GAFTING and Budding are methods of propagating fruit trees, and the simple process of grafting, with the not at all difficult operation of budding, must be introduced into the scheme of work on the school fruit plot.
The possibilities of grafting are numerous, but in the main they may be stated as aiming at the increasing and improving of varieties of fruit trees. For this purpose ripened shoots of a season's growth are selected ; these are known as the scions. The rooted stem to which the scion is affixed is called the stock. The only necessary conditions are:-(1) That the scion shall be a ripened young shoot. (2) That the stock shall be well rooted. (3) That the stock and scion shall belong to the same generic order-and finally that the operator shall possess a certain amount of skill.
There are many forms of grafting, and of these, whip grafting is the most common. It is only possible when the stock and scion are of nearly the same thickness. When the stock is much thicker than the scion, crown grafting is resorted to; thus badly cankered apple trees may be crown grafted in order to improve the growth.
The object in all grafting operations is to bring the cambium tissue layer of the scion to fit exactly with the corresponding layer of the stock. Therefore it is essential that the cuts shall be prepared very carefully.
In whip grafting, a long sloping cut is made through the scion and the stock. A second cut is made in each and a wedge-shaped portion removed from the stock, and the same process is carried out with the scion. The tongue, thus formed in the scion, is fitted into the stock and the graft is firmly tied with bast or raffia and grafting wax or clay is carefully placed round it so that air is excluded. The operation is clearly shown by the diagram in school plot. However, it is interesting as an experiment in grafting. The scions are prepared by cutting the bases into wedge shapes and these are placed into slits made in the stock. The whole graft is held firmly together by bast or raffia, and clay or grafting wax is placed over it. This is removed when the growth commences in the scions.
Fig. 70 .crown grafting.
This is of value in extensive fruit growing, but will hardly find general acceptance in the Fig. 69.
In all kinds of grafting the selection of the scion is of the greatest importance. Healthy, strong shoots must be chosen, and these may be preserved after cutting by placing them in a moist soil in a shaded station. The grafting is carried out in spring, just as the sap is rising in the stock, and while the scions are still dormant.
Fig. 69. whip grafting.
A.-First cut made on stock. B.- First cut made on scion. C.- Second cut forming a wedge-shaped tongue. D.-Second cut on scion. E.-Graft completed and bound with bast or raffia ; finally air is excluded by means of clay, or wax, as indicated by dotted lines.