Optimized system for plant regeneration of watermelon (Citrullus lanatus Thumb.)
The objective of this study was to establish an efficient and reproducible in vitro plant regeneration for Citrullus lanatus cv. Zaojia. To achieve optimal conditions for adventitious shoot induction, five explants (entire cotyledons, distal cotyledons, proximal cotyledons, cotyledonary node A and cotyledonary node B) were tested on MS medium supplemented with different concentrations and combinations of growth regulators (0 to 0.2 mg/L IAA and 1.0 to 5.0 mg/L BA), the results showed that entire cotyledons cultured in MS + BA (2.0mg/L) + IAA(0.2mg/L) achieved the highest regenerated rate (89.67%) and the optimal protocol screened in this experiment had 7.69 ± 0.10 shoots per explants. Adventitious shoots were able to elongate both on MS medium with 0.2 mg/L KT and 0.2 mg/L NAA; IBA 0.3mg/L was found to be effective in the production of root. Acclimatized plantlets transferred to pot resumed growth, and their stems and leaves elongated and expanded in one month.
Key words: Watermelon (Citrullus lanatus Thumb.), optimized system, regeneration, cotyledon explants, cotyledonary node.