Abstract:
The present research work was carried out in Biotechnology laboratory of the
Department of Biotechnology. Sher-e-Bangla Agricultural University. Shcr-e-Bangla
Nagar, Dhaka- 1207 from the period of January 2014 to December 2014 to evaluate
the effects of different plant growth regulators in in vitro on shoot proliferation and
root lbrmation and finally to develop a viable micropropagation protocol in Stevia
(Stevia rehaudiana) using shoot tip and nodal segments as explants. Explants was
inoculated in MS (Murashige and Skoog) media supplemented with the
Benzvladenine (BA) and Kinetine (KIN) for direct shoot formation. Combination of
BA and Indolebutyricacid (IBA) as well as combination of KIN and IBA were used in
MS medium for indirect shoot formation via callus induction. The highest percent of
shoot induction (83.42%) obtained on 2.0 mg/L BA and the minimum days to shoot
induction (10.6) were also obtained on 2.0 mg/I.. BA. The highest 10.8 shoots and
17.2 leaves per explants also observed in BA 2.Omg/L. But maximum average length
of shoots per explants (3.94 cm) were reported from media containing 1mg/I. KIN. Highest callus induction potentiality (83.58%) was observed in 2 mg/L BA+1.5 mg/L
IBA The minimum days to callus induction (13.4) were recorded in 1.0 mg/L
KIN+I.5 mg/L IBA but the minimum days to shoot induction (9.6) from callus were
recorded in 2.0 mg/L BA+1.5 mg/L IBA. Righest percent of root induction (78.18%)
with 7.2 roots per explants and minimum 12.6 days to root induction were noticed on
1.0 mg/I. IBA. The combined ellèct on percent of' root induction was highest
(76.92%) in the treatment of 1.0 mg/L KIN t 0.5 mg/L IBA. The same treatment
showed minimum days (13.4) to root induction and maximum number of roots per
explants. In acclimatization 90%, 80% and 80% survival rate were recorded in growth
cabinet, shade house and field condition respectively. In vitro regeneration technique
was found to be very effective and promising niethod in the proliferation of Stevia and
this method can be used 11w large scale production of disease free and quality planting
material.
