REGENERATION FROM MATURE SCUTELLUM EXPLANTS OF RICE VARIETY IR64 (Oryza sativa L.) THROUGH DIRECT AND INDIRECT ORGANOGENESIS

An efficient protocol was developed for direct and indirect regeneration from mature scutellum explants of rice (Oryza sativa) variety IR64. Mature dehulled surface sterilized seeds were placed on Murashige and Skoog’s basal medium for germination. Scutellum was excised from aseptically grown, five days old seedlings for callus induction. Scutellum explants formed high quality yellow calli. The callus induction percentage ranged from 60-98%. The highest frequency of callus induction was observed in MS basal medium containing 3.0 mg L-1 2, 4-D. In the presence of BAP, the mean percentage of regeneration ranged from 17.5 to 67.5% with mean shootlet of 10 per callus. Both the frequencies of green shoots and the number of shoots formed per callus were high in the presence of 2.5 mg L-1 BAP. In direct regeneration, MS basal medium supplemented with 1.5 mg L-1 TDZ proved to be highly beneficial for germination of seeds and development of multiple shoots (57.2 shoots). Thick, white and fibrous roots were produced in MS medium containing 0.75 mg L-1 NAA. Shoots derived from direct regeneration produced greater number of roots (18.7) and longer roots (11.7 cm). The in vitro regenerants grew well and did not show any detectable variation in morphology and growth characteristics. Plants regenerated in vitro were successfully established in soil. Scutellum explants from mature seeds of IR64 could be used for molecular breeding.