An efficient somatic embryogenesis system was developed to regenerate plantlets from hypocotyls of upland cotton cultivars Lumian 6(Gossypium hirsutum L.).The cultivar Lumian 6 was cultivated in North China,the same cotton planting region as YZ1,an easy-going genotype somatic embryogenesis.Calli were produced on the medium with twelve different hormone regimes,the hormone regimes 1.0 mg/L IBA only or 0.1 mg/L 2,4-D together with 0.2 mg/L KT were the best for inducing calli from Lumian 6.After about 4 weeks,the peripheral cultures were separated from explants and transferred to fresh MS medium with half auxin and doubled KNO3.After two to three subcultures (30 days intervals),friable,yellow-green or grey-green embryogenic cultures and somatic embryos was effectively observed in ECM media with low concentration of auxin (0.01 mg/L 2,4-D and 0.1 mg/L KT or 0.1 mg/L IBA only).After being transferred to the media for differentiation and embryo-germination,somatic embryos were produced and further developed.The two varieties can regenerate plantlets in 6-8 months using the protocols mentioned above.Histological observation demonstrated that the majority of embryogenic calli originated in a familiar way in the two genotypes and proved that the cells from primary cambium cells were the original cells for forming cotton embryogenic calli.