Influence of different treatments and techniques on rooting behaviour of Rhododendron arboreum Sm. In Indian Himalayas

Rhododendron arboreum Sm. a wild flowering tree is on the verge of extinction from natural habitat due to over exploitation of its flowers and slow regeneration rate. The objective of this research was to explore the effective method for propagation of this species vegetatively, therefore, to maintain its genetic identity and population. In this context, effectiveness of vegetative propagation methods like FRI-Wire Technique and Air Layering in combination with root promoting hormones such as Indole 3-Butyric Acid (IBA), Indole Acetic Acid (IAA) and Napthelene Acetic Acid (NAA) at concentration of 1000 ppm (ppm), 2500 ppm and 5000 ppm each were evaluated through well designed experiments. Air Layering method failed to produce roots on this species, whereas, FRI-Wire Technique showed a remarkable success for rooting in the month of April with hormones IAA and NAA at 1000 ppm and 2500 ppm concentrations and no response from IBA. Branch sizes of length 45-51 cm, when treated with 2500 ppm IAA concentration performed significantly better and produced 66.66% rooting in comparison to other treatments with the technique. (c) 2021 Ecological Society of China. Published by Elsevier B.V. All rights reserved.