Seed Health Management for Better Productivity - Govind Ballabh ...

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(Seed Health Management for Better Productivity)growth or from adventitious buds formed after roots are taken out. The length of root sections mayvary from 5 cm to 30 cm and diameter from 0.5 cm to 2 cm. Root sections are cut during dormantseason of plant growth. These are called “thongs” and put in the soil horizontally. Tree species likeBombax ceiba, Artocarpus indica, Ailanthus excelsa, Robinia pseudacacia, Cinnamomumcamphora, Ougenia oojeinsis, Capparis aphylla, etc. can be raised by this method.iv) Root and shoot or stump cuttingsFor the species such as Tectona grandis, Bombax ceiba, Gmelina arborea or Dalbergiasissoo, stumps are prepared from nearly one year old seedlings raised in the nursery beds. Theplants are taken out or uprooted with naked roots. The main axis of plant is cut to include a portionof stem and taproot having nearly 30 cm length. The cut is given just 2 or 3 cm above the collarwith a sharp knife, axe or pruning scissor. The length of a normal stump for teak is nearly 8 to 10inches. The taproot is cut at 15-25 cm from collar. The thickness may vary from 1 to 2 cm. ForDalbergia sissoo the normal stump size can be about 6 inches. Planting by this method isconvenient and economical. In dry areas longer root-shoots are required. Undersized stumps canbe planted in polythene bags for beating up of causalities.LayeringLayering is a common practice to form roots on branches when they are attached to thetree. After rooting, stem is detached and planted. Layering can be of two types : Air layering Soil layeringAir LayeringThe air layering is employed for plants that do not graft or do not root from cuttings. Airlayered branch is a part of parent tree even after layering and have in general better balanced rootsystem than cuttings. In this method a strip of bark or cambium is removed around the branchbefore or during the summer and then this wound is covered with moss or other moisture holdingmaterial and tightly fastened around with polythene piece so that moisture is retained. Rootinducing harmones can also be applied. It takes nearly 3 to 4 months in rooting. After rootingbranch is severed and can be used for planting in pot or whereas desired. Dalbergia sissoo, Morusalba, and Ficus carica can be propagated by air layering.Soil LayeringOne end of the branch or shoot is bent and buried flat into the soil. When adventitious rootsare developed at the base these are severed or removed to form new plants. For some species aring of bark 1 cm wide is removed at a place where rooting is desired. Morus alba and Ficus canbe propagated by method.GraftingGrafting is the joining together of plant parts by means of tissue regeneration. The part thatprovides the root is called the stock and the added piece is called the scion. The scion is detachedfrom the parent plant and the shoot of the other plant is severed to get a new plant. The success of- 146 -
(Seed Health Management for Better Productivity)the graft depends on the matching of the cambia of scion and stock. The scion and stock can beunited in many ways and this decides the type of grafting. When the scion consists of a single budthe process is called budding. In grafting the stock and scion is placed in intimate association sothat the resulting callus tissue forms a living continuous connection. Tape, rubber, etc. can beused to achieve close contact. The grafting is successful when the stock and scion are of thesame species. Grafting is impossible or very hard to promote rooting in different species. Normallydormant scion and actively growing stock are collected. The best period of grafting begins whenthe buds of the stock plants start to swell and continues throughout late-spring. Soft-wood graftingis done from late spring to early summer. Grafting in winter is not done as low temperature will notallow the survival of grafts. If the scions are to be transported to long distance the cut ends aredipped in melted wax to check drying. The various type of grafting are : cleft grafting, veneergrafting, side grafting, whip and tongue grafting, splice grafting, bark grafting, etc. In cleft graftingthe shoot tip of stock plant is removed and a vertical cut is made through the centre of pith. Thescions 30 to 45 cm long are prepared by making tapering cuts in the form of wedge-shapedsegment. Now the scion is inserted into the split and the union is fastened by rubber or tape. Thestock is selected from 2 to 3 year old nursery plants having girth of 1 to 2 cm at 20 to 25 cm heightfrom the ground. April and May are the best period for cleft grafting. In veneer grafting the base ofthe scion is cut diagonally and a wedge shaped patch of bark of almost same size is removed fromthe side of stock. Now the scion and stock after matching are tied together. After the graft whenunion gets healed the upper portion of the under stock is removed.BuddingIn budding, a bud with some portion of the bark of a genetically superior plant is grafted onan inferior plant to produce shoot when the old shoot of the stock is cut off. The bud is grafted inthe form of a patch after removing the bark of the stock or by making a T-shaped incision in thestock. The scion is tied on the stock but the uncovered. April and may are the best period for thebudding. The budding has been demonstrated for raising teak seed orchards. The teak seedorchards raised through bud grafting can be used for getting quality seeds of teak.Vegetative Propagating StructuresThe various types of propagating structures are :1. Shed-roof2. Shade house3. Propagating frames or misting units4. Green house5. Mist chamber6. Growth area chamber or hardening chamberAll these structures aim to optimize following five environmental factors that are necessaryfor growth and development of plants : (i) light (ii) water (iii) temperature (iv) gases and (v) mineralnutrients.- 147 -
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potential. An improvement in qualit
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9. Session Arrangement CommitteeDr.
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9. Dr. Pradip Kumar BorahSr. Scient
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TRAININGONANNEXURE-IIISEED HEALTH M
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ANNEXURE-IVCENTRE OF ADVANCED STUDI
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SundayApril 6MondayApril 7TuesdayAp
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TuesdayApril 15WednesdayApril 16Thu
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