Cytokinin concentrations for optimal micropropagation of Corymbia torelliana × C. citriodora

Hung, Cao Dinh; Trueman, Stephen J.

Cytokinin concentrations for optimal micropropagation of Corymbia torelliana × C. citriodora

2012

Hung, Cao Dinh | Trueman, Stephen J.

Summary The eucalypt Corymbia torelliana × C. citriodora is grown in subtropical Australia, India and Brazil, but plantation establishment has been limited by inadequate seed supply and low amenability to propagation using conventional cuttings. We have recently developed tissue culture methods for propagation, storage and distribution of this hybrid, using low to moderate concentrations (0–2.2μM) of the cytokinin benzyladenine (BA) for proliferating shoots in vitro. In this study, we determined the effects of higher BA concentrations (2.2–17.8μM) on shoot proliferation and the subsequent conversion of shoots into plantlets in five full-sibling C. torelliana × C. citriodora families. We found that 4.4μM BA provided consistently high shoot proliferation in all families (137 ± 46 to 858 ± 175 shoots from each seed in 21 weeks), complete survival of clones (100%), very high conversion of shoots into plantlets (91 ± 4% to 99 ± 1%) and excellent formation of adventitious roots (3.6 ±0.1 to 4.5 ± 0.1 roots per plantlet). This method will allow simultaneous archiving and testing of C. torelliana × C. citriodora germplasm in the laboratory, nursery and plantation as part of a clonal forestry or vegetative family forestry program.

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