Abstract:
Rice is the single most important crop in Sri Lanka which needs to improve the yield in
order to combat with demands of increasing population. The improvement can possibly be
achieved by genetic manipulation and it is highly dependent on the use of in vitro
techniques. Callus induction and plant regeneration are prerequisites in in vitro techniques
for the use of biotechnological approaches for rice improvement through genetic
transformation. In this study the callus induction and plant regeneration were done with
Bg-360, Bg-250 Sri Lankan rice varieties on modified N6B5 medium. High variability in
callus induction and plant regeneration was observed among the cultivars. The candidate
variety Bg-250 showed highest (90%) callus induction frequency than that of the other
candidate variety Bg-360 (41.25%). Highly significant regeneration difference was
observed in partially desiccated calli of Bg-360 in comparison to non-desiccated Bg 360
calli. It took 5-6 weeks for callus to regenerate into complete plants. The Bg-360 produced
16 and Bg-250 produced 13 plantlets per callus, with the regeneration frequencies of
42.42% and 95% respectively. The shoots regenerated from calli were successfully
transferred to rooting medium for one week and plantlets with healthy roots were
established in the soil. The results suggested two rice varieties used, Bg 250 showed the
highest regeneration efficiency and after desiccation Bg 360 could successfully
regenerated into complete plant. In conclusion, with standardized rice regeneration
protocol, Bg 360 and Bg 250 are good candidates to transform with Arabidopsis STH2
gene in order to improve their yield
