Abstract: The conditions for detecting tobacco mosaic virus (TMV) RNA in tobacco leave extract by RNA dot hybridization using a radioactive probe containing the cDNA of 3' terminal RNA of TMV strain OM have been studied. These conditions include the homology between the TMV strains isolated from Yunnan and Shanghai and the strain OM, the method for extracting viral RNA from tobacco leave and for adsorbing the extracted viral RNA onto nitrocellulose filter efficiently, the material interrupting the adsorption of viral RNA onto nitrocellulose filter and the hybridization of viral RNA with probe, and the speciality, sensiti-vity of the RNA dot hybridization method for detecting TMV-RNA in tobacco leave.

Key words: RNA dot hybridization