In vitro field collection techniques for Eucalyptus micropropagation

A simple method was established for the collection and short-term storage of shoot material from field-grown Eucalyptus grandis and E. grandis hybrids for micropropagation. Initial studies were undertaken with plants grown outside a greenhouse, which were neither fertilised nor treated with fungicides. The method was then tested and adapted for field-grown clones. It involved collecting 35–50 mm long stems with three nodes and no leaves, spraying them with 70% (v/v) ethanol and storing them in glass bottles containing moist sterile vermiculite for 48 h. Addition of 1 g l^–1 calcium hypochlorite to the first culture medium (bud break) inhibited endogenous contamination. Multiplication yields after storage of field-grown explants were 160–264 shoots/100 explants, depending on clone. This offers an alternative, improved means for explant collection over present standard procedures of maintaining parent plants in hedges or transporting shoots to the micropropagation laboratory in buckets.