Abstract

The regeneration protocol for rice plants from callus culture obtained from dehusked and sterilized whole rice seeds (caryopses) of a popular Nigerian local cultivar Suakoko 8, and a NERICA cultivar FARO 55 is described. Utilizing a modified Nippon Barre medium (NBm) consisting of: Macro N6, Micro B5, Fe-EDTA, B5 vitamin and 30 mg/l of locally produced St Louis® sugar (to save cost) supplemented with casein hydrolysate and proline, and with cytokinin and auxin hormones (ratio 1:10), profuse and friable calli were obtained at 25^oC in the darkness. The friable calli produced were transferred to fresh medium once every week for three weeks before transferring them to pre-regeneration medium containing ABA and NAA (replacing 2-4,D in the callus induction medium), and incubated for 9 days in the darkness at 25^oC.  Finally the creamy calli were transferred into regeneration medium containing high cytokinin (3 mg l^–1 BAP) with incubation at 28^oC and 12 h – photoperiod. Regeneration of plantlets was obtained between two to four weeks of transfer on the regeneration medium. The regeneration frequency (efficiency) of 53 and 42% were obtained for Suakoko 8 and FARO 55. Regenerated plants also produced viable seeds and hence fertile plants.

Key words: Embryogenic calli, regeneration, Suakoko 8, FARO 55, new rice for Africa (NERICA), Oryza sativa, Oryza glaberrima.