Effects of Thidiazuron (TDZ) on Direct Shoot Organogenesis of Gymnocladus assamicus: A Threatened and Critically Endangered Species from Northeast India

An efficient morphogenic potential was developed for direct shoot organogenesis of Gymnocladus assamicus, as an IUCN Red List of threatened and critically endangered species from Northeast India. This species is used as leech repellent of domestic animal, seedpod as detergent and roasted seed as a substitute for coffee and groundnut. The wild population is rapidly shrinking due to various anthropogenic pressure and poor regeneration. Therefore, the present study has been taken up for morphogenic potential through direct shoot organogenesis which is not reported. Nevertheless, cotyledonary nodal explants showed 100% responses in Murashige and Skoog (MS) medium fortified with 0.75 mg L-1 thidiazuron (TDZ) alone or in combination with 1 mg L-1 IBA, in comparison with other combinations tested. Cotyledonary node was found to be the best source of explant which produced 10.80 +/- 0.39 shoots per explant. Further, shoots were transferred to proliferation and elongation medium fortified with 0.25 mg L-1 TDZ in MS medium which produced 12.06 +/- 0.31 shoots per explant. MS medium fortified with 1.5 mg L-1 IAA showed highest root induction frequency (76%) with mean root number 2.03 +/- 0.19 and root length 3.26 +/- 0.27 cm. The micropropagated plantlets were transferred to soil after acclimatization with a 68% success rate.