GROWTH PERFORMANCE OF JAPANESE PERSIMMON 'FUYU' GRAFTED ON DIFFERENT DWARFING ROOTSTOCKS AND RELATIONSHIP BETWEEN CANOPY VOLUME AND SHOOT LENGTH

We compared the genuine growth performance of Japanese persimmon (Diospyros kaki Thunb. ‘Fuyu’) grafted on three dwarfing rootstocks (No. 3, S22, and D. rhombifolia) with that of ‘Fuyu’ on conventional seedling rootstock (D. kaki ‘Ao-gaki’) as a control. To eliminate the influence of pruning and fruit bearing on vegetative growth of the trees, we left all trees unpruned, and thinned all flower buds by hand each year. After 6 years’ growth, tree height, canopy volume, and total shoot length were largest in the control trees. Trees grafted on D. rhombifolia rootstock were the most dwarfed, but their total shoot length and number of shoots were very low. The tree height and canopy volume of trees on No. 3 were 78% and 50%, respectively, of the control. Trees on S22 showed similar semi-dwarfing effects. The canopy volumes of all trees were positively and linearly related to the total shoot length, number of shoots, and trunk cross-sectional area of the scion.