Authors: Jai Prakash and K. Singh
Division of Fruits and Horticultural Technology
IARI, New Delhi
Singhjai2001@rediffmail.com
Introduction
Mango (Mangifera indica L.) is known as "King of Indian Fruits" and is grown in almost all parts of India; because of its great utility and taste. Healthy and good quality plant material is the foundation of successful fruit industry in any state. Now a days, farmers are in search of new alternative, especially when the Government provides several incentives through Horticulture Mission, National Horticulture Mission, National Horticulture Board, NABARD, Land Use Board, RKVY, MNREGA and other schemes of Ministry of Agriculture, Environment and Rural Development. 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 purity is easy in vegetatively propagated fruit crops as compared to seed propagated ones. Still it requires a close monitoring at different stages in the nursery to avoid mixing with other varieties. This article is an effort to popularize the commercial method of mango propagation of mango cultivars.
Protocols for propagation 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.
Criteria for selection of mother plants:
i. Mother plants of the variety should be genetically true to type.
ii. The plants should be healthy and free from any diseases, pest infestations.
iii. The plants should have known pedigree records regarding bearing potential, fruit
quality and problems.
iv. The plants should be precocious and prolific bearer.
v. Commercial fruiting should be avoided in mother plants to ensure supply of scions.
Criteria for selection of rootstocks:
i) Dwarfing /semi-dwarfing should be preferred that vigorous.
ii) Compatibility with the known commercial variety.
iii) Resistance/tolerance to biotic (diseases and pests) and a biotic stresses.
iv) Rootstock should have well developed root system.
v) It should be easy to propagate by vegetative means.
Commercial cultivars:
Established cultivars: Langra, Banganpalli, Dushahri, Alphanso, Malda, Fazli, Himsagar, Kishenbhog and Gulabkhas.
Improved cultivars/hybrids: Pusa Arunima, Pusa, Peetamber, Pusa Pratibha, Pusa Surya, Ambika, Amrapali, Mallika and Ratna.
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. If the mango stones are not sown within a few days of their removal from the fruit, they can be stored under moist condition in shade, covering with moist soil, sand or sawdust, etc. 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 attain the age of 2 months (except stone grafting where only two week old rootstock are acceptable) they should be transplanted into polybags. After transplanting, proper care should be exercised in irrigating the young transplanted seedlings. Infestation of shoot borer is common during early growth season; it cut the young copper leaf as well as young green leaf cause great effect in the seedlings growth. Care should be taken well in advance for their control before damage. Plant is allowed to grow as a single stem for six to eight months is mostly preferable. When the plant attains pencil thickness or a little more, it is ready for grafting.
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 are defoliated on the mother plant about 7 to 10 days prior to detaching. Keeping a part of the petiole intact on the selected terminal shoot also matching with thickness with the stock.
Methods of propagation:
Method of propagation of mango in the earliest time was commenced by seed means, by the days of advance, as seed does not produce true to type propagation technique has been shifted on vegetative propagation as it usually provide true to type seedling. In mango another phenomena viz. polyembryony seed also produce true to type bur very rarely it is being utilized in propagation of mango. Nurserymen in many of the mango growing areas still use inarching, traditional method of propagation. During past few decades, experimental results have shown that veneer-grafting technique can be used with high success rate in North and Central India. Stone (epicotyl) grafting is suitable for Coastal regions as well as mostly confined in high humid and moderate temperature prevailing areas i.e. Eastern India. Now-a-days softwood grafting is being used commercially for mango propagation in several parts of south India as well as in north India. Soft wood grafting and veneer grafting techniques can be used for large-scale multiplication of mango in north India. With the use of polyhouse and net house structures, period of propagation can be extended easily in various mango growing regions of India.
According to the growth stage and time of propagation maximum utilization of the root stock can be done by following different propagation as given below: one after another.
Softwood grafting
The technique of Softwood grafting is becoming commercial technique in most of the mango producing states of the country. The grafting operation is performed on 6 month to 10 month-old rootstocks. The scion shoots of the thickness equal to that of rootstocks are defoliated 7-10 days prior to grafting about 10-15 cm long. 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 graft should be secured firmly using 1.5 cm wide, 200-gauge polyethylene strip. After 45-50 days the unions become complete and scion sprouts, then the polythene strip used to remove. Combination of high humidity and moderate temperature for longer period (May-September) congenial for higher success of soft wood grafting.
Merits
1. Easy to perform and higher success.
2. Higher number of grafting can be done in short periods.
3. It is an economical method.
Demerits
1. Required skill person to perform.
2. Some varieties (Himsagar) show less response to this technique.
Care of nursery plants and grafted plants:
Preferably the young seedlings of mango are transplanted on polybag (6’x5’size) should be free from pest, disease and weed. Under tropical climatic region high intensity of light may become deleterious for young nursery plant. High light intensity during March end to April cause serious damaged to the young plant. For this the nursery plant should be covered with shade, made of thatches, polythene and shade net. The February onwards up to onset of monsoon irrigation should be given at 4-6 days intervals wherever soil is porous in nature.
Grafted plant should be kept in clean place, with regular inspection over the new bud initiation and shoot emergence. After graft union the polythene strip should be removed for proper growth and development of the grafted plant. The leaf or bud emergence below the graft union should be removed which help to grow the desired plant.
Plant Protection Measures:
Insect pests:
Leaf cutting weevil (Deporaus marginatus): This is the major pests attacking mango nursery. It cut the newly emerged leaves at the base of the lamina in the form of a clear and sharp cut of root stock and freshly prepared grafts. The freshly emerged leaves could be protected effectively by spraying 0.05% endosulfan or 0.04% monocrotophos, 0.05 dimethoate 2-3 times at 10 days interval at emergence of new leaves.
Shoot Borer (Chlumetia transversa): The damage is caused by caterpillars which enter the young shoots from terminal end and bore to a depth of 8 - 10 cm. The affected shoots wilt and dry up. Removal of shoot borer affected grafts/seedlings followed by spraying either 0.04% monocrotophos, 0.05 dimethoate or 0.01% carbaryl 50 WP is recommended for the effective control of shoot borer.
Diseases:
Root rot and Damping off (Rhizoctonia solani): Circular to irregular water-soaked patches girdles the entire base of the seedling. Diseased tissues become soft, dark brown or black and seedling collapses and dies. Rotting spreads both above and below the stem down up to roots, disintegrating it, and plant dies. Spraing of copper oxy chloride (0.3%) or ridomil 2gm /liter of water 2-3 times on plant and soil at 10days interval.
Anthracnose (Colletotrichum gleosporides): The leaves and shoots are affected by it in young growth stage of seedling/grafts. The characteristics symptom is the appearance of black necrotic areas on the affected parts. Application of Copper oxy chloride (0.4%) 2-3 as soon as symptoms will observe on plants/plant parts and it is most effective to mange the anthracnose.
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