Clonal multiplication of tree species in the Thar desert through tissue culture

Abstract

A few hardwood trees were successfully propagated in the natural environs of the Thar desert by tissue culture; they included Prosopis cineraria, Zizyphus mauritiana, Tecomella undulata, Aegle marmelos, Eucalyptus viridis and Eucalyptus sideroxylon. Natural propagation of some of these plants is poor and vegetative propagation methods have failed. Elite strains of these plants were selected for multiplication through tissue culture. Explants (axilliary and terminal buds), cut into 8–10 mm size were placed on Murashige and Skoog's (MS) medium, supplemented with organic and inorganic salts. Explants on the media were maintained at 25±2°C and 1500–3000 lux light intensity. Various concentrations of auxins (0.05-5.0 mg l −1 IAA, IBA, NAA and 2,4-D) and cytokinins (0.05−6.0 mg l −1 Kinetin and BAP) were used. Each plant was specific in its requirement for auxin and cytokinin for production of multiple shoots. Regenerated shoots were subcltured for further multiplication on half-strength MS medium. Shoots were excised and subcultured on White's basal and 1 2 or 1 4 strength MS medium with various concentrations of NAA/IBA for rooting using a paper bridge platform or on agar medium (0.5−0.6% agar). Complete roots developed within four to six weeks. Fully developed plants were removed from the medium, washed thoroughly with water, and transplanted to earthenn pots containing a sterile mixture of soil and vermiculite (1:3). Pots were covered with polyethylene bags for the first few days. Plants were nurtured under semicontrolled temperature (25–32° C) and light (3000 lux) conditions in the glasshouse. Potted plants were grown in the glasshouse for 40–70 days before they were finally transfered to the field to test their performance.