Seasonal influences on In vitro bud break in Dendrocalamus hamiltonii Arn. Ex munro nodal explants and effect of culture microenvironment on large scale shoot multiplication and plantlet regeneration

A highly efficient and cost effective protocol for rapid in vitro propagation of Dendrocalamus hamiltonii Arn. ex Munro through multiple shoot formation from nodal explants, followed by mass scale production and field evaluation, has been developed after examining the effect of season, media type, carbon source, growth regulators and transplanting media on micropropagation. Early summer (April-June) was the best period for explant collection. Among the different media (B₅, MS, NN and SH) tested, MS was found to be the best for micropropagation. A multiplication rate of about 5.6-folds with healthy cultures was achieved by the 3^rd subculture, when shoots were transferred every 3 weeks to fresh MS medium supplemented with 1.5 μM TDZ and 56.0 μM ascorbic acid. TDZ was found superior to BAP and kinetin for both axillary buds sprouting, as well as, shoot multiplication. Replacement of sucrose with table sugar during shoot multiplication did not affect the multiplication frequency. Optimal rooting of 89% was achieved on half MS medium supplemented with 25.0 μM IBA and 36.0 μM choline chloride. Regenerated plantlets were acclimatized and hardened in green house using dune sand and vermi-compost (3:1) with 79.76% success, and successfully transferred to the field with ~85% survival rate. More than 3000 tissue culture raised plantlets have been successfully transferred to approximately 7.5 hectares of land. A cost effective method of clonal propagation of D. hamiltonii with a better field survival rate has been developed.