A Pinus pinaster Ait. progeny trial involving 46 open pollinated families was
established at two locations in Portugal (Leiria and Escaroupim). Height, diameter, Pilodyn and
stem characteristics (straightness, branch size and number of whorls) were assessed at age 5
and 12 and were used to estimate variance components, heritability, phenotypic and genetic
correlations between traits.
Estimates varied considerably between the two sites. However, this study indicates that the
heritability for height followed the general pattern of increasing with the age of the trees. A
strong and favourable genetic correlation between the stem form and branching was also
found. Heritability of Pilodyn was very low, suggesting that measurements taken at age 12
were not a reliable measure of wood density, probably due to the high proportion of juvenile woo
