Combined effect of NAA and BAP on prococorm like bodies (PLBS) derived plantlets production for commercial propagation of dendrobium sonia orchid

Abstract

The experiment was conducted to find out the optimum concentration and combination of plant growth regulators (PGRs) and their effects on in vitro growth and development of Dendrobium Sonia orchid. The experiment was caried out at the USDA Biotechnology Laboratory, Department of Biotechnology, Bangladesh Agricultural University, Mymensingh during the period from February 2009 to May 2010. The experiment was laid out in Completely Randomized Design (CRD) with five replications. Protocorm-like bodies (PLBs) were inoculated as explants on half MS medium supplemented with four levels (0.0, 0.5, 1.0, 2.0 and 4.0 mgL-1) of Naphthalene acetic acid (NAA) and 6-Benzylaminopurine (BAP) independently to proliferate and multiply the PLBs. Then, these multiplied PLBs were cultured on different concentrations and combinations of NAA (0.0, 0.5, 1.0, 2.0 and 4.0 mgL-1) and BAP (0.0, 0.5, 1.0, 2.0 and 4.0 mgL-1) for the growth and development of Dendrobium Sonia plantlets. The maximum fresh weight of PLBs (3.5 g), the highest percentage of regenerated plantlets (95%) was obtained from the combination of 0.5 mgL-1 NAA + 0.5 mgL-1 BAP. At the same time, maximum number of shoots (6.40) as well as length of shoot (4.82 cm) and fresh weight of single shoot (0.414 g) was also achieved at this combination. Similarly, the highest number of leaves (6.00), longest leaf (2.36 cm) and width of leaf (0.78 cm) was observed from 0.5 mgL-1 NAA + 0.5 mgL-1 BAP. Moreover, the treatment combination, 0.5 mgL-1   each of NAA + BAP was found to be the best for producing maximum number of roots (6.40), length (2.82 cm) and fresh weight of roots (0.141 g). In contrast, higher concentration of 4.0 mgL-1 NAA + 4.0 mgL-1 BAP combinations showed poor results for all parameters. Bangladesh J. Agril. Res. 50(1): 39-48, March 2025