The Effect of Organic Production on the Sugar and Organic Acid Concentration in Different Sour Cherry Cultivars

Sour cherry is one of the most popular stone fruits in Poland. In the organic production system of sour cherries, no artificial pesticides and fertilizers are allowed, which is one of the organic production requirements increasingly appreciated by producers and consumers. The taste of fruits is created by the sugar and organic acid content and their ratio. Vitamin C is known for its health-promoting properties. The aim of the present study was to analyze and compare the concentrations of vitamin C, sugars, and organic acids and their profiles in organic vs. conventional sour cherry fruits representing different cultivars, in a three-year experiment. In the presented experiment, four sour cherry cultivars, ‘Kelleris’ 16, ‘Oblacińska’, ‘Pandy 103’, and ‘Debreceni Bötermö’, were cultivated in two horticultural systems, organic and conventional, and the content of sugars and organic acids was analyzed in the fruit with HPLC methods. Organically cultivated sour cherry fruits were characterized by significantly higher concentrations of sugars and vitamin C only in the first year of the experiment, when the mean concentrations of fructose, glucose, and sucrose in these fruits reached 4.15 g/100 g F.W., 0.37 g/100 g F.W., and 0.27 g/100 g F.W., respectively, and the concentration of vitamin C reached 17.28 mg/100 g F.W. In the two subsequent years, conventional cherries were more abundant in these compounds. Among the tested sour cherry cultivars, ‘Oblačińska’ performed the best in terms of sugar content. The mean value for total sugars for ‘Oblačińska’ cv. was 5.53 g/100 g F.W. In the case of vitamin C, the highest levels (av. 28.13 mg/100 g F.W.) were noted in the fruits of ‘Pandy 103’ cv. The strong year-to-year variability underscores the need for multi-year experiments and, where possible, multi-site trials, to disentangle cultivar × system × environment interactions. Because the quality of sour cherry for fresh consumption and for processing depends mostly on sugar content, for organic production, ‘Oblačińska’ cv. is strongly recommended.