In the regeneration of sweet potato, correct
hormone combination ratio is one of the critical
factors to consider in obtaining high regeneration
efficiency [5,6]. Plant hormones or plant growth
regulators (PGRs) in combination with other
nitrogen sources make up the culture medium
that supply all the essential mineral ions required
for plant growth and development. Plant
hormones have a profound effect on the
morphology of the tissue developed from the
explants as they can enhance not only the
growth of some cultured slow growing tissues,
but also determine the development pathway of
the plant cells. In addition, it has been observed
that plant hormones or pytohormones play an
important role on the possibility for
organogenesis or somatic embryogenesis to
occur in culture [7], and the most frequently used
PGRs in plant regeneration are auxins and
cytokinins or their synthetic analogues. Studies
have shown that the rate of proliferation of the
root and shoot system are determined by the
level of combination of auxins and cytokinins [8],
also the type of culture established is determined
by the ratio of auxins to cytokinins, and a correct
phytohormone constitution ratio is necessary to
optimize regeneration of plants [9]. Hence, the
need to investigate the effect of combination of
different concentrations of α-naphthaleneactic
acid (NAA) at 2 mg/l of 6-benzylaminopurine
(BAP) application, for optimal regeneration of
sweet potato.