Articles
EFFECT OF ROOTSTOCKS ON GROWTH OF PLUM CULTIVARS IN A YOUNG ORCHARD
The trees of cultivars ‘Stanley’, ‘Cacanska lepotica’ and ‘Althann’ were planted on following rootstocks: Myrobalan ‘C 162/a’ seedling, vegetatively propagated Marianna ‘GF 8–1’, Myrobalan ‘MY-BO-1’, Myrobalan ‘MY-KL-A’, Sainte Julien ‘GF 655/2’, and Prunus domestica ‘Fehér besztercei’. The plantation is located on a sandy soil with low (1.2 %) humus content, layered on a flooded soil next to the river Danube.
In the soil of the orchard a high pH (7,82) and high calcium content (28 %) were measured.
Spacing of trees is 4.5 x 2.5 m, 5 cm of the rootstock is exposed above soil line.
Trees were trained to spindle system.
Trunk girth, and canopy size were measured every year, from the data trunk cross sectional area, canopy area and volume were calculated.
The paper presents the first four years results of the trial.
Largest trees in trunk cross sectional area, canopy area and canopy volume were produced on Marianna ‘GF 8–1’ and Myrobalan ‘C 162/a’ seedling rootstocks.
Trees on Myrobalan ‘MY-BO-1’ and Myrobalan ‘MY-KL-A’ are medium sized and in comparison to the above rootstocks small tree size was achieved on rootstocks Sainte Julien ‘GF 655/2’, and Prunus domestica ‘Fehér besztercei’. It is worth mentioning that Althanns on ‘MY-KL-A’ produced early yielding dwarf trees.
Early training of spindle trees seems to be easier on medium vigorous or vigorous rootstocks because of their good branching ability.
However, the growth of trees on vigorous rootstocks in the third leaf was too large, more summer pruning is needed to train them to a spindle tree.
Rootstocks producing medium or small tree size seem to be promising for high-density plum orchard.
Yield character of trees on various rootstocks cannot be judged yet, but the flower density and fruit set of trees on Myrobalan ‘MY-BO-1’ and Myrobalan ‘MY-KL-A’ is conspicuous.