Effects of the characteristic annual ring structure in snow resistant Japanese cedar on basal bending

2019 Fiscal Year Final Research Report

• Project/Area Number: 17K07850
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Research Field: Forest science
• Research Institution: Yamagata Prefectural Forest Research & Instruction Center
• Principal Investigator: Miyashita Tomohiro 山形県森林研究研修センター, 森林資源利用部, 研究員 (80370849)
• Co-Investigator(Kenkyū-buntansha): 高田 克彦 秋田県立大学, 木材高度加工研究所, 教授 (50264099)
• Project Period (FY): 2017-04-01 – 2020-03-31
• Keywords: 根元曲がり / 木材強度 / 抵抗性育種 / 雪害

Outline of Final Research Achievements

Some cultivars are resistant to basal bending that occurs on Japanese cedar planted in regions with heavy snowfall. The mechanism of resistance is not fully clarified. However, it has been pointed out that wood strength traits may contribute to the resistance. Therefore, in this study, we investigated the relationship between various wood traits and resistance in snow resistant cultivars.
Tracheid length, microfibril angle (MFA), basic density, and stress-wave velocity were measured. The traits that were significantly different between resistant cultivars and controls were MFA and stress-wave velocity. Both traits are related to modulus of elasticity. In particular, MFA formed in juvenile age were strongly associated with resistance. This suggests that cultivars with a high modulus of elasticity in juvenile age should be more resistant to basal bending.

Free Research Field

林木育種学

Academic Significance and Societal Importance of the Research Achievements

耐雪性スギの従来の選抜方法は根元曲がりの大きさに注目して行われている。しかし、根元曲がりは環境の影響を受けやすい形質であるため、遺伝的に抵抗性が低いにも関わらず根元曲がりが小さな個体を誤まって選抜することがあった。
一方、木材強度は環境の影響を受けにくい形質である。このため、根元曲がりの大きさに加えて、応力波伝播速度や幼齢期のＭＦＡを調べることにより、抵抗性が低いにも関わらずたまたま通直であった個体を誤選抜するリスクの軽減が期待できる。すなわち、抵抗性に対する優良系統の選抜において、根元曲がりの大きさと木材強度の２形質を採用することにより、選抜精度を向上できると考えられる。