Term (also grafting, copulation, varaltet Pelzen) for the artificial, vegetative propagation of woody plants. This is most commonly used for rose and fruit varieties. In principle, it is a transplantation of a plant part (scion) onto the root part of another plant (rootstock). The process can also be referred to as cloning, because genetically completely identical new plants are created from the original plants.
Grafting in ancient times
This practice was already known in ancient times, especially for fruit and olive varieties. Cato the Elder (234-149 BC) mentioned in his work "De agri cultura" (also "De re rustica" - On Rural Affairs) that this was also common for grapevines. The purpose was, of course, different from today: to preserve the special characteristics of certain plants when they were endangered by a poor or disease-prone root system, unsatisfactory vigour or incompatibility with the soil.
Lower part (root system): 1 = Grafting point, 2 = lateral roots, 3 = root stem, 4 = foot roots
Upper part (scion): 1 = one-year-old wood, 2 = biennial wood, 3 = cordon of old wood, 4 = trunk of old wood, 5 = watershoots of one-year-old wood, 6 = grafting site
Reason for grafting - phylloxera
The cause of the worldwide widespread grafting of grapevines was phylloxera, which was introduced from America in the middle of the 19th century. In the complex life cycle of the pest, the leaves above ground and/or (much more dangerous) the roots below ground are attacked. The vines react as a defence by forming galls (leaves) or growths (roots), which the phylloxera uses as food.
The growths on the roots are called nodosities (especially on young, non-lignified roots) and tuberosities (especially on old roots). Some of the American grapevine species are resistant to varying degrees. Phylloxera-resistant species form little or no growths on the roots.
Difference between Vitis vinifera and Vitis cinerea
The picture on the left shows a microscopic section of an older Vitis vinifera with a tuberosity formed by phylloxera infection with a hole-like depression extending far into the interior of the root (1). The picture on the right shows a microscopic section through a tuberosity on a Vitis cinerea, which has formed a cork tissue after the phylloxera attack (3). The picture in the centre shows a winged female phylloxera (Sexuparae) and a male phylloxera (Aptera).
Problem solution
After numerous failed attempts with some absurd ideas (such as directing electricity into the soil), a solution was finally found. Scions of European vines were grafted onto the rootstocks of selected American vines. The American species Vitis berlandieri (high lime tolerance, phylloxera-resistant at the root), Vitis rupestris, Vitis riparia and the particularly phylloxera-resistant Vitis cinerea are resistant.
As early as the end of the 19th century, crosses were therefore made between various American species, but also with the European Vitis vinifera, and rootstocks were selected from these. Ideally, they are not only resistant to phylloxera and nematodes (threadworms), but are also suitable for a wide variety of soil types and harmonise with the growth characteristics of the respective scion (upper part).
The character of the new vine is determined solely by the grafted noble variety, as the genetic material of the scion is not mixed with that of the rootstock, but remains unchanged. The rootstock, which is foreign to the species or variety, "only" serves to anchor it at the growing site, to absorb water and nutrients from the soil and to defend against underground vine blight.
This is in contrast to the...
