Balsa wood, the lightest commercial timber globally, is a crucial material for producing lightweight composites—particularly in wind turbine blades. Expanding its cultivation is considered essential for advancing renewable energy infrastructure and supporting global carbon neutrality goals. However, balsa trees (Ochroma lagopus) grown in Xishuangbanna often develop early flowering and branching, leading to non-ideal architecture and significantly lower wood production.

In a study published in Physiologia Plantarum, researchers from the Xishuangbanna Tropical Botanical Garden (XTBG) of the Chinese Academy of Sciences have revealed the molecular mechanism behind early branching in balsa trees—a trait that limits wood production and commercial cultivation. The study identified a key gene, FLOWERING LOCUS T (OlFT-like), as a central regulator governing both flowering time and branch initiation.

The researchers compared an early-branching Indonesian variety with a late-branching cultivar from Ecuador. Using high-throughput transcriptome sequencing, they analyzed gene expression patterns in the shoot tips of both cultivars.

Genetic analysis showed that reduced expression of genes responsible for maintaining shoot apical meristem (SAM) activity was correlated with loss of apical dominance and increased branching in the Indonesian variety. In contrast, there was a marked upregulation in the expression of flowering-promoting genes.

Notably, a gene identified as OlFT-like—a putative ortholog of FLOWERING LOCUS T—was highly expressed and strongly associated with the initiation of both flowering and branching.

Furthermore, the researchers overexpressed the OlFT-like gene in a model woody plant, Jatropha curcas. They observed that the ectopic expression of OlFT-like suppressed main stem vertical growth, promoted branching, and downregulated genes that control meristem activity.

“Our study provides valuable insights for early screening of superior balsa ecotypes and for molecular breeding programs aimed at developing improved varieties with ideal architecture for higher wood yield,” said TANG Mingyong of XTBG.

The perennial balsa trees produce branches and flowers early.  (Image by QIAN Yiwen)

First published: 10 September 2025