The study was to examine the optimization of conditions for the growth of Dendrobium
friedericksianum Rchb.f. seedlings in aseptic culture. It was found that Vacin & Went was the
optimal medium for the growth of the orchid. The orchid seeds in the liquid medium before
transfer on solid medium for 1 month had 4 days faster germination than the cultivation on the
solid medium, although the two patterns of cultivation were non significant in aspect of average
dry weight. IBA and 2,4-D at 0.15 mg/l were the best of growth regulators and concentration
for stimulating growth of this orchid significantly, right across NAA and kinetin were inhibit
growth significantly. But BAP was not affect to growth and development of orchid, even
though it was used with 2,-4-D. Besides 2,-4-D affects to orchid development in aspect of
biomass, height of shoot and number of root, but not affect to the number of shoot and length of
root. The cultivation of orchid seedlings under the conditions of various temperatures and light
intensities showed the highest fresh weight on the average at 20 oC and 4000 luxs. However, the
range of the light-exposed times at 12, 14 and 16 hours per day were not significantly affected
to the total fresh weight.