形質ベースの枠組みにより軽量木材樹種の育種を加速(Trait-Based Framework Accelerates Breeding of Light Wood Trees)

2026-08-28 中国科学院(CAS)

バルサ材は世界最速級の成長速度を持つ一方、組織培養や挿し木による増殖が難しく、品種改良には交雑育種が重要となる。中国科学院西双版納熱帯植物園(XTBG)の研究者らは、エクアドル、インドネシア、スマトラ由来の親木から作出した9品種のバルサ雑種を対象に、2年間の共通圃場試験を実施し、光合成、葉・茎構造、力学、水理特性など22の機能形質と成長速度を比較した。その結果、成長の速い品種は光合成速度や葉窒素濃度などが高い「獲得型」、遅い品種は葉の厚さや葉面積当たり重量、機械的強度などへの投資が大きい「保守型」の戦略を示した。特に葉の形質が成長予測に有効で、光合成能力、リン利用効率、葉窒素、葉厚、葉面積当たり重量、葉の強度、ヘミセルロース濃度、保水性の8形質が有力な選抜指標となった。これにより、優良バルサ品種の早期選抜と育種サイクルの短縮が期待される。

形質ベースの枠組みにより軽量木材樹種の育種を加速(Trait-Based Framework Accelerates Breeding of Light Wood Trees)
Balsa tree (Image by XTBG)

<関連情報>

9つのバルサ( Ochroma lagopus)品種における生育性能の特性に基づく評価と予測 Trait-based assessment and prediction of growth performance across nine balsa (Ochroma lagopus) cultivars

Mingyi Li, Gaojuan Zhao, Huipeng Xi, Zhiming Zhang, Jianping Wu, Yike Zou, Yanru Hou, Qianzhang Yang, Changchao Fu, Han Liang, Jingchao Li, Phisamai Manpuen, Yang Wei, Amy Ny Aina Aritsara, Zhubiao Duan, Shubin Zhang, Yajun Chen
Industrial Crops and Products  Available online: 21 August 2026
DOI:https://doi.org/10.1016/j.indcrop.2026.124064

Highlights

  • 22 key functional traits were evaluated across nine hybrid balsa cultivars in this study.
  • Faster-growing balsa cultivars exhibited more acquisitive functional traits and leaf water-retention capacity.
  • Slower-growing balsa cultivars displayed more conservative and higher-safety strategies.
  • Functional traits provide valuable guidance for targeted balsa breeding practice and cultivation management.

Abstract

Balsa (Ochroma lagopus Swartz) is a fast-growing tropical timber species of high economic value, yet different balsa cultivars often exhibit considerable variation in growth performance. Hybridization using elite parental cultivars, combined with trait‑based screening, provides a promising route for accelerating breeding; however, the predictive power of functional traits in timber species such as balsa has rarely been tested. In this study, we quantified 22 leaf and stem functional traits that related to photosynthesis, structure, biomechanics, and hydraulics across nine balsa cultivars derived from hybrid parents of different origins, and monitored growth performance over two years. The results revealed significant inter-cultivar variation in both growth rates and functional traits. Overall, structural traits exhibited trade-offs with traits enhancing photosynthetic capacity, while hydraulic efficiency was negatively related to structural investment, mechanic resistance, and drought tolerance. Variations in growth performance among cultivars were well explained by coordinated trait syndromes, with explanatory power ranging from 53% to 86%. Specifically, faster-growing cultivars exhibited an “acquisitive” strategy, characterized by higher photosynthetic rate (Am), photosynthetic phosphorus-use efficiency (PPUE), and leaf N concentration. In contrast, slower-growing cultivars displayed a “conservative” strategy with greater structural investment (leaf mass per unit area, LMA; leaf thickness, LT), higher leaf water-retention capacity (T70), and stronger leaf (Fp) and stem mechanic strength (MOE). Our findings establish a robust trait-based framework for early screening and provide practical guidance for targeted hybridization, thereby facilitating more efficient balsa breeding practice.

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