Abstract: The DNA quantity and purity strongly limited the digestion efficiency of restrict endonuclease. In order to find an effective method of extracting high quality total DNA from R. solani, the methods, such as CTAB-extraction, SDS-extraction, improved CTAB-extraction, glusulase-extraction and protease K-extraction were compared. The purity and yield of the DNA were determined by ultraviolet absorption spectrum. The DNA quality was also evaluated with agarose gel electrophoresis (AGE), PCR amplification, restrict endonuclease digestion and Southern blot. Results showed the protease K-extraction is most suitable for extracting genomic DNA from R. solani．

Key words: Rhizoctonia solani, total DNA, Southern blot, protease K-extraction