Abstract: The aim of this study was to establish an efficient system of plantlet regeneration and seedling production for Hippeastrum. We focused on embryogenic calli induction from immature pedicel explants and plantlet regeneration. The effects of plant growth regulator concentration，the developmental period of the explant，and explant size were evaluated. The highest induction rate of embryogenic calli（85.3%）was achieved by culturing 1 mm thick slices of immature pedicel explants on Murashige and Skoog（MS）medium supplemented with 0.5 mg ? L-1 N-phenyl-N’-1,2,3-thiadiazol-5-ylurea（TDZ）and 2.0 mg ? L-1 2,4-dichlorophenoxyacetic acid（2,4-D）for 8 weeks. Embryogenic calli were subcultured on the same medium and were subcultured once a month. Under these conditions，the proliferation rate of embryogenic calli was 10.6-fold per month. The plant regeneration rate of embryogenic calli reached 98.0%，and an average of 12.3 plantlets formed from each embryonic callus on MS medium without any growth regulators. After subculturing 36 times（3 years），there were no significant changes in embryogenic calli proliferation and plant regeneration efficiency. The survival percentage of these seedlings hardened in the greenhouse was 97.5%. After transplanting into the field，no obvious phenotypic variations were observed among the regenerated plants. Inter-simple sequence repeat（ISSR）marker analysis supported the absence of DNA-level variations among the regenerated plants.

Key words: Hippeastrum, embryogenic calli, ISSR, proliferation, regeneration