Growth of triploid and diploid Acacia clones in three contrasting environments in Viet Nam

ABSTRACT

We assessed the growth and adaptability of triploid acacia clones in comparison with commercially planted diploid clones of the same taxa to age three years at three contrasting sites in north, central and south Viet Nam. Application of phosphorus fertiliser at planting gave a growth response only in the trial in central Viet Nam. One triploid Acacia hybrid (Acacia auriculiformis × mangium) clone was constantly the best performer in all sites, achieving mean annual increments at three years of 30.1, 26.6 and 32.1 m³ ha⁻¹ in northern, central and southern Viet Nam, respectively. Two other triploid hybrid clones outperformed the diploid controls in southern Viet Nam. A single triploid A. auriculiformis clone and two diploid clones of this species grew much more slowly. Triploid Acacia hybrid clones had a lower incidence of Corticium salmonicolor (pink disease) and Ceratocystis disease symptoms than did diploid hybrid clones. The wind-firmness of triploid Acacia hybrid clones was comparable with or better than the diploid hybrid clones. Triploid breeding offers a promising new pathway in the development of improved Acacia planting material.

KEYWORDS:

• Acacia hybrid
• ploidy
• growth rate
• disease
• wind-firmness

Acknowledgements

We thank Mr Ha Huy Nhat, Mr Duong Hong Quan and Mr Do Thanh Tung for data collection, Dr Nguyen Van Bich for the examination of soil profiles and Dr Daniel Mendham for the LAI analysis software. Dr David Bush provided helpful advice on statistical analysis and Drs EK Sadanandan Nambiar, Rod Griffin and Nguyen Duc Kien made helpful suggestions for improving the manuscript.

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

This study was funded by the Ministry of Agriculture and Rural Development, Viet Nam. Support from the Crawford Fund facilitated the participation of Christopher E. Harwood in this study.