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

(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 -