Synergistic effect of cytokinins and auxins enables mass clonal multiplication of drumstick tree (Moringa oleifera Lam.): a wonder

Abstract

The synergistic effect of plant growth regulators on axillary bud proliferation for mass clonal multiplication of Moringa oleifera Lam. (vern. drumstick) has been assessed for the first time. Treatment of decoated seeds with 1% (w/v) Bavistin for 60 min, 0.33% (w/v) streptocycline for 30 min, and 0.1% (w/v) HgCl2 for 3.5 min resulted in complete removal of the surface contaminants. Maximum seed germination (89.13%) was obtained on quarter-strength Murashige & Skoog (MS) medium. Culture of nodal segments on MS + 6-benzyladenine (BA) at 3 mg L−1 resulted in multiple shoot proliferation with ~ 18 shoots per explant. All combinations of indole-3-acetic acid (IAA) + kinetin (Kn) resulted in elongated shoots, while only lower concentrations of BA (0.5 mg L−1), along with IAA (0.5 to 2 mg L−1), or Kn (0.5 to 5 mg L−1), showed significant synergy in the shoot morphogenesis. In addition, the maximum (100%) rooting efficiency was attained on half-strength MS medium supplemented with different concentrations of IAA and indole-3-butyric acid (IBA). The rooted plants were successfully established in the greenhouse for acclimatization. Clonality of the raised plants was assessed using 15 random primers of Operon® technologies (OPT and OPF series), and eight primers resulted in significant amplification with distinct, identical, and reproducible bands that confirmed clonality of the micropropagated plants. The present study provides a comprehensive analysis of the synergistic effect of plant growth regulators (PGRs) on in vitro shoot regeneration and proliferation for clonal mass multiplication disease-free plantlets, which can be utilized to maximize the yield of healthy and genetically identical plants of drumstick tree, which is considered to be a miracle multipurpose tree.