Development of appropriate <i>in vivo</i> technique for rapid field multiplication of plantain (Musa AAB) using coconut (<i>Cocos nucifera L.</i>) water and indole-3-acetic acid

Abstract

Plantain production in Ghana is challenged with inadequate healthy and uniform sized planting materials for cultivation. In vitro and rapid field multiplication techniques of plantains have been developed to overcome the problem of obtaining many vigorous and uniform suckers free from pest and diseases. However, in vitro techniques require expensive equipment and expertise that are unavailable to most plantain farmers in Ghana. Therefore, an appropriate and inexpensive technique has to be developed in vivo
to increase the multiplication rate of plantain planting materials. This study investigated the effects of coconut water (CW) alone or in combination with varying concentrations of auxin (indole-3-acetic acid, IAA) on axillary bud initiation, growth and development of plantain (cv. Asamienu). Coconut water from fully matured dried fruits (13 months old) was supplemented with three different indole-3-acetic acid concentrations, 10-4 M, 10-3 M, and 10-2 M to produce five different coconut water : IAA ratios (v:v), viz: 8:0, 6:2, 4:4, 2:6, 0:8. Distilled water was used as control. These treatment solutions were then injected into the base of developing suckers of plantain. Three weeks after injection treatments, the highest number of well differentiated buds was obtained from 2 ml coconut water and 6 ml of 10-2 M IAA (2:6 ratio). Eight ml of coconut water alone (8:0 ratio) also produced the highest number of fully differentiated plantlets. One month after the application of the bud manipulation technique, the highest number of additional welldifferentiated axillary buds and fully developed plantlets were produced with 2 ml coconut water plus 6 ml 10-2 M IAA and 4 ml coconut water plus 4 ml 10-2 M IAA,
respectively. The study generally showed that treatments with coconut water from fully matured dried fruits alone produced the largest and the most vigorously growing plantlets. On the other hand, coconut water from fully matured dried fruit combined with IAA induced significant proliferation of axillary bud and shoot formation of plantain significantly over the control treatment. These findings  demonstrated the potential of using coconut water from fully matured dried fruits alone or in combination with IAA at ratios of (2:6) and (4:4) to improve the multiplication rate of plantain planting materials.

Key words: coconut water, indole-3-acetic acid, plantain, axillary buds, multiplication rate, in vivo