Calcium is very important for the quality of fruit, especially apples. The goal of this study has been to determine the effect of calcium on the quality of apples and mineral nutrient concentration in different apple tree varieties. The determination of quality parameters can help to postpone fruit ripening. Golden Delicious, Pink Lady, Jonabres and Red Delicious apple varieties were used in this study. CaCl2 was applied in a 0.5% solution sprayed twice, 15 days apart, after full bloom. Plant ion concentrations (Ca, K, Mg, Fe, Cu, Zn, Mn of the leaf tissue) were determined as well as the following quality parameters of apples: fruit weight, diameter, height, soluble solid content, pH, titratable acidity, fruit skin colour, firmness measured. Calcium application increased the Ca concentration in leaves and improved the quality parameters compared to the control conditions. Two applications of  0.5% CaCl2 spray at a fifteen-day interval after full bloom were sufficient, and the foliar application of calcium was needed even when no deficiency symptoms were observed. While fruit weight, width and height increased, the respiration rate and ethylene production decreased. Variety differences were significant in this study. Jonabres and Golden Delicious apple varieties were affected more by the Ca treatments than the other varieties.

27.1.2022