Various grafting techniques or methods of grafting are practiced in plants. Their applicability depends on many factors such as the skill and preference of the grafter, percentage grafting success desired, the time required to achieve complete graft union, the portion and size of the plant to be grafted, and the purpose of grafting.
Familiarity with the different methods is important in plant propagation and other uses. But grafting is not easy. It needs plenty of practice and experience to become one who can be considered as an expert. It is not easy either to gauge how fast the grafting operation can be done. But for mango, there are some who are capable of producing 400-500 grafts in one day through manual cleft grafting with over 80% successful union.
The Grafting Techniques Methods
Approach Grafting – a grafting technique in which two separate plants are made to unite by tightly pressing the cut side surfaces of the stems. Preferably, one or both plants are potted. As soon as the parts have united, the upper portion of the rootstock stem is severed above the point of graft union and the lower portion of the scion is removed below the graft union. There are various forms of approach grafting.
Bark Grafting – a plant grafting technique in which small scions are inserted into a large rootstock in between the bark and the wood. The rootstock is decapitated and a downward linear cut is made through the bark starting from the stub. The scion is prepared with a long slanting cut from one side toward its base and a short cut on the opposite side which forms the base into a wedge.
The bark is then lifted at both sides of the cut and the prepared scion is inserted between the bark and wood in such a manner that the long cut on the scion is pressed against the wood on the rootstock. Both scion and barks are nailed to the rootstock stem or bound tightly. In another technique, only one side of the bark is lifted and the scion is inserted.
In yet another technique, two downward, parallel cuts are made from the stub of the rootstock which are connected with a horizontal cut near the bottom end. The bark is removed, leaving a small flap of bark at the bottom. The scion is then inserted under the flap of bark and the long cut pressed to the wood of the rootstock. The scion, as well as the flap of bark, are nailed to the rootstock or bound tightly.
Bridge Grafting – a grafting technique used to repair damaged bark on a trunk by attaching scions that will connect the live barks below and above the injured patch, serving as live bridges. The scions are attached in close interval, their number depending on the width of the injured bark.
The procedure in preparing the tree is similar to that in inarching, except that two slots on the trunk of the tree are made, one below and another above the injured bark. At each tip of the slots, a flap of bark is retained.
The scions to be used are slightly longer than the distance from the end of the top slot and the end of the bottom slot. Each is prepared with a long, slanting cut at each end, both of which are at the same side of the stem. A short, slanting cut is then made at the side opposite the first cut so that both ends form a wedge. The wedged ends of each of the scions are then inserted under the flaps of bark at the upper and bottom slots in a manner that each curves slightly outward. The scions are nailed through the flaps of bark or bound tightly.
Cleft or Wedge Grafting – a grafting technique in which a rootstock is first decapitated at the portion of the stem where there is active growth, followed by a downward cut (the cleft) through the center of the stem starting from the stub. The scion is prepared with a slanting cut at one side at the base and a similar cut at the opposite side so that the base is wedge- or V-shaped (about 4-6 cm long in pencil-size scions). The base of the scion is inserted into the cleft at the top of the decapitated rootstock. Two small scions may be inserted, one at each side of the rootstock to ensure cambial contact.
Inarching – as in approach grafting, both rootstock and scion plants are self sustaining, both are cut on one side, and the cut surfaces are pressed together. But in inarching, the top of the rootstock does not extend above the point of the graft union.
The scion plant, for example a tree on which additional trunk is to be joined, is prepared by two adjacent, long vertical cuts on the bark. It is followed by two horizontal cuts that connect the vertical cuts, one at the bottom and another just below the top. The rectangular piece of bark is then removed with a short flap of bark still remaining at the top.
The rootstock, or seedling that is to become the additional trunk, is prepared by removing the top portion of the shoot, then making a deep cut through the wood at the side adjacent to the scion. The length of this cut from the decapitated portion of the stem matches the cut on the scion tree. Opposite to this cut and at the tip, a short cut is made to form it into the shape of a wedge.
The cut surface on the seedling stem is pressed tightly to the cut surface on the tree with the wedged tip covered by the flap of bark. The seedling is then nailed to the tree or secured tightly by a tying material.
Saddle Grafting - this is similar to cleft grafting except that the wedge is on the rootstock and the cleft is at the base of the scion. The rootstock is first decapitated and a slanting cut is made from one side of the stem toward the center of stub and a similar cut is made at the opposite side. A slit (the cleft) is made by pressing a knife at the base of the scion. The base of the scion is then pushed into the rootstock in such a manner that the wedged end of the rootstock is inserted into the cleft of the scion.
Saw-Kerf or Notch Grafting - a thick rootstock is first decapitated. An inward cut is then made almost to the center of the stub with the use of a thin-bladed, fine-toothed saw. Three saw cuts that are distributed around the stub are usually made. With the use of a sharp, round-bladed knife, the cuts are widened to fit the scion. The basal end of the scion is cut to a long wedge, in a manner that it tapers downward and with the outer edge slightly thicker than the inside edge.
Side Grafting – a grafting technique in which the scion is inserted into the side of the rootstock which is generally larger in diameter than the scion. There are several variations of side grafting.
Splice Grafting - a technique of grafting plants that is similar to the first cut in whip or tonque grafting, that is, a long slanting cut is made on the rootstock stem (about 30 degrees from vertical) with a matching cut at the scion base. The surfaces of both cuts are pressed together and bound tightly. This technique is applied in grafting three-week old tomato (as scion) on four-week old eggplant rootstocks, with the difference that the cut surfaces are fitted through a small tubing.
Whip or Tonque Grafting – a grafting technique in which the rootstock is decapitated with a long slanted cut at the portion of the stem where there is active growth and a similar cut is made at the scion base, just like in splice grafting; a second cut is made partly across each slanted cut starting about one-third of the length of the cut from the tip towards the base of the cut. As a result, they form “tonques” which hook the scion firmly onto the rootstock. This grafting technique favors more cambial contact and is intended for small materials. Preferably, both scion and rootstock have identical sizes. As in the other types of grafting techniques, the scions are pressed to the rootstock with the buds pointing outward.
ABELLANOSA AL, PAVA HM. 1987. Introduction to Crop Science. CMU, Musuan, Bukidnon: Publications Office. 245 p.
HARTMANN HT, KESTER DE. 1975. Plant Propagation: Principles and Practices. 3rd ed. New Jersey: Prentice Hall Inc. 662 p.
(Ben G. Bareja May 2011)