Rejuvenation

Rejuvenation through top working and recent propagation method adopted for establishment of old orchard

1. Pradeep Kumar Vishwakarma And Jyotika R. Bamaniya Prepared By Rejuvenation through top working and recent propagation method adopted for establishment of old orchard

2. Rejuvenation Rejuvenation means restoring vitality and freshness of plants. It is another name for renewal. Rejuvenation is attempted to make the plant new. In India many existing orchards are not as productive as their potential. Selection of poor planting material, improper plantation and upkeep make orchards uneconomic. These situations necessitate need for rejuvenation. Various factors which make the plant susceptible to rejuvenations are as under:

3. Infestation of orchards Improper planting Planting material Faulty site Adverse weather conditions Attack of pests and pathogen

4. Objectives of Rejuvenation Enhance the productivity of old fruit orchards. Provide quality planting material to farmers at reasonable to increase yield per capital. Make senile orchards productive and juvenile. Enhance the profitability. Conservation of old progeny or species.

5. Top working It is the process of converting an undesirable plant into desirable type. Usually seedling stand of fruit plants are considered suitable for top working. Top-working is generally done on long-lived species, growing in a healthy condition. Short-lived species, diseased trees are not suitable for top-working; in such cases new planting is considered more economical and useful than top-working.

6. To begin with the process, the plants are headed back within 1 meter height from ground level during spring when the plant is in active growth stage. The new shoot appeared in response of heading back are selected and vegetative propagation (budding/grafting) method is resorted during June-July. Any method of grafting (splice, cleft, side or bark) can be-used for top-working. However, cleft is the most popular and commonly used method, especially when thick branches are selected. When younger and thin branches are used, whip and tongue is the best method. Top-working is most successful when relatively young trees are used. The branches to be grafted should be 2.5 to 7.5 or 10.0 cm in thickness.

7. The branches to be top-worked should be cut in such a way that the cut surface is smooth, and is at a point of the branch where there are no knots or smaller branches. Scions for top-working are collected when they are dormant. They should be collected from healthy trees, free from diseases, especially from viruses. Immediately after collection the scions are wrapped with polyethylene film and stored at 0°C. Dormant scions unite with the stock promptly and start growing within a few weeks. During grafting care should be taken to see that the scion is not dried by exposure to the sun. Immediately after each limb is grafted, it should be thoroughly covered with grafting wax, sealing all the exposed cut surfaces.

8. Aftercare of top-worked trees Top-worked trees should be inspected every 3 to 5 days and if the wax covering of the graft joint shown any cracks or holes, a fresh coating of wax should be immediately applied. Sun-burn of the trunk is a serious problem in top-worked trees, especially when grafting is done in late spring and there is no nurse branch. Under such conditions, white-washing the trunk and branches will help in reflecting the radiant energy, and will prevent sun-burn injury by keeping tie bark of the tree quite cool.

9. Usually more than one (2 to 4) scions are grafted to each limb, However, if all the scions unite and grow, there will be excessive crowding of branches. It is better to select the best placed and strongest growing scion for growing permanently and all other weak growing scions should be removed after a few years of observation of their growth habit. The top worked tree should be irrigated periodically and fertilized. Plant protection measures should also be adopted to prevent the rotting of wood and to keep away the bark-eating caterpillars.

10. Techniques of Rejuvenation Pruning Pruning is very powerful technique of rejuvenating the plants. It brings juvenility. While pruning every attempt is made to remove dead, damaged, diseased and interlacerating branches. Generally pruning is resorted at breast height at about 2m height from ground level. Lower the pruning more vigorous is the sprouting. It is the physiological age not chronological age that is most important for juvenility and in turn the ability of the plant to sprout. Further after long bearing age, trees itself enter into senility. Pruning helps in invigorating such trees.

