The heritability of wood density components in Pinus pinaster Ait. and the implications for tree breeding

Abstract

The main objective of this work was to evaluate the genetic control of Pinus pinaster wood quality by estimating the heritability of wood density components and its age evolution. The material was collected from 180 trees by the extraction of an increment core, in a progeny test at 18 years old. The wood density components were measured using the X-ray densitometry technique. The highest and most stable age heri- tability values were obtained by the earlywood components (minimum density and earlywood density), followed by the average ring density. The latewood percentage, ring width and heterogeneity revealed middle values, while the latewood components (maximum density and latewood density) always presented the lowest and most unstable heritability values. Thus, it was concluded that, amongst all components, the earlywood density mostly depends on genetic effects, and could be used in future selection and tree breeding programs to improve wood quality. The inclusion of the latewood components in the selection criterion will not give any significant genetic advantage.