Dwarf apple trees generally are produced by propagating the desired cultivar on dwarfing rootstocks. The technique of greenwood grafting is most often used in the production of dwarf apple trees. This paper describes an investigation into the effects of the planting methods and grafting methods on the growth of 7-year-old dwarf apple tree. The effects upon the quality of different methods of grafting was also investigated. Trees were planted April 1, 1974. Tree height, spread, trunk circumference, number of flower bud and root distribution (depth and width) were investigated on April 3, 1977 and March 15, 1980.
Spur EarliBlaze on M7 raised by conventional grafting method showed earlier fruting than those on M7/seedling raised by softwood grafting. After 7 years, however, there was no significant differences in growth, root distribution and dwarfing between conventional grafting and softwood grafting. Trees of EarliBlaze and Starkrimson on dwarfing rootstocks/seedling raised by softwood grafting were planted deeper than normal and then, after 7 years, seedlings were naturally deteriorated.
In softwood grafting method, trees which planted after taping polyethlene film at the union of seedling produced a great amount of shoot and root growth and flower buds. After 7 years, however, there was no significant differences.
Dwarfing charateristics of size-control rootstocks were not influenced by the softwood grafting method, itself.
As for the horizontal and vertical root distribution, 7-year-old Spur EarliBlaze on M7 showed 300㎝ spread and reached 110㎝ deep. As for the root distribution, Spur EarliBlaze on M7/seedling raised by softwood grafting showed 377㎝ spread and 120㎝ deep and those by removal seedling at the time of planting showed 370㎝ spread and reached 110㎝ deep. As for the horizontal and vertical root distribution. EarliBlaze on M26/seedling by softwood grafting showed 220㎝ spread and reached 80㎝ deep and 106/seedling by softwood grafting showed 480㎝ spread and reached 140㎝ deep. Root system of Starkrimson/seedling by softwood grafting penetrated 130㎝ deep and showed 335㎝ spread.
Holes for planting of dwarfing apple trees in Korea should be wide enough and deep enough to accommodate the roots in their natural position.
|