Clonal tests and propagation options for natural hybrids between Acacia mangium and A-auriculiformis

Cuttings from selected clones of Fi natural hybrids between Acacia mangium (Daintree provenance, Queensland) and A. auriculiformis (Darwin provenance, Northern Territory) together with seedlings of the F-2 hybrid generation were included in a set of four trials planted at Ba Vi, northern Vietnam. At age 4 years a marked heterosis effect was observed for cuttings of F-1 hybrids. Their growth was significantly higher than seedlings and cuttings of parental species and this tendency could be maintained for the next several years. Growth of F-2 hybrid seedlings after years was intermediate between that of their parental species and segregation in their morphology was obvious. From the clonal tests, some promising F-1 hybrid clones that are fast growing, good in stem form and relatively high in wood density have been identified.