An improved, rapid, reproducible, and simple protocol
has been developed for somatic embryogenesis in banana
cv. ‘Grand Naine’ using explants derived from actively
growing multiple shoot cultures. Many restrictive factors remain
in banana embryogenesis such as long duration,
unpredictability, and a high degree of genotype dependence.
In the present study, we used split shoot tips from 4-wk-old
cultures as explants. Somatic embryos were induced in 15 d
directly in Murashige and Skoog (MS) medium supplemented
with different combinations of 0–8.28 μM picloram and 0.22–
4.44 μM 6-benzylaminopurine (BA) without callus formation.
Maximum embryo induction (100%) occurred when
4.14 μM picloram and 0.22 μM BA were used. Conversion
of somatic embryos into plantlets occurred sporadically (2–
3%) in MS medium containing α-naphthalene acetic acid
(NAA; 0.53–2.68 μM) together with BA (2.22–44.39 μM), or
thidiazuron (4.54 μM) plus glutamine (200 mg/L). This protocol
is far superior to those already reported for fast and high frequency
induction of somatic embryo. In liquid agitated culture,
individual embryos separated easily and produced a large number
of secondary embryos within 10 d which, upon transfer to
filter paper overlaid on MS liquid medium supplemented with
4.44 μM BA, resulted in conversion (3%) into plantlets.