Genetic correlations between wood density components in Pinus pinaster Ait.

The main purpose of this work was the determination of the genetic correlations among the density components of Pinus pinaster. The material was collected from 180 trees by the extraction of an increment core from pith to the cambium, at breast height, in a open pollinated test with 15 families at 18 years growth. The wood density components were measured using the X-ray densitometry technique. Although initially the density components of all rings were defined, in this study it was only analysed rings with a 6, 10 and 13 cambial age. The Average Ring Density is more dependent on the Earlywood components, mainly on Earlywood Density, than Latewood ones. Among all the components analysed, Earlywood ones revealed the highest and most stable genetic control, without revealing any adverse genetic correlation with regard to other components. Therefore these are the most suitable ones to be included in future selection and improvement programmes. Even though the correlation coefficients are low, Ring With is positively correlated at genetic and phenotypic level with Average Ring Density, Minimum Density, Earlywood Density and Latewood Percentage.