Studies on the effect of genotype and explant type on callogenesis and organogenesis in indica rice

The purpose of the research study is to select the best rice explant and variety for Agrobacterium mediated genetic transformation studies. In vitro callus induction and regeneration frequency of two explants i.e. immature embryo and media supplemented mature grains of 9 rice varieties (Oryza sativa L.) was investigated by culturing explants source on N/sub 6/ with 2, 4-D at 2 mg/l for callus induction. Results indicated that mature seed explant produced significantly high number of calli as compared to immature embryo. Two types of calli were distinguished, designated as type-I calli and type-II calli. Regarding the quality of callus, type-I calli (produced from scutellum of mature grains) which were embryogenic produced higher plant regeneration frequency than type-II calli which were non-embryogenic. Mature-seed scutella calli and immature embryo-derived calli (after three weeks of culture) of rice varieties were transferred on regeneration medium i.e., MS salts and vitamins, 3% sucrose, 3% sorbitol, 2 g/l casine hydrolysate, NAA 1.0 mg/l, kin 2.5 mg /l and BAP at 0.5mg/l. The highest regeneration capacity was observed in DR-83 from mature seed derived calli followed by Basmati 385. After hardening the plantlets were transferred to soil. (author)