The invention discloses an improved CTAB (cetyltrimethylammonium
bromide) method for extracting
genomic DNA of cotton. The method comprises the following steps: (1)
grinding liquid nitrogen into
powder, adding a CTAB
buffer solution, and shaking the
mixed solution in a water bath at 65 DEG C to obtain an extract solution I containing
DNA; (2) performing cooling, adding RNase A, and performing a water bath at 37 DEG C; (3) adding equal volume of a solution A, uniformly mixing the solutions and performing
centrifugation to obtain a supernatant I; (4) continuously adding equal volume of the solution A, uniformly mixing the solutions and performing
centrifugation to obtain a supernatant II; (5) adding NaAc, then adding absolute ethyl
alcohol, and performing shaking horizontally to form flocculent precipitates; (6) performing
centrifugation, removing the supernatants, washing the precipitates, removing absolute ethyl
alcohol, and performing
drying to obtain precipitated
DNA; (7) dissolvingthe precipitated
DNA and storing the DNA in a refrigerator at subzero 20 DEG C for standby application. The method has the advantages that procedures for extracting
genomic DNA of cotton leaves with the CTAB method are simplified, experimental time is shortened greatly,
DNA extraction cost is reduced,
RNA eliminating effect is improved, and the method is applicable to large-scale extraction of
genomic DNA of the cotton leaves.