Grafting leafy scions onto the lopped-off tender terminals of rootstocks and placing the grafted plants under intermittent mist until healed, has proven to be a very useful method of grafting the mamey (Pouteria sapota), black sapote (Diospyros digyna jacq.,) caimito (Chrysophyllum cainito L.), jackfruit (Artocarpus hetorophyllus Lam.). and other difficult-to-graft fruit trees. Cutting-grafts of fig (Ficus carica L.) treated in the same manner also proved to be an efficient grafting technique.
MATERIALS AND METHOD
Scions are taken with fully developed, but not senescent, leaves. Terminal buds are preferred. About 2/3 of leaf tips are removed. Base of scions are cut to form long, slim wedges. Rootstocks are lopped off close to the terminal where tissue has not become hardened. A longitudinal cut is made in the rootstock deep enough to accommodate the wedge of the scion, and the wounds of stock and scion are bound together with para film or grafting elastics and graft wax. The grafted plant is then placed under intermittent mist to prevent dehydration until the graft union is well healed.
In the case of the mamey, everything is exacting. If leaves of the scion are too old, they will fall off under mist and rotting will be faster than healing. If elastic grafting bands are used, but no wax, the wounded surfaces will buckle out like carrot strips in water and the callous will not grow together. If household rubber bands are used instead of grafting elastics, they slip on the waxed surface and release the graft. Best results to date are 35 out of 37. When tip-grafting mamey under mist, very young plants, two or three weeks old, are best. Tissues are undifferentiated and the cotyledons still provide nourishment. Older plants can be used successfully for rootstocks if the graft is inserted into the cheesy growing tip.
Caimito, black sapote, and jack fruit have growing tips that are much smaller in diameter and are more tedious to handle, however they are not so exacting that everything is right. Also they can be held in place with para film which serves both to hold wounded tissues in contact and to keep water out of the wound.
When making fig cuttings grafts, young succulent, green growth with long internodes serve best. Technique is the same except the rootstocks are mere cuttings which will root while the graft wounds are healing under mist.
DATE: November 1986
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