by admin | November 27, 2020 11:02 am
Scion: The part of a plant used for grafting upon the rootstock.
Rootstock: The root-bearing plant on which the Scion will be grafted.
Parafilm M: A stretchable, wax like tape. The product has been widely used for routine laboratory work for many years.
Why Graft? • Some varieties of plants do not come true from seeds. • Difficult or impossible to reproduce from cuttings or other propagation techniques. • Using a rootstock better adapted to the prevailing soil and climate than scion produced naturally. • Dwarfing rootstock can be used to greatly reduce the size of the tree. • To increase the supply of new varieties rapidly. • Change a tree from an old to a new variety. • Grafted fruit trees have earlier fruit productions. • Multiple grafts to produce a tree with several varieties or flowering plant with several different colors of flowers
• Rootstock can be selected for characteristics that the scion may not have, such as resistance to root rot or is tolerance to parasitic organisms; such as nematodes, insect larvae or other subterranean pests.
What is Grafting?
Grafting is the process of joining two or more different plants and enabling them to grow as one. The upper part of the graft (the scion) becomes the top of the plant; the lower portion (the rootstock) becomes the root system or part of the trunk. Although grafting usually refers to joining only two plants, it may be a combination of several.
What are the limitations?
Not all plants can be grafted. Plants of the same botanical genus and species can usually be grafted even though they are not the same variety. Plants with the same genus but of a different species may often be grafted.
For the most successful grafting only chose closely related plants to form a compatible union. Generally, this means apple-to-apple, rose-to-rose.
Incompatible grafts may not form a union, or the union may be weak. A poor union results in plants that grow poorly, break off or eventually die. Trial is the only way to determine plants’ compatibility. Some rootstock and scion materials are difficult to get and some plants are not as easily grafted. This can often result in a quite high percentage of loss. This explains why some grafted trees are more expensive.
How to Collect and Store Scions?
Scion wood can collected when available. It should have a diameter of 1/4 to 3/8 inch. Length of scion can be from a few inches to more than 2 feet. Defoliate the scion and wrap the entire scion cuts, buds, and stem in stretched Parafilm M. Wrapping scion with Parafilm M beneficially conserves the internal moisture of the plant tissue. Parafilm M stretches; therefore, a little goes a long way. Cut the Parafilm M into two one inches strips.
If the scion cannot be grafted when obtained, store the scion in a plastic bag in the refrigerator with moist paper towels until performing the graft. If wrapped in Parafilm M the scion can be stored for many weeks. Do not store in a freezer.
When to Graft?
It is best to graft in the spring, from the time the buds of rootstock trees are beginning to open, until blossom time but this should not limit you from grafting at anytime of the year. Graft when scions become available.
What Tools and Materials are Needed? • Knife. A good quality knife, able to hold a sharp edge, is the key to good grafting. Special grafting and budding knives are desirable. Keep material to sharpen the knife handy. • Pruning Shears. • Grafting tape. • Parafilm M. • Fungicide – Spray bottle of Alcohol. Label spray bottle. • Clothes pins.
• Label for identifying the rootstock and scion (Name, variety, and date of the graft).
Grafting Techniques Defoliate the scion and wrap the entire scion cuts, buds, and stem in Parafilm M; (remember to stretch the Parafilm M) the buds will grow through the Parafilm M without damage or restriction. (Note: Parafilm M is heat and photosensitive and decomposes when exposed to direct sunlight for longer than a few minutes.) Store in a cool location.
There are many different types of grafting techniques. The cleft graft is one of the most commonly used and the simplest type of graft to perform.
1. Fungicide tools and hands – spray hands, grafting knife and pruning shears with alcohol. 2. Match the scion and rootstock diameters precisely; this maximizes the chance of matching the cambiums. 3. The defoliated scion from a healthy plant should contain at least one completely dormant node on second-year wood which has had all soft, active growth removed. 4. The stock should be an actively growing seedling (do the grafting during the warmer months – in Florida grafting can be done year round). 5. (See diagram below) Cut the scion (A) and fashion its base into a thin, narrow wedge. A large contact surface area will increase the rate of healing. (Hardness part of a cleft graft) Do not touch the cut surfaces, or allow them to dry out. 6. Cut the rootstock at right angles to the stem in mature wood preferably close to a node. Make (B) a single vertical cut down the middle of the stem. The cut should be the same length as the wedge of the scion. Make sure that all cuts are straight and precise; use a very sharp grafting knife (Rock the knife back and forth – use care not to cut yourself). Do not touch the cut surfaces, or allow them to dry out. 6. Force (C) the wedge into the slit which was made in the rootstock; no gaps should be apparent. Always match the cambium layers on one side during the tying process; don’t worry if both sides are not matching 7. Wrap the graft with stretched Parafilm M. Ensure that all points are covered with Parafilm M. Air and water must be excluded from the graft-point if a successful union is to occur.
8. Wrap the (D) graft firmly with Grafting tape, tying from just below the graft and working up. Care should be taken not to force the scion from the stock when traversing the join. Clothespins can help hold the graft together while wrapping with grafting tape.
9. Label graft with name, variety, rootstock and date of the graft. 10. Place the plant in a stress-free environment such as a shaded (50-90%) area. 11. Examine regularly. The dormant nodes should burst in about 3 to 4 weeks. Remove any buds that develop below the graft point.
12. Remove the grafting tape at a later date.
Some reasons for Graft Failure
• Rootstock and scion were not compatible.
• The cambiums were not meeting properly.
• Scions were upside down (Some plants can be successful grafted upside down). • Grafting was done at the wrong time of the year (Most plants can be grafted year around). • Rootstock or scion were not healthy • Scions were dried out or injured by cold. • The scion was displaced by storm, birds, or other means. • Insects or disease attacked the graft.
• The graft union was girdled because tape was not cut or released in time.
But the main reason for failure is not trying!
Source URL: https://stfc.org.au/articles/grafting-made-easy-2/
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