Cropping and Fruit Quality of Plum (Prunus domestica) Varieties on Different Rootstocks in a Young Orchard

In Hungary, plum cultivation in earlier years was mainly for processing purposes, and a suitable cultivation system and rootstock use had been developed. For this reason, the rootstock usage is rather uniform, with 95–97% of nurseries applying Myrobalan seedlings. Growing plums for the fresh market is much more profitable but it requires hand-picked trees. For small trees that can be picked standing on the ground and for high yields, we need to find rootstocks suited to the Hungarian climate. In our experiment, two types of evaluation were performed: evaluation block A with three varieties on two rootstocks and evaluation block B with two varieties on three rootstocks. The varieties were ‘Topfive’, ‘Toptaste’, ‘Čačanska lepotica’ and ‘Jojo’. The rootstocks were the traditional Myrobalan and the rootstocks worthy of testing in Hungary: St Julien GF655/2, St Julien A, and Fereley. The experiments were carried out in Kecskemét, Hungary, in a dry lowland climate. Evaluations were performed by one- and two-factor analyses of variance, and means were separated by the Duncan test. As a result, we found that in the evaluation block A trees of ‘Toptaste’ showed lower vigour and cumulative yield but higher yield efficiency. The trees on St Julien A proved to be more productive in cropping years and showed higher yield efficiency compared to Myrobalan. In evaluation block B, there was no difference in growth vigour between either varieties or rootstocks. Trees of ‘Toptaste’ showed higher cumulative yield compared to ‘Topfive’. However, the cumulative yield of trees did not show significant differences; the yield efficiency of ‘Topfive’ was highest on Fereley rootstock. Regarding fruit quality parameters, our study showed differences in fruit maturity and varietal characteristics. Considering the intensive orchard system with spindle trees, St. Julian A proved to be a more productive and precocious rootstock compared to Myrobalan seedling, while for ‘Toptaste’ variety the rootstock Fereley showed certain advantages. ‘Topfive’ proved to be unsuitable for our site conditions.