Clonal Variation and Genotype by Environment Interactions in Growth and Wood Density in Eucalyptus camaldulensis at Three Contrasting Sites in Vietnam

Abstract

Abstract A total of 172 clones of Eucalyptus camaldulensis were tested in three clonal tests in northern, north-central and southern Vietnam, with 32 of them planted across all three sites. At age 3-5 years, the clonal repeatabilities were 0.18-0.42 for growth traits, 0.71-0.78 for wood basic density and 0.56-0.66 for pilodyn penetration. Genotypic correlations between growth and density at the three sites were from -0.24 to 0.17, and did not differ significantly from zero. Genotypic correlations between sites were 0.32-0.56 for growth traits at age 3 years, and 0.72-0.88 for density and pilodyn penetration. Selection gains for breast height diameter at individual sites at a selection proportion of 5% were 22-32%, with minor effects on density. Selection for diameter at one site gave indirect responses in diameter at the other two sites that were only 40-60% of the gains obtainable from direct selection at those sites. This study shows that fast-growing E. camaldulensis clones can be selected in Vietnam with only minor effects on density. Selection for growth should be regionally based to maximize selection gain whereas clonal rankings for density will change little across regions.