Indirect Organogenesis of Tagetes erecta L. via Hypocotyl Explant

Mexican marigold (Tagetes erecta L.) is an annual flower that is sensitive to cold. Seasonal flowers due to their numerous varieties of colors are very important in the landscape design. In order to mass propagate this species, the techniques of plant tissue culture was applied. In this study, four experiments including seed germination at different concentrations of MS medium in the dark and light conditions, callus induction of hypocotyl, regeneration from callus and root formation in different concentrations of plant growth regulators were carried out in a complete randomized design with 3 replications (10 samples). The results showed that the highest percent of seed germination occurred in full strength of MS medium in the light condition (90.00%). The seed germination was significantly higher in the light compared to the dark condition. Hypocotyl explant in MS medium in combination with 1.0 mg.L-1 NAA + 0.1 mg.L-1 BAP produced the highest bulk of callus (1.86 g). The highest regeneration frequency (93.33 %), themaximum number of multiple shoots (6.33) and the maximum shoot length (1.90 cm) was obtained on MS medium supplemented with 3.0 mg.L-1 BAP in combination with 0.3 mg.L-1 IBA. 933.3% of the micro-shoots were rooted on MS medium supplemented with 1.5 mg.L-1 NAA. In conclusion, the hypocotyl explant could be used to achieve an optimal micropropagation protocol for Tagetes erecta.