Micropropagation of Eucalyptus camaldulensis for the production of rejuvenated stock plants for microcuttings propagation and genetic fidelity assessment

• Published in: New forests Vol. 46; no. 3; pp. 357 - 371
• Main Authors: Shanthi, K., Bachpai, V. K. W., Anisha, S., Ganesan, M., Anithaa, R. G., Subashini, V., Chakravarthi, M., Sivakumar, V., Yasodha, R.
• Format: Journal Article
• Language: English
• Published: 01.05.2015
• Subjects: Eucalyptus camaldulensis
• ISSN: 0169-4286; 1573-5095
• DOI: 10.1007/s11056-014-9465-1

Adventitious rooting, a key step in clonal propagation is affected by tree maturation. Micropropagation followed by microcuttings propagation has the potential to rejuvenate the clones thereby enhancing the rooting potential and minimize intra clonal variation. In this study, 33 superior performing Eucalyptus camaldulensis clones were propagated by rooting of stem cuttings (SCs) and micropropagation. Micropropagated plantlets were used as stock plants for microcutting propagation. Rooting of SCs and micropropagation was carried out with the coppice shoot cuttings and axillary buds respectively, obtained from approximately fourteen year old trees that had undergone one vegetative propagation cycle. The adventitious rooting recorded was significantly higher in micropropagation (24.8-100 %) and microcuttings (43-95 %) than SCs method (9.3-75.5 %). Studies on ontogeny of adventitious rooting showed the emergence of root primordium from the phloem region and root initials were noticed within 5-9 days after auxin treatment. Further, molecular marker analysis showed genetic uniformity except for two ramets, detected using inter simple sequence repeats (ISSR) markers and suitable corrective measures were taken to avoid entry of such plantlets for mass multiplication. This study demonstrates the importance of integration of micropropagation and microcuttings production for rejuvenation and mass multiplication. Although current rejuvenation and root induction treatments favored adventitious rooting, the basic mechanisms involved in rejuvenation and adventitious rooting need to be explored for hassle free industrial rooting process, consequently cost effective propagation.