rootstock

Rootstock refers to the part of a grafted plant that forms the root system, providing the plant’s root architecture and the environment in which the scion grows. The scion is the upper portion that determines the fruit, flowers, and overall form. For a graft to be successful, the rootstock and scion must be compatible and well joined.

Rootstocks can be seedling or clonal. Seedling rootstocks come from seeds and are genetically variable, while clonal rootstocks are produced vegetatively to preserve specific traits. They influence the mature size and vigor of the tree, as well as tolerance to soil conditions, moisture, temperature, and certain pests or diseases.

Functions and effects of rootstock choice include vigor control (dwarfing, semi-dwarfing, or standard), precocity and yield patterns, tolerance to drought, cold, salinity, and soil types, and resistance to soil-borne pests or diseases. Rootstocks can also affect nutrient uptake, root-zone temperature, and overall tree health. The right match can improve orchard productivity and management, while poor matching can lead to incompatibility or reduced performance.

Common uses by crop vary. In grape production, rootstocks are selected for Phylloxera resistance and soil adaptation, enabling Vitis vinifera to grow in affected soils. In apples, rootstocks are chosen to achieve desired tree size and density, supporting high-density planting and earlier fruiting. In stone fruits, rootstock choice influences vigor, drought tolerance, and soil compatibility, though compatibility with the scion and long-term orchard life must be considered.

Management and limitations include ensuring cambial compatibility, proper grafting technique, and post-graft care. Incompatibility or poor setup can cause graft failure, requiring re-grafting or rootstock renewal.