Genetic characteristics of wood properties of 14 clones of Gmelina arborea Roxb. in the South Pacific of Costa Rica

Abstract Introduction: Gmelina arborea Roxb. is planted in reforestation programs with clones to improve productivity. Objectives: We aimed to evaluate wood properties and determine the heritability of 14 clones of G. melina to establish a genetic ranking for selection. Materials and methods: The trial was established with a randomized complete block design (six blocks of six individuals of each clone of 36 months of age). Basal area and volume, tree morphological properties (diameter, bark, sapwood and heartwood) and wood physical properties (specific gravity, green density and moisture content) were estimated for each individual. Results and discussion: Growth parameters were not significantly different (P > 0.05) among the 14 clones. Clone had no significant effect on specific weight and moisture content in the genetic analysis, while tree stem height had a significant impact on all variables. The clone*height interaction was not significant for the variables studied. As for genetic control, high individual heritability values were determined only for heartwood percentage. The ranking analysis evidenced that the best clones were 1, 7, 12 and 13, positioning themselves in category 1. Conclusions: Four clones were higher regarding growth and some wood properties, showing potential for further genetic improvement of G. arborea in reforestation programs.