Among the growth regulators, IBA had the largest effect on root formation (Figure 1(f)). The percentage of
rooted explants (100%) and the number of roots (10 - 12.5 roots/explant) produced were highest in media containing
IBA. However, IBA-induced roots (2.0 - 2.1 cm) were shorter than those obtained without using growth
regulators (Figure 1(g)). Treatment with NAA showed all the root stunted with shoot roots produced (Figure
1(h)). These observations were similar to the findings on Gentiana lutea by Mariya et al. [19] who reported high
root proliferation per explant obtained on MS medium containing 1 mg/l IBA. They also stated that in vitro
grown shoots on MS medium containing 0.5 mg/l IBA produced 3.08 roots per explant. Arun et al. [20] found
that with the Malbhog cultivar of Banana, a combination of 1.0 mg/L IBA and 0.5 mg/L IAA produced the best
rate of rooting, with 8.5 roots/ explants. They also observed that the medium supplemented with 1.0 mg/L IBA
alone induced rooting only in 66% of explants and only 6.5 roots/explant were obtained. In agreement with the
results of the present study, the lower response of NAA in promoting root formation of in vitro grown banana
explants was also reported by Arun et al. [20]. They found that the culture medium containing 1.0 mg/L NAA
was less efficient than IBA in the promotion of rooting, with the former inducing only 1.64 roots/explant. As in
the present study, Ravanfar et al. [21] found that maximum root length (2.46 cm) was attained on growth regulator-free
MS medium. The acclimatization of rooted plants in ex vitro conditions was carried out with the plants
bearing well-developed roots transferred to small pots containing soil mixtures (organic soil mixed with garden
soil 1:1). They were maintained at about 70% relative humidity in the greenhouse with 75% shading (Figure
1(i)). A survival rate 98% was achieved after 6 weeks.