Balancing wood production and water use efficiency in the selection of open-pollinated families of Gmelina arborea

Abstract

Global climate crisis and severe water scarcity worldwide demand alternative genotypes that allow an adequate balance between production and water use while ensuring benefits for foresters. The genetic improvement of water use efficiency (WUE) in forest plantations could reduce water use without compromising yield. Above-ground biomass (AGB), saw-wood volume up to small-end diameter of 15 cm (V15), wood density (WD) and intrinsic WUE (WUEi) from wood carbon isotopic discrimination was evaluated in forty open-pollinated families of G. arborea grown in a tropical dry forest known as a water-limited environment, to select superior genotypes considering a balance in wood production and water use. Heritability of open-pollinated family means were moderate with values of h2f = 0.554 for AGB, h2f = 0.541 for V15, h2f = 0.608 for WD and h2f = 0.495 for WUEi. Significant genetic correlations between both WD and WUEi and production traits (p < 0.05) and a nonsignificant genetic correlation between WD and WUEi were found. Although production traits and WUEi showed moderate narrow-sense and family means heritabilities, considerable responses to selection of up to 13.7% in AGB, 15.5% in V15, 2.5% in WD and 3.0% in WUEi could be achieved from intensive selection of superior families. Our results showed that it may be possible balancing wood production and WUE by selecting open-pollinated families of G. arborea with higher V15 and WUEi. The deployment of these superior families can be used as a forest management strategy to adapt the species to future drought scenarios associated with global climate change.