Effect of rootstocks on growth and yield efficiency of plum cultivars

With the aim of selection rootstocks for high density plum orchard and adaptable to local soil and climate conditions in Middle-Hungary, trial was established in 1994. The trees of cultivars 'Stanley', 'Čačanska lepotica' and 'Althan's Gage' were planted on following rootstocks: Myrobalan 'C 162/a' seedling, vegetatively propagated Marianna 'GF 8-1', Myrobalan 'MY-BO-1', Myrobalan 'MY-KL-A', 'St 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 Danube river. In the soil of the orchard a high pH (7,82) and high calcium content (15-20 %) 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. 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 'St Julien' 'GF 655/2', and Prunus domestica 'Fehér besztercei'. It is worth mentioning that 'Althan’s Gage' on 'MY-KL-A' produced early yielding dwarf trees and later incompatibility symptoms. 'Stanley' produced highest yield efficiency on vigorous Marianna GF 8-1, medium yield efficiency was achieved on Myrobalan C 162/a seedling, MY-BO-1, MY-KL-A, and 'St Julien' GF 655/2, low efficiency was on semi-dwarf 'Fehér beszterce'. There was no significant difference found in the fruit weight on trees planted on different rootstocks. Best producer trees of 'Čačanska lepotica' were also on Marianna GF 8-1, MY-KL-A while 'St Julien' GF 655 reduced yield efficiency. Significant larger average fruit weight was found on trees on 'St Julien' GF 655/2 and MY-KL-A rootstocks in comparison to Myrobalan seedling C162/a. Best yield efficiency and fruit weight of 'Althan's Gage' was found on 'St Julien' GF 655/2, medium on Marianna GF 8-1 and Myrobalan seedling C 162/a, while the MY-KL-A produced low.