Micro-cloning of an economic rattan palm Calamus thwaitesii for eco-restoration programme

Abstract

Axillary shoots were induced from shoot tip of Calamus thwaitesii suckers on Murashige and Skoog medium supplemented with 0.4 mg/L N6-benzylaminopurine and 0.1 mg/L each of thidiazuron and α-naphthaleneacetic acid (NAA). The shoots initiated were subcultured to fresh media of the same composition for shoot multiplication and multiplied shoots were transferred to half strength MS hormone-free media for shoot elongation. The elongated shoots (∼5cm) were then re-cultured to the media supplemented with 3.0 mg/L indole-3-butyric acid/4.0 mg/L NAA to raise plantlets which were subsequently analysed for genetic fidelity using inter simple sequence repeat markers. Out of 183 bands scored, 178 bands were monomorphic indicating 97.2% similarity. The observed low level of polymorphism between genotypes supports genetic consistency of these micro-clones that are likely to be genetically true to their parental origin. The clones thus obtained were hardened in the specially fabricated mist house at 29 ±2°C and 80±5% relative humidity for 3 months followed by shifting to green house for another 3 months of nursery establishment. The established plants when reintroduced to the selected forest segments of the Western Ghats, Kerala (India) showed 79.3% survival rate after 2 years of field transfer. The viable and highly reproducible in vitro cloning protocol demonstrated here for the first time can be used for the production of elite female clones for aforestation activities and sustained delivery of high quality raw materials to cane processing units for strengthening cane industry.