Responses of ornamental Mussaenda species stem cuttings to varying concentrations of naphthalene acetic acid phytohormone application

Abstract

This study evaluated the rooting and sprouting responses of four ornamental Mussaendas species (Flag bush) stem cuttings to treatment with varying concentrations of 1-naphthalene acetic acid (NAA). Species evaluated include Mussaenda afzelii (wild), M. erythrophylla, M. philippica and Pseudomussaenda flava.  Different concentrations of NAA phytohormone were applied to the cuttings grown in mixed river sand and saw dust (1:1; v/v); and laid out in a 4 x 4 factorial experiment in completely randomized design (CRD; r=4). Results showed that increasing concentrations of NAA application slowed down emerging shoot bud in M. afzelii, P. flava, M. erythrophylla and M. philippica. While other species responded positively at some point to increased concentrations of the NAA applications, the P. flava showed retarding effect of phytohormone treatment on its number of leaves. However, M. afzelii, M. erythrophylla and M. philippica, showed marked boost in their number of roots (NR) with the NAA increased application. The 0.2% NAA treated cuttings gave highest mean NR (4.6 roots) per stem cutting followed by the cuttings that received 0.4% NAA treatment which gave 4.3 mean NR, all of which were significantly different (p≤0.05). In terms of species response to the phytohormone positive effect, M. philippica gave highest mean NR (6.1 roots), followed by M. afzelii and M. erythrophylla which had 3.8 and 3.4 roots per cutting respectively. Evidently, the study has contributed to the conservation and propagation of ornamental Mussaenda collections in addition to providing vital information towards domestication of the wild indigenous species Mussaenda afzelii.