Effect of seaweed liquid extracts and plant growth regulators on in vitro mass propagation of brinjal (Solanum melongena L.) through hypocotyl and leaf disc explants

The effect of seaweed liquid extracts (SLEs) made from Gracilaria salicornia, Padina gymnospora, Padina boergesenii, Gelidiella acerosa and plant growth regulators (PGRs) were examined on in vitro mass propagation using hypocotyls and leaf disc explants of brinjal (Solanum melongena L.) cultivar Pusa purple long. For the germination bioassay, seeds germinated with 20-40 % SLEs exhibited enhanced germination. Initially, hypocotyls and leaf discs were cultured on Murashige and Skoog (MS) medium containing 6-benzylaminopurine, zeatin and thidiazuron for shoot induction. The best responding cytokinin, 6-benzylaminopurine, was employed with different auxins (indole-3-acetic acid, indole-3-butyric acid and 1-naphthaleneacetic acid) for shoot proliferation. In a second experiment, all the four SLEs (10-60 %) combined with MS medium were studied for shoot propagation. Augmented shoots transferred to half-strength MS medium and supplemented with auxins and SLEs (10-70 %) individually to induce rooting. In these experiments high rate of shoot induction (96.2 %), proliferation (6 cm) and rooting (95.3 %) was found with 20-40 % of SLEs. Well-matured plantlets were transferred to soil cups, maintained in a growth chamber for a week to control humidity and then shifted to a greenhouse. This study demonstrated that SLEs could serve as an alternative to phytohormones as they were easy to extract and gave quick and high-frequency mass propagation.