No statistically different results were obtained during the initiation stage of GGB when explants received different low dosages of 2ip (Table 1). But the GGB production was gradually decreased under increasing levels of 2 ip, which implicated a possible inhibitory effect of this cytokinin. Furthermore under the same experimental design, the inclusion of BA in the combinations had a much stronger inhibitory effect, which significantly reduced GGB production even for the lowest level (2.22มิวM) of BA application. The addition of synthetic BA during the initiation stage seemed more harmful than the application of 2ip, perhaps because 2ip is a naturally produced PGR in ferns (Auer, 1997). Our recommendation for a better GGB initiation is to use 5.37 มิวM NAA as the sole PGR without cytokinin (Table 2). Wee et al. (1992) reported that they obtained direct sporophyte regeneration (not via GGB initiation from young fronds of two Platycerium species using this level of NAA, which verified our conclusion.