Abstract of a paper based on work funded in part by the Australian Flora Foundation.

Micropropagation of selected ornamental hybrids of Eucalyptus erythronema x E. stricklandii
P. Glocke1, K. Delaporte1, G. Collins1, and M. Sedgley2
1. Discipline of Wine and Horticulture, The University of Adelaide, Waite Campus, P.M.B. 1, Glen Osmond, SA 5064, Australia
2. M. Sedgley (Author for correspondence), Faculty of the Sciences, University of New England, Armidale, NSW 2351, Australia (email: margaret.sedgley@une.edu.au)
Australian Plants (2006) 23: 301-305  Grant details

Abstract
Research into tissue culture propagation of eucalypts has focussed mainly on forestry species, with further investigation required to adapt these methods for ornamental varieties. The objective of the research was to identify a suitable method of introducing ornamental hybrid eucalypts of Eucalyptus erythronema x E. stricklandii into culture for clonal propagation via the tissue culture methods of micropropagation and organogenesis. Initiation into culture of explants from field grown hybrids was difficult, compared to explants from hybrids grown in the glasshouse, due to greater contamination rates and higher levels of explant browning and death from the field grown hybrids. In addition the explants from field grown hybrids were difficult to sustain in culture and very slow to produce axillary shoots. In contrast nodes of glasshouse grown hybrids were successfully initiated and multiplied in culture, using the following protocol: shoot multiplication on 2 µM zeatin; rooting medium consisting of 1/2 WPM, 20 µM IBA, for 1 week in the dark; subculture to 1/2 WPM, 1.5 gl-1 activated charcoal, and returned to 16 hr light at 75 µmoles m-2 sec-1. Organogenesis was not achieved with any of the hybrids. Future work should aim to reduce explant losses on initiation into culture, and improve axillary shoot growth and shoot organogenesis, by aiming to improve stock plant vigour by management of hybrid plants under controlled glasshouse conditions. Work is currently proceeding on grafting techniques for E. erythronema x E. stricklandii and other eucalypt hybrids within the breeding programme. This is the first report of successful micropropagation for an ornamental hybrid eucalypt.