv. contain Glockenapfel cv. in their pedigree.