Early flowering induction and Agrobacterium transformation of the hardwood tree species Eucalyptus occidentalis.

Investigation of the genes controlling flowering in eucalypts is hindered by the lack of an early-flowering genotype. Induction of early flowering was studied in five provenances of Eucalyptus occidentalis Endl. sourced from throughout its geographic range. Seedlings initiated flowers from 13 weeks after sowing when grown under optimal conditions with a 16-h photoperiod. By 16 weeks, seedlings from four widely dispersed provenances had initiated floral buds, suggesting that competence to flower early is a common characteristic of the species. The different provenances displayed considerable variation in seedling growth rate. Elevated levels of CO had no effect on seedling growth rate, but were associated with delayed flowering. Transformation experiments demonstrated that E. occidentalis is susceptible to Agrobacterium-mediated transformation, in common with several other eucalypt species. E. occidentalis may be a valuable experimental species for molecular and other flowering studies in eucalypts.