In vitro flowering of cultures from a hybrid of Cymbidium goeringii and C. hybridium

Wild-type female spring orchid (Cymbidium goeringii) was crossed with male Cymbidium hybridium. Over eight hundreds protocorm clones were obtained from hybrid offsprings. Among them,oneprotocormclone was identified to differentiate visible floral buds two months after subculture in vitro (Plate I). The protocorms and shootsderived fromthis clonewere furtherused in studying the effects of abscisic acid (ABA) and paclobutrazol (PP333) pretreatment as wellasdifferentconcentrations of 6-benzyladenine (6-BA) on floral bud differentiation. The optimum combination of hormones in floral bud induction was 6-BA 1.0 mg/L and NAA 0.1 mg/L, and total frequency of floral bud formation was up to 31% (Table 1). The optimum length of shoots used infloralbudinduction was 1–2 cm,and thefrequency of floral bud formation was 19% (Table 1). The increase in total frequency was not significant in floral bud induction from protocorms and shoots with length of 1–2 cm or 2–4 cm cultured on MS medium containing 6-BA 1.0 mg/L and NAA 0.1 mg/L after pretreatment on MS medium supple- mented with ABA 0.5 mg/L and PP333 0.5 mg/L for 35 d (Table 2).