Cassava (Manihot esculenta Crantz), a perennial vegetatively propagated shrub and a member of the family Euphorbiaceae, is adaptable to different types of soils and cultivated under temperature and rainfall conditions varying between 10°C and 40°C and between 900 mm and 2000 mm, respectively. Stem nodes of cassava, American cultivar, were treated with different concentrations of Clorox at different times (10, 20 and 30 % Clorox for 5, 10 and 15 min). The lowest significant contamination and the highest significant survival percentages were recorded with 20% Clorox for 15 min. Sterilized and survival nodal explants were cultured on MS medium supplemented with different concentrations of BA and Kin (0.1, 0.3, 0.5 and 1.0 mg L-1 from each one alone) in combination with 0.05 mg L-1 of NAA. Maximum number of shootlets per explant (5.67) was achieved on MS medium supplemented with 1.0 mg L-1 BA + 0.05 mg L-1 NAA (proliferation medium). The results demonstrated that there were not observed variations between them. These results confirmed that tissue culture technique was providing safety for in vitro propagation of cassava plant.

Neama A. Abd Alla, MSc.: Studied Agricultural sciences (vegetable crops) at Tanta University. She is working at National Research Center (NRC), Egypt. Hussein S. Taha, Ph.D, Prof. of Plant Biotechnology, National Research Center (NRC), Egypt. Mohamed E. Ragab, Ph. D., Prof. and vice Dean of Faculty of Agriculture, Ain Shams Uni., Egypt.