Abstract:
This study was concerned with the micropropagation of stevia by tissue culture, in order to
establish an efficient and reproducible in vitro propagation technique. The explants,
shoot tip, leaf base with petiole and nodal segment of stevia were cultured on MS
medium supplemented with 5 different concentrations (0.0, 1.0,2.0,3.0,4.0 and 5.0
mg/L) of BAP for shoot proliferation and elongation of stevia. Nodal segment
performed best and BAP 3.0 mg/L was found optimum for shoot proliferation and
elongation. The experiment with various cytokinin showed that BAP applied
alone was the most effective cytokinin for stevia When BAP was used in
combination with 2ip and KN, the number of shoot and their length were
decreased, whereas the highest number of shoot (8.0) and length (7.8 cm) was
found with the application of BAP 3.0 mg/L. The best response towards root
induction was achieved on Yi MS medium supplemented with 1.5 mg/L NAA.
Callus induction was observed, the best on MS medium containing 3.0 mg/L of 2, 4-D.
Callus (0.3g) explanted on MS basal medium supplemented with different concentration
and combination of NAA and BAP (Ti-control, T2-l.O mg/L BAP + 0.5 mg/L NAA, T3-
l.O mg/L BAP + 1.0 mg/L NAA, T4- 1.0 mg/L BAP + 2.0 mg/L NAA, Ts-2.0 mg/L BAP
+ 1.0 mg/L NAA, T6-2.0 mg/L BAP + 2.0 mg/L NAA) to observe their effect on the
subsequent growth and development of initiated stevia plantlets at 30, 60 and 90 days after
inoculation (DAJ). However, T2 (1.0 mg/L of BAP + 0.5 mg/L ofNAA) gave the best
result (8.9 shoots/ explant) in respect of the highest shoot proliferation and the highest
number of root formation was 9 roots /shoot under T3 (1.0 mg/L BAP + 1 mg/L NAA)
treatment at 90 days after inoculation (DAI). The regenerated plantlets were successfully
established into the pots after proper hardening. The cocodust medium was found the
best substrate for ex vitro establishment of stevia.
