Growth Characteristics of Five Plum Varieties on Six Different Rootstocks Grown in Containers at Different Irrigation Levels

Abstract

In contrast to other European countries, the nurseries in Hungary mainly use Myrobalan seedlings as rootstock for plum trees; no experience with other rootstocks is available yet. The aim of our research was to gather experience and recommend rootstocks to growers that are adapted to the climatic conditions and can be used in high-density intensive orchards. In the experiment, six rootstocks (Myrobalan seedlings, ‘St. Julien GF655/2’, ‘St. Julien A’, ‘Fereley’, ‘Wangenheim’ and ‘WaVit’) and five varieties (‘Topper’, ‘Toptaste’, ‘Topfive’, ‘Čačanska lepotica’ and ‘Jojo’) were tested. The experimental plantation was established in Kecskemét, in the lowland region of Hungary, which is characterised by low humus content and dry climatic conditions. The trees received two different irrigation doses from 2012 onwards, one for each half of the trees (six trees) of a combination. The first irrigation dose was 2 L and the second was 4 L per hour. Trees with the highest trunk cross-sectional area (TCSA) and canopy volume were ‘Topper’, ‘Toptaste’ and ‘Topfive’ on the ‘Fereley’ rootstock, but this rootstock showed lower survival, with only 33–50% of trees surviving the 2× dose irrigation. The average TCSA values of the rootstocks showed that ‘Wangenheim’ and ‘WaVit’ rootstocks resulted in too poor growth. In contrast, the Myrobalan seedling (Sdlg) and ‘St. Julien GF655/2’ provided strong growth to the trees based on the TCSA and canopy volume data. The results of the analysis of shoot growth showed that irrigation did not significantly affect shoot length, except for ‘Jojo’. The plum trees developed fruit trees typical of the cultivars after fruiting, with little influence of the rootstocks. ‘Topper’ and ‘Čačanska lepotica’ were dominated by bunched and bunched shoots, while ‘Topfive’ was dominated by short shoots and ‘Toptaste’ developed the highest proportion of long shoots.