11. Manuring Timely manuring and fertilization is essential for good resume of rejuvenated plants. Manures and fertilizers are applied one month ahead of flowering. On rejuvenated plants upon emergence of new growth micronutrients should be supplied. These nutrients may also be applied repeatedly during new growth stage of plants. However, the requirement of major nutrients especially N, P, K being of higher order, these must be applied through soil application.

12. Thinning of shoots In response to pruning there is emergence of several shoots on the plants, These shoots remain over crowded one over the other. Aeration, penetration of light, space etc among branches are not at all proper. To deal with the situation, only selected number of shoot may be allowed to grow on the plant. While thinning, 4-5 shoots spread all around the plant may be allowed to grow. Rest shoots are removed. Healthy, vigorous, well sprouted and well spaced shoots are retained to constitute framework of rejuvenated plants.

13. Supplemental feeding A damaged plant can be brought back to vigorous stage by arranging for infusion of sap. For this purpose, many seeds are planted near trunk of the plant. They are allowed to grow. When seedlings attain height of about 1metre, they are detopped. Their top portions are incisized in form of wedge. Similar matching cut is given in trunk of plant requiring rejuvenation pruning. After then the seedlings top portions are inserted in bark of damaged plant. After some time union takes place and the seedlings become part of old rejuvenating tree.

14. Control of devitalizing agents Pests and diseases act as major devitalizing agent of plants. In woody perennial plants there is heavy incidence of bark eating caterpillar, trunk borer, leaf eating caterpillar pests, etc. In long run these pests devitalize the plants. With trunk borer, the plants xylem tissues are damaged, the flow of cell sap is hampered and the plants enter the stage of decadence. Diseases also ruin the health of plants. Leaf spot disease, pink diseases, stem rot, root rot, etc. take a heavy toll on survival of plants. These causative diseases need timely control.

15. Cleft grafting It is one of the oldest techniques of top working trees. It is also useful for propagating small trees. In case of top working tree, the use of this technique should be limited to branches of about 2.5 to10 cm diameter. The plant species which has straight grained wood and splits evenly, are considered ideal for cleft grafting. On the stub to be grafted, a downward vertical split of 5 to 8 cm length is prepared. The vertical incision is made on two sides of stock. The scion shoot of 8 to 10 cm length and pencil thickness is used. Matching incision is prepared on lower portion of scion. The scion is inserted in vertical slits of rootstock.

16. Wedge grafting Old trees can be rejuvenated through wedge grafting. The plant is cut in form of stub at about 1 m height from ground. V-wedge about 5 cm deep is prepared in the side of stub. Similar matching V shape cut is prepared at the bottom of scion. The scion is tapped downward firmly into place. It is kept outward slightly at the top to have a best match of cambium layer. Every attempt is made that scion should be held tightly in place to prevent its dislodging.

17. Bridge grafting It is used to repair the plants. Quiet often plants receive injury due to cultivation equipments, winter injury, diseases, pests, rodents, etc. The damage is excessive, the tree is very sure to die. Actually the damage causes hindrances in translocation of nutrients from top to roots. Bridge grafting takes care of it. It is best performed during early spring when the plant is actively growing and there is slipping of bark easily. The scion should be obtained from 1 year old growth. Dormant scion of 6-13 mm diameter is used for grafting. Before attempting bridge grafting wounded area is trimmed back to healthy, undamaged tissue by removing dead or damaged part. V-shape incision is made at the tip and also the bottom of rootstock to insert scion. The scion is inserted every 5-7 around the injured section of the plant. After insertion of all scions, the cut surface must be covered by graft wax.

18. Frame working Grafting many small secondary scaffold branches high on the tree constitutes frame working. It requires insertion of grafts throughout the main frame of the tree. A large number of scions is required to replace the small laterals and scaffold branches. Growth coming out of the previous frame of the tree is removed time to time to favour establishment of the scions. Frame working is resorted using budding/grafting technique. The frame worked plants reward good fruiting. But, the technique being cumbersome and expensive, it is not practiced commercially in the orchard.

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