Abstract: Rice baploid young panicles (0.5-4 cm length) were cut into fragments in 1 mm size and cultured on a N6 medium with addition of 2.4-D 1 mg/l at 26℃ for 15 days. The fragments were easy to be induced into calli. About 30% of calli transferred on a medium with addition of NAA 0.5+KT 2 mg/l differ- entiated into plantlets. About 30 clusters of green plantlets were obtained from the fragments of one panicle on average. Plantlets also regenerated directly, not through callus, from the fragments cultured on a N6 medium with addition of NAA 1 +KT 2 mg/l. The shoot buds were initiated from the epidermis cells and cortex cells adjacent to them at the region between.the sterile lemma and the fertile lemma of a spikelet on a fragment. About 12 clusters of plantlets were obtained from the fragments of one panicle by this way. In both cases, albino plantlets were less than 2% in regenerated plantlets. 98% of regenerated plants were haploids. However, treating the calli with the colchicine at 200 mg/l in 42% dimethyl sulphonate(DMSO) aqueous solution resulted in production of 50% fertile diploids in regenerated plants without decreasing the differentiation frequency of calii.

Key words: vitro, culture, rice, panicle