In Vitro Induction and Identification of Tetraploid in Watermelon [Citrullus lanatus (Thunb.) Matsum and Nakai]

This research induced tetraploid watermelon through tissue culture. The cotyledons of a diploid mini-watermelon (A7) were treated with different concentrations of colchicine on medium for different time. The autotetraploid plants were identified basing on morphology, determination of the number of chloroplasts in stomatal guard cells and flow cytometry analysis. A stable autotetraploid material was observed. The results showed that tetraploid watermelons could be obtained under different treatments, and the highest tetraploid induction rate was up to 25 %. The most effective way was cutting the proximal cotyledons at the 7th day after sowing, then explants were cultivated on MS medium with 0.1 %(w/v) colchicine for 72 h, the adventitious shoot induction rate was 62.5 %, and multiplication coefficient was 3.6.