The influence of the rootstock on tree vigor and productivity of plum cultivars

Abstract

The influence of three clonal rootstocks ('Pixy', 'Fereley', and 'St. Julien A') and one seedling rootstock ('Myrobalan') on tree vigor and productivity of three table plums cultivars ('Èaèanska Rana', 'Èaèanska Lepotica', and 'Èaèanska Najbolja') was examined in the region of Belgrade over a period of three years (2013-2015). Trunk crosssectional area, number, and length and weight of shoots removed during summer pruning were used as vigor indicators, while fruit set, yield tree-1, and cumulative yield efficiency were used as productivity indicators. Rootstocks exhibited a significant influence on tree vigor and productivity of the tested cultivars. The lowest values of the vigor indicators were found on 'Pixy' rootstock for all cultivars, and the highest values were found on 'Myrobalan' seedling rootstock. Based on the results obtained, 'Pixy' can be classified as a dwarf rootstock, 'Fereley' and 'St. Julien A' as medium vigorous rootstocks, and 'Myrobalan' as a vigorous rootstock. The fruit set was highest on 'Fereley' rootstock (on average 19.1% for all cultivars), while on the other three rootstocks it had lower values ranging from 16.4-17.1%. The highest yield tree-1 was obtained on 'Fereley' rootstock (on average 20.33 kg for all cultivars), then on 'St. Julien A' (18.50 kg) and 'Pixy' (16.09 kg), while the lowest yield was obtained on 'Myrobalan' seedling rootstock (15.62 kg). Cumulative yield efficiency was also the highest on the rootstock 'Fereley' (on average 1.05 kg cm-2 for all cultivars), and the lowest on 'Myrobalan' seedling rootstock (0.71 kg cm-2).