Genetic variation in growth, stem straightness, pilodyn and dynamic modulus of elasticity in second-generation progeny tests of Acacia mangium at three sites in Vietnam

164 open-pollinated families of Acacia mangium from six different genetic groups were tested in three second-generation progeny tests planted at Tuyen Quang and Ba Vi in northern Vietnam and Bau Bang in the south. All trees were measured to estimate individual heritabilities and genetic correlations for growth traits, stem straightness and pilodyn in the three trials, and dynamic modulus of elasticity (MoEd) of standing trees was only assessed in Tuyen Quang. There were significant differences between families for growth traits, stem straightness, pilodyn penetration and predicted MoEd. Heritabilities of growth traits, stem straightness, pilodyn and dynamic modulus of elasticity were low to moderate (h(2) = 0.11-0.30). The coefficient of additive genetic variation for DBH, pilodyn and MoEd were moderate at age 3 or 4 years (CVa = 4.9-9.4 %). Genetic correlations between stem straightness, pilodyn and growth traits were favourable but weak, while those between growth traits and dynamic modulus of elasticity were weak and unfavourable. The substantial coefficients of additive genetic variation and significant heritabilities for all traits indicate that it should be possible to use a selection strategy that combines improvements in growth, stem straightness, and wood quality for A. mangium in Vietnam. The site-site genetic correlations between the two northern trials and Bau Bang site were low for growth traits, indicating that G x E effects are of practical importance for growth and different deployment populations will be required for different sites.