Optimizing Growth Regulators for Micropropagation of Industrially Adaptable <i>Eucalyptus</i> Hybrids

Abstract

<i>Eucalyptus</i> is one of the highly economic tree species in the developing countries like India. In the present investigation, experiments on optimizing plant growth regulators in the micropropagation of promising inter specific <i>Eucalyptus</i> hybrid clones namely TNPL 191(<i>E. camaldulensis</i>× <i>E. teriticornis</i>), TNPL 192 (<i>E. camaldulensis</i> × <i>E. pellita</i>) and intra specific hybrid clone TNPL 193 (<i>E. camaldulensis</i>× <i>E. camaldulensis</i>) were conducted, following standard protocols developed for <i>Eucalyptus</i>. The results showed that the BAP concentration of 0.50 mg L<sup>-1</sup> for bud induction, IAA concentration of 3.0 mg L<sup>-1</sup> for shoot elongation and IBA concentration of 1.0 mg L<sup>-1</sup> for rooting of all these clones were found optimal. However, these three hybrid clones responded differently to the concentration of BAP at shoot proliferation stage. While the hybrid TNPL 191 showed maximum shoot proliferation rate at the concentration of 0.2 mg L<sup>-1</sup> of BAP, the hybrids TNPL 192 and TNPL 193 showed highest response at 0.15 mg L<sup>-1</sup>. All the <i>in vitro </i>rooted plantlets were acclimatized successfully to the prevailing natural environment. Thus, the protocols developed with respect to optimizing the plant growth regulators can be adapted in large scale micro propagation of inter and intra specific <i>Eucalyptus</i> hybrid clones.