Comparison of Different DNA Isolation Methods from Grapevine (Vitis vinifera) Leaves

The extraction of high-quality DNA is essential for molecular analyses in grapevine, yet differences among commonly used protocols remain underexplored. This study compared two cetyltrimethylammonium bromide (CTAB)-based methods, with and without polyvinylpyrrolidone (PVP), and three commercial kits (peqGOLD Plant DNA Mini Kit, Qiagen DNeasy Plant Mini Kit, and SPINeasy DNA Kit for Plant MP) using grapevine leaves and other tissues and further validated the CTAB protocol across 34 cultivars. DNA yield, purity, and integrity were assessed spectrophotometrically and by electrophoresis, while PCR suitability was confirmed for all methods. CTAB provided the highest yields and purity at low cost, with densitometry showing approximately 70–85% high-molecular-weight DNA (>20 kb). The Qiagen kit yielded reproducible results with moderate integrity (about 40–60% HMW fraction), making it suitable for high-throughput applications. The MP kit produced high concentrations but severe fragmentation (<10% HMW fraction) due to bead-beating, while the VWR kit performed worst in yield and purity. The addition of PVP improved DNA purity in polyphenol-rich tissues but reduced yield. All protocols generated DNA sufficient for PCR amplification. Overall, CTAB was robust and cost-effective across cultivars and tissues, Qiagen offered speed and reproducibility, and MP provided high concentration at the expense of integrity.