Abstract: Effects of several factors such as medium , cutting materials and plant growth regulators on in vitro culture and rapid propagation of Opuntia milpa alta Haw. were investigated. Using the Opuntia milpa alta Haw. stem as explant , a method for high frequency propagation of Opuntia milpa alta Haw. was established. The results of the experiments suggested that the appropriate medium for different culture stages were : (1) Germination of adventitious buds : MS + 6-BA 3. 0 mg/ L + NAA 0. 1 mg/ L. On this medium shoot multiplication occurred at a 82fold rate after 30 days ; (2)
Differentiation and subculture of rosette buds : MS + 6-BA 1 mg/ L + KT 0. 5 mg/ L + NAA 0. 3 mg/L ; (3) Rootage : 1/ 2 MS + NAA 0. 1 mg/ L + IBA 0. 1 mg/ L. The shoots could be directly rooted in transplantation medium (soil , vermiculite and sand in equal proportion) with up to 95 % survival .

Key words: Opuntia Mill, Opuntia milpa alta Haw., Plant tissue culture, High frequencypropagation