The effect of different hormone concentrations and dark pretreatment on adventitious shoot regeneration in snake melon (Cucumis melo var. flexousus)

Explants consisting of the proximal part of cotyledons from 7 day-old seedlings, germinated under dark and light conditions, were cultured on MS media containing different concentrations of BA (0, 0.5, 1.0, 2.0 mg/l) and IAA (0, 0.25, 0.5, 1.0 mg/l). Germination ratio of the seeds under both light and dark conditions was found as 66.8 %, but shoot formation ratio obtained from the seeds germinated under dark condition was higher than the seeds germinated under light condition. The highest frequency of adventitious shoot regeneration (42.8 %) was obtained on MS medium with 1.0 mg/l BA+ 0.25 mg/l IAA from the seeds germinated under dark condition. 1.0 mg/l BA+ 0.5 mg/l IAA (34.8 %), 1.0 mg/l BA(32.8 %), 2.0 mg/l BA+ 0.25 mg/l IAA (12.8 %) and 2.0 mg/l BA+ 0.5 mg/l IAA (7.1 %) resulted in a lower shoot regeneration frequency. In the case of the seeds germinated under light conditions, the maximum frequency of adventitious shoot regeneration from cotyledon explants (2.8 %) was achieved on MS medium with 1.0mg/l BA+ 0.25 mg/l IAA. Hormonal supplements of 2.0 mg/l BA (1.8 %) and 2.0 mg/l BA+0.5 mg/l IAA (1.4 %) resulted in a much lower shoot regeneration frequency.