Effect of cutting size on rooting ability and first year growth of Pinus thunbergii in nursery containers

ABSTRACT

To improve the productivity of rooted cuttings in pine wilt disease-resistant Pinus thunbergii, the effect of cutting size on rooting ability and first year growth was studied. Sprouts collected as cuttings from four genetically different clones were assigned to various size combinations (five or six classes by diameter and four by length). One year after insertion, rooting percentages and height of rooted cuttings were measured and GLMM and LMM analyses applied to assess the effect of cutting size. Small diameter cuttings showed high rooting ability and lesser height, whereas large diameter cuttings showed low rooting ability and greater height. Therefore, results suggest there is an optimum intermediate diameter to maximise the productivity of rooted cuttings. Longer cuttings showed greater height but cutting length did not affect rooting ability. Rooting ability and first year growth differed among clones, suggesting that the optimum diameter for high productivity differs among clones, and highlighting the importance of selecting suitable clones to improve productivity.

KEYWORDS:

• Cutting diameter
• cutting length
• Japanese black pine
• clonal variation
• rooting percentage

Acknowledgments

We thank Dr. Kurita for reviewing the draft. We are appreciative technical staffs of KRBO for their continuous support of our research.

Disclosure statement

No potential conflict of interest was reported by the authors.

Supplementary material

Supplemental data for this article can be accessed here.