PLANT CELL BIOTECHNOLOGY AND MOLECULAR BIOLOGY

In vitro techniques are an imperative approach for overcoming the abiotic and biotic stresses in Citrus macroptera Montr., a commercially and medicinally important endangered species of North-eastern India. The present investigation deals with the indirect organogenesis of this endangered species using leaf and seed as explant. The explants were cultured on Murashige and Skoog (MS) & WPM (Woody Plant media), containing 30g/L sucrose and 7g/L agar supplemented with different concentrations and combination of different phytohormones 2,4-Dicholorophenoxyacetic acid (2,4-D), 6-Benzylaminopurine (BA), 1-Naphthaleneacetic acid (NAA), Thidiazuron (TDZ). The maximum callus induction was observed from the leaf explant of Citrus macroptera on MS medium supplemented with 2,4-D (1.0mg/L), BA (1.5mg/L), and TDZ(0.5mg/L). Maximum shoot regeneration response was observed (85%) in WPM media supplemented with BA, Kinetin (KN), and NAA with (1.0), (1.0), (0.25) mg/l respectively. Rooting was optimised in MS supplemented with NAA (1.5 mg/L) with mean number of roots 0.90 ± 0.54.  The in vitro raised plantlets of Citrus macroptera were assessed using Random amplified Polymorphic DNA(RAPD) marker and the monomorphic banding pattern indicates the regenerated plantlets are genetically stable. The standardised protocol can be used to restore the endangered Citrus macroptera and can be propitious in propagating this cultivar.