Influence of four different dwarfing rootstocks on phenolic acids and anthocyanin composition of sweet cherry ( Prunus avium L) cvs 'Kordia' and 'Regina'

Influence of four different dwarfing rootstocks: 'Gisela 5', 'Gisela 6', 'PHL-C' and 'PiKU1' on the amount of polyphenols (total phenols, total and individual anthocyanins and individual hydroxycinnamic acids) of sweet cherry cultivars 'Kordia' and 'Regina' was researched as well as correlations between polyphenols and colorimetrically measured fruit skin colour. Total phenols (TP) and total anthocyanins (TA) were determined by spectroscopic methods, while individual anthocyanins and hydroxycinnamic were quantified and identified by high performance liquid chromatography (HPLC). 'Gisela 6' and 'PiKU1' had the strongest influence on the TP content of both cultivars. The main hydroxycinnamic acid identified was p-coumaric acid (p-CA) which content was influenced by cultivar, vegetation year and interaction of cultivar* rootstock* year. Content of p-CA varied the most on rootstock 'Gisela 5' for both cultivars, with its lowest amount obtained in 2013 and the highest in 2014 in comparison to other rootstocks. The largest difference in TA content in cultivar* rootstock interaction was identified in 'Gisela 6'. Substantial difference in correlation pattern between cvs. 'Kordia' and 'Regina' lead to the conclusion that values L* and b* are better TA indicators rather than values a* and Hue.