Rootstock

From Freepedia

Grafting is a method of plant propagation by which one woody plant is mechanically attached to another so that the two eventually fuse together. This is a very common method of propagating trees. A twig from one tree is grafted onto the stump of a rooted tree. The stump, which already has an established, healthy root system, is called the rootstock. The tree part being grafted onto the rootstock is usually called the scion. The scion is the tree which has the fruiting properties desired by the propagator, and the rootstock is the working part which interacts with the soil to nourish the new fruit tree. After a few years, the tissues of the two parts will have grown together, producing one tree which is genetically two different plants.

The rootstock can be a different species from the scion, but the two must be closely related. A grafting can also be done in stages, with a closely related scion being grafted to the rootstock, and a much less closely related scion being grafted to the first scion. Also, with a serial grafting of several scions one may produce a tree that bears a number of different fruits. The same rootstock absorbs and disperses water to the whole system.

Grapevines are also grafted to rootstocks. Grape growers prefer not to take the risk of purchasing or growing a whole plant, when it is safer to establish a number of healthy rootstocks and then graft vines onto them as they desire. This provides an extra measure of control over the growth of the plant, since the quality and characteristics of the resulting fruit is so important.

It can be hard to match a plant to the soil in a certain field or orchard. Growers want a rootstock which is compatible with the soil; the fruiting characteristics of the scion can be considered later, once the rootstock has proved successful. Rootstocks are studied extensively and sold with a complete guide to their ideal soil and climate. Growers determine the pH, mineral content, nematode population, salinity, water availability, pathogen load, and sandiness of their particular soil, and select a rootstock which is matched to it. Genetic testing is growing more common, and new cultivars of rootstock are always being developed.