Growth reduction effect and fruit quality of plum cultivars on rootstocks 'Krymsk^®1' and 'Krymsk^®2' after five years of cultivation

The influence of rootstocks ‘Krymsk^®1’ (Prunus tomentosa × Prunus cerasifera) and ‘Krymsk^®2’ (Prunus incana × Prunus tomentosa) on growth (trunk cross-sectional area − TCSA, tree canopy volume) and fruit quality parameters (fruit weight, height, firmness and soluble solids content − SSC) was compared with rootstock ‘Mr.S. 2/5’ (Prunus cerasifera × Prunus spinosa). Tree vigour and fruit quality of four plum cultivars (‘Čačanska Lepotica’, ‘Elena’, ‘Hanita’ and ‘Tophit’) were evaluated in Holovousy (Czech Republic) in the experimental plum orchard after five growing seasons. Statistical analyses were carried out by Statistica software (version 12, Stat Soft). The growth (TCSA and tree crown volume) was significantly lower on ‘Krymsk^®1’ and ‘Krymsk^®2’ in comparison with ‘Mr.S. 2/5’. No significant differences in fruit weight were recorded (‘Krymsk^®1’ – 26.5 g; ‘Krymsk^®2’ – 24.8 g and ‘Mr.S. 2/5’ – 25.2 g). Fruit firmness was significantly higher on rootstock ‘Mr.S. 2/5’ (index 73.7) in comparison with ‘Krymsk^®1’ (index 70.0) and ‘Krymsk^®2’ (index 71.0). SSC was the highest in ‘Krymsk^®2’ (19.8 °Brix) and lower in ‘Krymsk^®1’ and ‘MRS 2/5’ (19.3 °Brix). Some differences were recorded between the cultivars. Tree size-controlling rootstocks for plums provide a great boost in production efficiency suitable for growing conditions in central Europe.