Clonal Propagation of Pink Ginger in Vitro

Abstract

Fig.1.Bractaxil explant (left) and rooted shoot with basal buds (right) of A. purpurata ‘Ginoza Hybrid No. 5’ on agar medium. Until the late 1980s, there were basically five clones of red and pink gingers [Alpinia purpurata (Veill.) K. Schum.] (Criley, 1988a), with the majority of the production being the red A. purpurata (no cultivar name) and its pink cultivar Eileen McDonald. These gingers primarily are propagated by division or by rooting aerial offshoots produced in the axils of the inflorescence bracts (Criley, 1988b). In 1985, however, Janet Ginoza, a commercial flower grower on the island of Oahu, found a seed pod on a plant of ‘Eileen McDonald’ and grew 20 seedlings from it (Hirano, 1991). The suspected pollen parent was the light-pink ‘Jungle Queen’. While ‘Eileen McDonald’ produces aerial offshoots in the inflorescence, ‘Jungle Queen’ does not, and most of the progeny, which had contrasting pink bracts with darker pink margins, also did not produce aerial offshoots. Three new superior cultivars have been named and released. Their propagation is slow, however, since division of the rhizome mat is the only available method. The objective of this research was to develop an in vitro multiplication system for rapid increase of these new clones. Twenty bract axils (Fig. 1) with associated dormant buds were excised from an inflorescence of ‘Ginoza Hybrid No. 5’ in Oct. 1988 and disinfested by placing individual 0.5-cm inflorescence axis sections with the bract base and vegetative axillary bud in 0.5% sodium hypochlorite plus one drop of Tween20 (Sigma Chemical Co., St. Louis) per 100 ml of diluted solution. After 10 rein, the axis was removed and trimmed to a cube 4 mm on each side, to include the bud, and placed in 0.25% sodium hypochlorite plus one drop of Tween 20 per 100 ml of diluted solution for 15 rein, followed by a 5-min sterile water rinse. As evidenced by