Abstract: Using a modified CTAB method， genomic DNA was isolated from 22 grape cultivars and their integrality were analyzed. Content and dosage of template， primer， dNTPs， Mg2+ and Taq DNA polymerase were selected by single factor five level tests and the optimum RAPD systems for grape were established. The total reaction volume was 25 μL containing 40 ng·μL-1 template DNA， 2.0 mmol·L-1 MgCl２， 0.8 mmol·L-1 dNTP， 1 U·μL-1 Taq DNA polymerase， 0.8 μmol·L-1primers. The appropriate PCR procedure was 94℃ 4 min， l cycle; 94℃ 45 s， 37℃ 55 s， 72℃ 80s， 40 cycles; 72℃10 min.

Key words: grape, genomic DNA, RAPD optimization