Abstract 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, owing to the high yield efficiency without a decrease in fruit quality.

中文翻译：

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'扶余'柿树在不同矮化砧木上的生长、生产力和果实品质

摘要 为了研究候选砧木对柿子 (Diospyros kaki Thunb.) 的矮化效应，我们比较了嫁接在 'Hourakudai' 和 S22 克隆矮化砧木上的 'Fuyu' 接穗与标准 D. kaki 砧木 'Aogaki' 上的生长幼苗，在未修剪和不结实的树上。此外，我们比较了嫁接在三个候选矮化砧木（'Hourakudai'、3 号和 S22 无性系）上的'扶余'接穗的生长、果实质量和产量效率与常规栽培下生长的'Aogaki'幼苗的生长、果实质量和产量效率（修剪和结果）。在未修剪和不结实的树木中，S22 和“Hourakudai”砧木上的嫁接达到了标准砧木上树木高度的 75% 左右。S22 和 'Hourakudai' 砧木的树冠体积分别约为标准砧木的 67% 和 42%。不仅在未修剪和非承载下生长的树木之间，而且在修剪和承载下生长的树木之间观察到 TCSA 与树冠体积之间的高度正相关。与树高或树冠面积相比，树冠体积是砧木矮化能力的更好指标。在传统栽培中，种植后 2 至 11 年，嫁接在所有三种候选矮化砧木上的树木比嫁接在标准砧木上的树木具有更小的冠层面积和冠层体积。尽管观察到三种矮砧木之间树木生长的差异，但随着树龄的增加，差异趋于减小。树木在矮砧木上生产的果实质量（果实重量、可溶性固形物含量和果皮颜色）与在标准砧木上生产的果实质量没有区别，虽然每年都会发生变化。由于活力下降，S22 砧木上的树木产量最低。'Hourakudai' 砧木上的树木在接穗的每个树干横截面积和每个树冠体积上的产量效率最高。'Hourakudai' 软木插条的生根率最高（80%）。这些结果表明，'Hourakudai' 是一种很有前途的新砧木，可用于种植矮化的 '扶余' 树，因为它具有高产量且不会降低果实质量。