Abstract

The objective of the present study was to develop an effective protocol for optimum callus induction, duration of culture and size of explants of primordial panicle of inter-genomic hybrid of Oryza sativa/ Oryza brachyantha. It was observed that, primordial panicle at very young stage (0.5 to 1.5 cm) takes hardly 5 to 7 days for callus initiation. The two basic media tested, the Murashige and Skoog (MS) medium and Chu’s N₆ medium supplemented with 2-4-D, NAA and kinetin (2 mg L^-1 2 mg L^-1 and 1 mg L^-1) was better for callus growth and proliferation. In this medium, callus was sub-cultured continuously for 12 passages (12 months) without loss of totipotency. Plantlet regeneration in MS medium was examined using two cytokinins (KIN and BA) along with one auxin NAA at various concentrations and combinations. Tests indicated that, good plant regeneration could be best effected without BA, but with 1.5 to 2.0 mg L^-1 of KIN at fixed level of NAA (at 0.5 mg L^-1).

Key words: Somaclonal, callus, subculture, wide cross, MS medium, N₆ medium.