De novo adventitious root formations in mini-cuttings of Azadirachta indica in response to different rooting media and auxin treatments

Abstract

Neem (Azadirachta indica A. Juss) is a multipurpose Indian tree important to local economy. Conservation of the genetic resources of neem is essential for the adaptability of this tree species to projected climate change impacts. Here, the effect of type and concentration of auxins in different rooting media on adventitious root formation (ARF) in mini-cuttings of Azadirachta indica is depicted. Three different rooting media (i.e., sand, vermiculite and soil) were used, and the experiment was established using three types of auxin (IBA, IAA and NAA) and 6 concentration treatment combinations (100, 250, 500, 750, 1000 and 1500 mg l-1), in a complete randomized block design (CRBD). Significant effects of different auxin types, concentration treatments and rooting media on adventitious root formation of neem mini-cuttings were observed. Mini-cuttings were assessed for rooting percentage, number of roots, root length and number of leaves. IBA resulted in higher rooting percentage (90%), number of roots (149.56), root length (14.83 cm) and number of leaves per rooted mini-cuttings (12.78), when growing in sand. The determination of proper rooting protocols and the use of mini-cuttings were proved important for improving mass propagation of A. indica.