Abstract
Four genotypes of Himalayan cedar were grown in vitro for assessing shoot proliferation. This experiment consist three parts. Initially, the explants (leafy and defoliated shoot-tips) of mature plants were disinfected and cultured on different basal media (LP, MS and WPM) that supplemented with benzyladenine (BA) at different concentrations for 6 weeks. Leafless explants produced the highest number of shoots and the longest shoots for four genotypes. There was no significant difference between the culture mediums and benzyladenine concentrations. In second phase, the influence of benzyladenine (2.5, 5, 10, 20 µM) and thidiazuron (TDZ) (0.4, 0.8, 1.6 µM) with combination of different auxin (NAA) concentrations (0, 1, 2, 3 µM) was determined on axillary shoot proliferation of the leafless explants of four genotypes grown on WPM. For all thidiazuron concentrations, significant differences between genotypes were detected. In general, with all genotypes, the use of 0.8 μM thidiazuron in the absence or presence of auxin (2 μM) led to the highest length and number of axillary shoots per explant, respectively. Finally, in another experiment, the following cytokinin treatments were investigated for axillary shoot multiplication of the CD1 genotype: thidiazuron (0, 0.1, 0.2, 0.4, 0.8 μM) and N6-[2-Isopentenyl] adenine (2iP) (0, 0.1, 0.2, 0.3, 0.4, 0.5 μM) in combination with benzyladenine (2.5 µM). The best results were obtained in thidiazuron (0.8 µM) with combination of benzyladenine (2.5 µM). This protocol is considered as the first successful report on culture establishment of some genotypes of mature C. deodara trees.
