Regeneration of plants from rice caryopsis derived callus culture of Nigerian local cv. Suakoko 8 and a NERICA cv. FARO 55

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 25oC 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 25oC. Finally the creamy calli were transferred into regeneration medium containing high cytokinin (3 mg l–1 BAP) with incubation at 28oC 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.