Sour cherry is one of the most important fruit crops in Poland and cultivar is an important factor in its cultivation. The experiment was conducted in a commercial family orchard in a year characterized by a warm and wet spring and also by a very hot and dry summer. Fruit yields harvested from well fertilized 19-years old ‘Kelleris 16’, ‘Nefris’ and ‘Łutówka’ trees grafted on Mahaleb cherry and protected against pests using integrated plant protection system were medium high and of good quality, however productivity index of a tree was low. The fruits attained high weight and diameter and contained big amounts of sugars, vit. C, anthocyanins and flavonoids and medium amount of phenolic acids. Among anthocyanins the most important were cyanidin 3-glucosyl-rutinoside and cyanidin 3-rutinoside. Antioxidant activity of fruits measured as percent of DPPH inhibition was high and similar among compared cultivars. Łutówka was the most productive cultivar of medium leaf and fruit size and with fruits of highest vit. C and flavonoids content and lowest total sugars and monosaccharides content. The least productive cultivar was Nefris, though its fruits were the biggest and contained dry matter, soluble solids, anthocyanins and phenolic acids in the highest amounts of all and vit. C at the lowest level of all. Kelleris 16 was the medium productive cultivar characterized by widest leaf blades and smallest fruits. Content of total sugars and monosaccharides in its fruits was the highest and content of anthocyanins and phenolic acids was the lowest. Residues of dodine and thiacloprid determined in the fruits immediately after harvest were much lower than the permissible residue maximum level.

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