Evaluation of plum cultivars grafted on ‘Wangenheim Prune’ rootstock in the northeast of Poland

The study was conducted in the years 2007-2012 at the Didactic and Experimental Station of the University of Warmia and Mazury in Olsztyn in order to select plum cultivars suitable for growing on ‘Wangenheim Prune’ rootstock in northeastern Poland. The study encompassed the following plum cultivars: ‘Herman’, ‘Čačanska Rana’, ‘Dąbrowicka Prune’, ‘Promis’, ‘Elena’ ‘Tolar’, ‘Bluefre’, ‘Top’, ‘President’ and ‘Valor’. The measurements taken included: trunk growth, yield, weight of one fruit, size of fruit, the content of dry matter, ascorbic acid, total and simple sugars and organic acids. We found that the ‘Valor’ and ‘Herman’ trees grew the best and ‘Top’ grew the most poorly. The highest yields were gathered from the ‘President’, ‘Valor’ and ‘Bluefre’ trees. ‘Bluefre’ had the largest fruit size. The highest content of dry matter was found in the fruit of ‘Tolar’, ‘Valor’ and ‘Promis’. The fruit of ‘Bluefre’, ‘Tolar’ and ‘Top’ had the highest concentration of ascorbic acid. The highest content of total sugars and simple sugars was detected in the fruit of ‘Tolar’, while the highest concentrations of organic acids were found in the fruit of ‘Čačanska Rana’, ‘Dąbrowicka Prune’ and ‘Top’. ‘Promis’, ‘Herman’, ‘Valor’, ‘Top’ and ‘Tolar’ had the highest sugar/acid indexes.