Calli of indica rice (Oryza sativa L.) cultivar Sangyod were propagated in a liquid
culture medium containing 4.10 gL-1 modified Chu/Gamborg (NB) basal medium, 1 gL-1 Lproline,
2 mgL-1 2,4-dichlorophenoxy acetic acid (2,4-D), 1 mgL-1 1-naphthalene acetic acid
(NAA) and 30 gL-1 sucrose, maintained in shaker flasks (25±2°C, 100 rpm, under light for 27
days. Day 12 was found to be the best time for callus propagation, indicated by fresh mass
(F.M.) doubling time (td) 11.73 day-1 and the highest cell density up to 66.83 gL-1 F.M. and 4.98
gL-1 dry mass, in the exponential phase. The productivity was 2.61 gL-1day-1 F.M. and yield of
cell mass (Yx/s) was 1.08 gcellg-1
glucose F.M. The specific growth rate (μ) was 0.06 day-1 F.M.
This data can be used to choose the optimum time for repeated subculturing callus to increase
the productivity of high cell density cultures and it is an important for further study the
physiological and morphological differentiation of cell suspension culture, improving plant
regeneration systems.