Фолијарна примена азота и калцијума у функцији квалитета и чувања кајсије | Foliar application of nitrogen and calcium in the function of quality and storage of apricot

Apricot is among stone fruits with widespread utilization, both as fresh and in various processed products. Application of contemporary knowledge, selection of cultivars adapted to external conditions accompanied with selection and application of appropriate pre-harvest treatments are just some among the measures which are used in intensive apricot production. With a proper combination of preand post-harvest treatments, intensive production represents a solid basis for production of high quality fruits, less susceptible to deterioration in postharvest period, with the aim of extension of fruit shelf life. The objective of this research was to investigate the effect of foliar application of nitrogen and calcium on the quality and shelf life of apricot cultivars created by the Faculty of Agriculture in Novi Sad, in dependence of application of investigated post-harvest treatments. Investigation of combinations of treatments and their interactions was conducted in order to obtain results based on which guidelines for the selection of the most suitable cultivars and optimal combination of pre- and post-harvest treatments for achievement of optimal quality and shelf life of apricot are obtained. Another objective is to enable extension of the season of availability of fresh, high quality level apricots on the market through the application of appropriate combination of both, pre- and postharvest treatments. Application of urea and calcium nitrate foliar treatments affected the increase in fruit weight in most of the cultivars tested. The application of foliar treatments resulted in a smaller ratio of stone in Buda and Novosadska kasnocvetna cultivars. Better fruit firmness, as a significant parameter for the manipulation and storage of fruits, was achieved by foliar treatments for the NS-6 cultivar, while for Buda cultivar, applied treatments did not exhibit significant effect on fruit firmness improvement. Urea-based foliar treatments resulted in a higher soluble solids content in the Buda cultivar, while the same effect in the case of NS-4 cultivar were obtained when calcium nitrate was used. Apricot fruit color properties, as well as the content of total acids, polyphenols and carotenoids are dependent on the cultivar, production season, concentration of nutrients and number of applied treatments. The objective of the application of foliar treatments was to reduce the production of ethylene, which was achieved in the case of Novosadska kasnocvetna and NS-6 cultivars. The intensity of respiration depends on many factors such as cultivar, weight loss, and temperature. The loss of fruit firmness and change in fruit color parameters during the storage of apricot fruits were also observed in our study. The use of modified atmosphere packaging (MAP) resulted in a reduction in weight loss after 15 and 15+3 days of storage for all cultivars independently of applied pre-harvest treatment. The application of MAP and 1 – methylcyclopropene (1-MCP) treatments reduced the production of ethylene in all cultivars except Novosadska rodna. The downside of MAP treatments is that they result in a higher level of internal browning of fruits.The sensory evaluation of fruits revealed that the application of pre- and post-harvest treatments did not affect the presence of offflavour and guminess, while certain treatments and cultivars exhibited improvement regarding sweetness and aroma.