Genetic parameters of red mahogany breeding populations grown in the tropics

The expansion of red mahogany (Eucalyptus pellita) plantations in the wet tropics of northern Australia has increased interest in the domestication of the species. A review of an overseas breeding population was undertaken to enhance our current understanding of genetic parameters for E. pellita, which are essential for the development of advanced-generation breeding programs. The large genetic differences between and within provenances, as well as the moderate heritability estimates for growth and form traits, imply that tree breeding can create improved breeds and reduce variability in plantation forests. Our analysis suggests that breeding value predictions of parents tested in first-generation provenance-progeny trials are less indicative of an individual's genetic merit than breeding values generated from second-generation trials. The low heritability estimate in the first generation relative to the second generation and the reduced inter-generational correlations will influence the level of genetic gain that can be realised. The implications of these findings for the management of E. pellita breeding populations and the production of improved seed for plantation forestry in the tropics are discussed.