Innovative rootstocks for apple crops

20-24 November 2017 | Presented by Nicola Dallabetta, FEM, Italy | Future Orchards® Southern Loop

Nicola Dallabetta reviews international apple-rootstock development and the characteristics sought in new rootstocks for modern orchard systems. The presentation draws on FEM research in Trentino, where rootstocks are evaluated alongside training systems, tree density, pruning methods, orchard management and fruit quality.

The ideal rootstock is described as more than a dwarfing tool. Desired traits include precocity, productivity, a useful branch habit, a strong root system, adaptation to different soils and tolerance or resistance to important biotic and abiotic stresses. The presentation specifically highlights apple replant disease, fire blight, Phytophthora root and crown rots, woolly apple aphid, cold and drought.

Dallabetta also places rootstocks in the context of orchard design. Dwarfing material similar to M9 suits high-density systems, while semi-dwarfing material can have a role in multi-leader systems. Rootstock performance is shown as an interaction between genotype, soil, cultivar, climate and orchard management rather than a fixed characteristic.

For Australian growers, the presentation provides a framework for assessing new rootstocks: look beyond tree size and consider precocity, productivity, resilience, compatibility with the intended canopy system and the conditions of the specific orchard site.