Indirect regeneration from cotyledonary explants of watermelon (Citrullus lanatus) at in vitro culture

Genetic improvement by means of tissue culture and biotechnology offers qualified products by introducing recombinant genes or generating somaclonal variants with more resistance to biotic or abiotic stresses. In vitro organogenesis of different cotyledon segments of watermelon was done in medium supplemented with 0.1, 0.5, 1.5, 2.5, 3.5 and 5 mg/L BA and 0.1 and 0.5 mg/L IAA. The best regeneration was obtained for the central region of cotyledon under light condition and for hypocotyl in darkness. Regeneration with increasing BA concentration (3.5-5 mg/L) increased in the central segments but decreased in hypocotyl segments. IAA did not efficiently affect the regeneration process. The data showed that in vitro organogenesis of watermelon occurred with higher efficiency, when cotyledon segments from the proximal region were cultured in MS medium including 3.5 mg/L BA and 0.5 mg/L IAA under a 16/8h photoperiod.