What are the common bud grafting methods for citrus? How are they done?
Citrus grafting methods can be broadly divided into three types: bud grafting, side grafting and cut grafting. In the warmer southern subtropical zone, spring cut grafting is mostly used, while in the mid-subtropical zone and further north, autumn bud grafting or re-grafting is mostly used. Citrus bud grafting includes "T" bud grafting and inverted "⊥" bud grafting, both methods are used in various regions, and the suitable grafting period...
Citrus grafting methods can be broadly divided into three types: bud grafting, side grafting and cut grafting. In the warmer southern subtropical zone, spring cut grafting is mostly used, while in the mid-subtropical zone and further north, autumn bud grafting or re-grafting is mostly used.
Citrus bud grafting includes "T" bud grafting and inverted "⊥" bud grafting, both methods are used in various regions, and the suitable grafting period is from mid-August to mid-October. At this time the scion is already fully mature. The rootstock sap flow is also very vigorous, the bark peels easily, and the grafting survival rate is high.
At a point 15 cm above the ground on the rootstock, choose a smooth, straight spot, make a horizontal cut, with the depth limited to cutting through the bark layer, then from the center of the horizontal cut use the tip of the knife to make a vertical slit, with the cut about 2 cm long, and use the knife tip to pry open the bark layer at the vertical cut on the rootstock to both sides.
When cutting the bud, generally place the branch along (or upside down) in the left hand, clamp it with the thumb and index finger, hold the knife with the right thumb and index finger, start cutting the bud piece from 0.5 cm below the bud, stop cutting at 0.7 cm above the bud, withdraw the blade, and cut at a 45° angle at the stopping point, to obtain a boat-shaped bud piece, with wood attached below the bud point, and the bud 1.2 cm long. A standard bud piece should be centered on the bud and leaf stalk, with the upper part above the bud and the lower part below the bud accounting for 2/5 and 3/5 of the bud piece respectively, and the cut surface of the bud piece is required to be smooth and hairless.
When inserting the bud, hold the grafted bud with the right hand, insert the lower end of the bud piece into the horizontal cut on the rootstock, push downward with force, so that the whole bud piece is inserted smoothly into the vertical cut, until the upper end of the bud piece fits tightly with the "T"-shaped horizontal cut on the rootstock. Then use a 1 cm wide, 20-25 cm long film strip, first tie the grafted bud tightly to fix it, with the left side 1/4 long and the right side 3/4 long, then wrap the right film strip downward 2 turns, then upward 2-3 turns, and tie a knot 1-1.5 cm above the grafted bud opening to secure it tightly.
The "T" bud grafting and inverted "⊥" bud grafting differ in the direction of the knife when cutting the bud, the opening of the cut on the rootstock and the entry point for inserting the bud are exactly opposite, while the other operations are completely the same, and there is no difference in the grafting survival rate.