The local mango is used for rootstock because
- It is tolerant to soil borne diseases
- It is compatible with many improved varieties
- Seed is readily available and cheap
- It has got a good root system with a long tap root
- In addition to the above, a good rootstock must be vigorous in growth, uniform and able to induce regular bearing
- Mango seeds are considered non dormant i.e. at the time of harvest they are physiologically and morphologically mature.
- Their moisture content is high and thus cannot withstand sever desiccation.
- As a result, preserving them is difficult.
- Seeds of mango have irregular germination, they cannot be at the same stage of development at any given time indicating a variation in the vigor of individual seeds.
- It is recommended that seed to be used as rootstock be collected from current season’s harvests.
- Mango seed, if not properly stored, will remain viable for 1 to 2 months.
- If stored in moist charcoal, mango seed can remain viable for at most 3 months.
- During seed selection remove rotten, damaged and very small seed.
Processing seed for planting
- Remove the stone before planting;
- To quicken germination. Seed without stone (cover) germinates in 10 to 18 days while that with stone germinates in one month.
- To reduce re-infection of seed
- To expose seed for better selection. Only healthy seed should be selected for planting. All weevil-damaged seed should be discarded.
Before planting, dip seed in solution of insecticide plus fungicide to kill the weevils, their eggs, grubs and any other seed-borne diseases e.g. anthracnose
Substrate for use in the nursery
Characteristics of a god substrate
- Light in weight and easy to transport but heavy enough to hold cuttings and seedlings firmly in place and doesn’t swell or shrink in a way that may damage the plant.
- Good water holding capacity, aeration and drainage
- Free from weed seeds, nematodes and pathogenic organisms
- Can be sterilized without changing the characteristics
- Adequate fertility (contains all necessary nutrients for plant growth and development)
- Readily available
- Relatively inexpensive
Such a substrate is usually a mixture of forest soil, well-decomposed organic matter and some inert material that will enhance its physical characteristics.
Grafting of Mangoes
Mango rootstocks are ready for grafting when 5 to 6 months old. Cleft or wedge grafting can be used.
- Grafting: the technique of connecting two pieces of living plant tissue together so that they unite and form a functional plant.
- Scion: the aerial part of a tree that will form the crown of the new plant. This part contains the dormant buds of the tree whose desired characteristics need to be multiplied.
- Rootstock: the belowground or lower part of a tree, sometimes including part of the stem and some branches that will form the root system of the new plant. This part may also contain dormant buds, which should not be allowed to develop on the new plant since they do not have the desired characteristics that need to be multiplied.
- Vascular cambium: a thin layer of meristematic cells between a tree’s bark and wood. Meristematic cells are capable of dividing into new cells that may differentiate into new tissues and organs.
Reasons for Grafting
- To obtain a tree which combines both the good characteristics of one tree and the rootstocks of another.
- To shorten maturity period of the trees.
- To perpetuate clones that cannot be readily maintained by cuttings, layers, division or other asexual methods.
- To maintain characters of plants unlike the case is with sexual reproduction.
- To change cultivars of established plants.
- To detect viral diseases.