Tree growth, productivity, and fruit quality of ‘Fuyu’ persimmon trees onto different dwarfing rootstocks

•The candidate dwarfing rootstocks was selected grown in unpruned and nonbearing trees.•Tree canopy volume was more effective than tree height or tree canopy area for evaluating rootstock dwarfing effect.•‘Hourakudai’ had the highest yield efficiency per TCSA and tree canopy volume.•‘Hourakudai’ showed high propagability by softwood cuttings.•‘Hourakudai’ is a practical dwarfing rootstock for persimmon trees. To investigate the dwarfing effect of candidate rootstocks on persimmon (Diospyros kaki Thunb.), we compared the growth of ‘Fuyu’ scions grafted onto ‘Hourakudai’ and S22 clone dwarfing rootstocks with that on a standard D. kaki rootstock, ‘Aogaki’ seedlings, in unpruned and non-bearing trees. In addition, we compared the growth, fruit quality, and yield efficiency of ‘Fuyu’ scions grafted onto three candidate dwarfing rootstocks (‘Hourakudai’, No. 3, and S22 clones) with those of ‘Aogaki’ seedlings grown under conventional cultivation (pruned and fruited). In unpruned and non-bearing trees, grafts on S22 and ‘Hourakudai’ rootstocks reached about 75 % of the height of trees on the standard rootstock. Tree canopy volumes on the S22 and ‘Hourakudai’ rootstocks were about 67 % and 42 %, respectively, of those on the standard rootstock. The high positive correlation between TCSA and tree canopy volume was observed for not only between trees grown under unpruned and non-bearing but also trees grown under pruned and bearing. Tree canopy volume was a better indicator of dwarfing capacity of rootstocks than tree height or tree canopy area. In conventional cultivation, trees grafted on all three candidate dwarfing rootstocks had smaller canopy area and canopy volume than those grafted onto the standard rootstock, from 2 to 11 years after planting. Although differences in tree growth between the three dwarf rootstocks were observed, the differences tended to decrease as tree age advanced. The quality of fruit produced (fruit weight, soluble solids content, and skin color) by trees on dwarf rootstocks did not differ from that produced on standard rootstocks, although annual variations occurred. Trees on S22 rootstock had the lowest yield owing to decreased vigor. Trees on ‘Hourakudai’ rootstock had the highest yield efficiency per trunk cross-sectional area of scions and per tree canopy volume. ‘Hourakudai’ softwood cuttings showed the highest rooting rate (80 %). These results identify ‘Hourakudai’ as a promising new rootstock for growing dwarfed ‘Fuyu’ trees,