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Ziziphus nummularia, a tree species of India desert has attracted attention of molecular biologists due to its tolerance to various abiotic stresses. High quality and quantity of DNA from field grown leaves is an essential requirement to carry out any studies on genomics of Ziziphus nummularia but the thick cell wall and high content of secondary metabolite such as polysaccharide, phenolic compounds, alkaloids, flavonoids, terpenoids and saponin etc. present in mature leaves of Ziziphus hamper the isolation of high quality and quantity of DNA. In the present study a simple and efficient modified cetyl trimethylammonium bromide (CTAB) protocol for isolation of good quality DNA from mature leaves of Ziziphus nummularia has been developed.

Different extraction buffers with varying concentration of CTAB or SDS, PVP and beta mercaptoethanol were used and buffer with 2.5% CTAB, 3% PVP and 0.5% beta mercaptoethanol was observed to give the best yield of 116.75 mu g of DNA per gram of tissue. The DNA thus isolated was of good quality and suitable for downstream molecular biology processes like Polymerase Chain Reaction, restriction digestion and cloning.