Root system development of container-grown apple nursery trees as affected by rootstock, container type, and substrate composition

The quality of planting material is a key factor determining the successful establishment and long-term productivity of i n tensive orchards. In container nursery systems, plant development largely depends on the interaction between rootstock gen o type, container design, and substrate composition, which influence root system architecture, nutrient and water uptake, and biomass accumulation. The aim of this study was to determine the effect of rootstock, container type, and substrate compos i tion on the formation of belowground and aboveground biomass of two-year-old apple nursery trees grown in container cu l ture. The experiment included two rootstocks differing in vigor, two container types, and three substrate variants with different physical properties. Plant growth was evaluated at the end of the growing season based on root system biomass and abov e ground biomass formation. The results showed that rootstock genotype significantly affected plant biomass formation. Trees grafted onto the more vigorous rootstock formed greater total biomass compared with those on the dwarfing rootstock, with differences reaching 25–35% depending on growing conditions. Container type also influenced plant development: containers with improved root-zone aeration stimulated the formation of a more branched fibrous root system and increased root mass by 15–20% compared with standard containers. Substrate composition affected the balance between root and shoot development. Substrates with higher air-filled porosity promoted more intensive root growth, whereas mixtures with higher water-holding capacity stimulated the formation of aboveground biomass. The study demonstrates that the interaction between rootstock, container type, and substrate composition plays an important role in optimizing container nursery technologies and improving the quality of planting material for intensive fruit production systems.