In vitro plant regeneration of indica rice varieties: Bg-360 and Bg-250

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