Author(s):
Gaspar, Maria João 
; Louzada, José Luís ; Silva, Maria Emilia ; Aguiar, Alexandre ; Almeida, Maria Helena
Date: 2008
Persistent ID: http://hdl.handle.net/10400.5/5520
Origin: Repositório da UTL
Subject(s): Pinus pinaster; age; wood density; genetic parameters
Description
This study contributes to the Pinus pinaster Ait. breeding programme, which is reaching the third generation by
adding information on wood quality of 46 open-pollinated families from a progeny trial located in Leiria, Portugal, that originated
from seed collected in a clonal seed orchard. A total of 552 seventeen-year-old trees were sampled at 2 m height.
Trends were studied from the pith outward in variance components and narrow-sense heritability (h2) of wood density
components and ring-width characteristics as well as genetic correlations between cambial ages. Mean ring density (RD),
minimum density (MND), maximum density (MXD), earlywood density (EWD), latewood density (LWD), earlywood
width, latewood width, ring width, latewood percentage, and heterogeneity index were determined using X-ray densitometry
procedures. RD had higher genetic control (h2 = 0.63), and heritability values of earlywood components (h2
MND = 0.54,
h2
EWD = 0.60) exceeded those of latewood components (h2
MXD = 0.34, h2
LWD = 0.26). Heritabilities increased with ring
number from pith for almost all wood density components, and there were high age–age genetic correlations for wood density
traits (rg > 0.98).
