Biodynamic preparations 500 and 501 are plant strengthening agents of biodynamic agriculture method, prepared of manure and powdered quartz. The objective of the present study was to determine effects of biodynamic (BD) preparations 500 and 501 on the quality indices and antioxidant compounds content in the tubers of coloured flesh potatoes. The experiment included two factors: potato cultivar and treatment with BD preparations as field sprays. The experiment was carried out in four

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... , in a randomly design. Results showed that application of BD preparations did not influence significantly the contents of dry matter, crude fibre and crude ash in all tested cultivars. Separately used BD preparation 500 increased content of total anthocyanins in tubers of 'Vitelotte' and 'Red Emmalie' and leucoanthocyanins content in 'Blue Congo', but decreased the content of total phenolics in all cultivars. Treatment with BD preparation 501 had significant effect on the contents of total phenolics and total anthocyanins in all cultivars. However, treatment with BD preparation 500 in combination with BD preparation 501 substantially increased the contents of total phenolics and total anthocyanins in all cultivars. Tubers of 'Vitelotte' with dark-purple flesh contained significantly more antioxidant compounds than the lightpurple and red.