Fruit Nursery Establishment And Grafting Techniques
The success of failure of an orchard is largely dependent on how well the propagating and growing of fruit trees has been done in the early stage, therefore proper nursery care is crucial.
An individual grower in most of the cases does not produce his own plants, although if nursery plants are not available, it will be forced by the circumstances to do so.
The nursery should be located in an area which is climatically suitable for the species being grown.
Nursery requires deep, well drained soil for growing seedlings in suitable conditions, preferably in polyethylene bags.
A reliable water source that guarantee water all year round is necessary.
After the site has been selected, propagation structure should be erected.
After the layout is complete, areas to be used for propagation beds and filed areas for the production of filed stock (plants grown in the ground as opposed to those grown in plastic plant bags or other containers) should be tested for nematodes and, if necessary, fumigated with methyl bromide, EDB (ethylene dibromide), or some other fumigant. Even if nematodes are not a problem, the fumigation of nursery beds is desirable as a control for soil-borne disease and insects.
A simple shade structure can be constructed by using poles to support a roof of wire mesh upon which a thin layer of thatching grass or a black shade net is tied to give filtered sunlight beneath. This type of structure (especially if also provided with grass walls) can be used to propagate many species of fruit crops and can also be used for growing newly transplanted stock. Poles should be treated with a wood preservative to prevent rotting and termite damage. Creosote may be used below ground level but should not be used above ground as it gives off fumes which are toxic to plants. Copper-containing preservatives such as copper naphthenate are ideal if they are available. If these materials are not obtainable, soak the bottom of the poles in paraffin (kerosene) so that the poles are protected to 15cm above the soil level.
Good quality potting soil mixes for containers is a must to growth successfully a seedling.
The first prerequisite is to guarantee a media free from nematode, insects and pathogens.
To do so, it is always recommended to kill the pathogen using fumigation (chemicals) or high temperatures (heat) through “solarisation” (put 20cm layer of soil mix under a plastic thin foil and under the sun), or heating a drum full of soil with firewood.
The soil mix should therefore ideally be taken from virgin land (forest) it should be rich in organic matter and should also have a good percentage of sand which can improve drainage and aeration.
However, the best soils for a potting mix are sandy loams taken from the top 15cm below a grass cover.
To obtain good quality mango and avocado trees, seedlings are generally grafted in their early stage, using cleft technique;
But what is grafting, and why it is useful. Grafting is a form of propagation, which involves the union of two separate woody pieces.
The upper part is the “scion”, which combines with the “stock” (lower part). The stock and the scion must belong to the same species or to the same family, to guarantee success in the “union”. Grafting is executed to combine the quality of two plants. It could be done to ameliorate the quality of a plant and strengthen the plants against diseases.
If propagation is carried out by seeds there is no guarantee that the desired character will appear in the offspring. When grafting is successful, the quality of the plants from which the scion is taken are enhanced by the vigour of the plant which serves as the rootstock.
Hereunder listed are the main common grafting techniques for mango and avocado propagation:
Cleft grafting. The steps in cleft grafting are as follows:
Wipe any soil or debris adhering to the stem of the stock.
- Cut back the stock to the point where there is active growth or where the bark easily separates from the wood. Leave 2 or more leaves intact below the cut.
Cut the stock down the centre deep enough to hold the wedge.
- Choose a scion with a diameter as big as the stock.
- Cut the scion to a length of 10-15 cm.
- Shape its base into a short wedge (about 2-3 cm).
- Insert the scion to the stock with care to line up the junction between bark and wood of the two.
- Tie the graft with , grafting tape
- Cover the union with grafting wax or waterproof material