Epicotyl Grafting: A useful techniques of Mango Propagation
Authors:Dr Jai Prakash and Kanhaiya Singh
Division of Fruits and Horticultural Technology
ICAR-Indian Agricultural Research Institute, New Delhi-12
* Correponding author email: singhjai2001@rediffmail.com


Introduction

Mango (Mangifera indica L.) is known as "King of Indian Fruits" and is grown commercially in tropical and subtropical climatic region of India. Healthy and good quality plant materials are the foundation of successful fruit production. The targets of the enhancing Mango production in the coming years will be achieved only through production and distribution of healthy, genuine and quality planting material of commercial/improved varieties of Mango in sufficient quantities. The maintenance of the rootstocks about one years to perform the veneer/soft wood grafting is labour intensive and cumbersome process and ultimately long time and resources are required for the preparation of the grafted plants. With the advent of the epicotyl or stone grafting, it is possible to develop the grafted plants for the sale and plating within one year with less investment particularly in humid tropical areas of the India. This article is an effort to highlight epicotyl grafting for commercial propagation of mango cultivars.

Protocols for epicotyl grafting of mango:

Mother Plants:

The bud sticks/graft wood should always be taken from healthy and true to type progeny trees of commercial/new varieties, which are free from viruses, disease and pest occurrence. A nurseryman should have progeny trees of all the promising cultivars of fruits that can be grown in that particular area with special care management.

Selection of mother plants:

• Mother plants of the variety should be genetically true to type.
• The plants should be healthy and free from any diseases, pest infestations.
• The plants should have known pedigree records regarding bearing potential, fruit quality and problems.
• The plants should be precocious and prolific bearer.
• Commercial fruiting should be avoided in mother plants to ensure supply of scions.

Selection of rootstocks:

• Dwarfing /semi-dwarfing should be preferred that vigorous.
• Compatibility with the known commercial variety.
• Resistance/tolerance to biotic (diseases and pests) and a biotic stresses.
• Rootstock should have well developed root system.

Improved cultivars/hybrids: Amrapali, Mallika, Ratna Pusa Arunima, Pusa, Peetamber, Pusa Pratibha, Pusa Surya and Ambika.

Raising of rootstocks:

Mango seedlings grown from stones of seedling trees are used as rootstocks. Stones should be collected from local varieties of dwarf, disease free and high yielding trees of seedling mangoes during July-August. Mango seeds are recalcitrant and lose viability very soon on desiccation. Before sowing stones should be immersed in water and floating stones should be discarded, as they are not considered viable Stones are sown during in May to August, depending upon the ripening season of the mango, in beds mixed with well-decomposed farmyard manure. When the seedlings will attain the age of 10-15 days, they are fit for the grafting operation. If, grafting will not be successful then it is desirable to allow the one sprout to develop as rootstock for the softwood/veneer grafting after 8-10month.

Collection of Scions:

Proper selection and preparation of scion are of utmost importance in various types of grafting. The scion preferably a terminal non-flowered shoot of 3 to 4 months maturity. Selected scions should be defoliated on the mother plant about 7 to 10 days prior to detachment. It is desirable to keep a part of the petiole intact on the selected terminal shoot, matching with the thickness of the rootstock. Matching of scion thickness is most important for the success of stone grafting.

Stone or epicotyl grafting

Epicotyl grafting is a technique of faster multiplication of mango. Fresh mango stones are collected and sown in the nursery beds. After germination, 10-15 day old seedlings with tender stems and coppery leaves are lifted with along with stones. The roots and stones are dipped into 0.1 per cent Carbendazim solution for 5 minutes after washing the soil. The seedling stems are headed back leaving 6-8 cm long stem. A 3-4.5 cm longitudinal cut is made into the middle portion of the cut stem. A wedge shaped cut starting on both sides is made on the lower part of scion stick. The scion stick should be 4-5 months old and 10-15 cm long containing plumpy terminal buds. The scion stick is then inserted in the cleft of the seedlings and tied with polythene strip. The grafts are then planted in polyethylene bags containing potting mixture (1:1). The bags are then kept in the shade protecting from heavy rain and sunlight. When the scion sprouts and the leaves become green and the graft union healed up after 45 to 50 days then the polythene strip should be removed and all the unwanted sprouting coming below the union also discarded. This technique is done in the month of June and can also be performed up to first week of August or subject to availability of the seed/stones. The day's wise schedule of the epicotyl grafting is presented in Table 1.

Merits:

1. It is an economical technique by minimizes the expose towards the cost management of rootstock up to one year. .
2. It is less time consuming as the rootstock is used in the early stage.
3. Early supply of grafted plant can be done.

Demerits:
1. Required skillful personal.
2. To get large quantity of grafting is quite difficult due to compulsion two weeks old rootstock. Beyond this period the success rate of propagation reduce drastically with increase in the age of rootstock.

Table 1. Standard criteria for Stone or epicotyl grafting in mango
Sl. No Characters Standards
1. Type of root stock Straight & Vigorous growth
2. Raising of root stock Polyethylene bag
3. Age of root stock 10 to15 days
4. Diameter of root stock 0.2-0.3cm
5. Age of scion shoots 3-4 months old
6. Diameter of scion 0.3-0.4 cm
7. Length of Scion stick 10-15 cm
8. Plant Height 20 cm
9. Stem girth 1.5-2 cm
10. Union Height 5-7 cm
11. Time of grafting June-August (vary with the availability of fresh seed)
12. Union maturity for strip removal 40-45 days


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About Author / Additional Info:
I am working as a senior scientist at IARI New Delhi.