Determination of fruit chemical contents of two plum cultivars grafted on four rootstocks

The study was aimed at assessing chemical composition of fruits of plum cultivars ʻCacanska Lepoticaʼ and ʻJojoʼ grafted on four rootstocks with different mechanisms of resistance to Plum pox virus (PPV): sensitivity, ʻWavitʼ and ʻWeiwaʼ and hypersensitivity, ‘Docera 6’ and ‘Dospina 235’. The cultivar significantly influenced on content of sugars and organic acids, with the highest values in cultivar ʻJojoʼ. The highest content of sucrose, sorbitol and total sugars were found in ʻWeiwaʼ, and all individual and total acids were higher in fruits from trees grafted on ʻWavitʼ. On the one hand ‘Cacanska Lepotica’ had a high content of malic acid, but on the other hand a low content of citric and fumaric acids, regardless of the rootstock. The most abundant phenolic compounds, phenolic acids and flavanols, were shown to be at the highest level in the combinations ʻCacanska Lepoticaʼ/ʻDocera 6ʼ and ʻJojoʼ/ʻWavitʼ, whereas less abundant phenolic compounds, flavonols and anthocyanins, were the highest in the combinations ʻCacanska Lepoticaʼ/ʻWavitʼ and ʻJojoʼ/ʻWeiwaʼ. In order to improve nutritive fruit quality and the technology of growing, as well as to delay the spread of PPV, rootstocks ʻWavitʼ and ʻWeiwaʼ can be recommended for further promotion in modern plum plantations.