Abstract: 45 lily cultivars imported from the Netherlands，including 21 Asiatic lilies，three Longiflorum lilies，seven Oriental lilies，eight LA hybrid cultivars，two LO hybrid cultivars and four OT hybrids cultivars，were analyzed using conventional chromosome preparation in this paper. Among the 21Asiatic cultivars，12 of them（‘Eleganza’，‘Monte Negro’，‘Renoir’，‘Black Bird’，‘Butter Pixie’，‘Orange Matrix’，‘Petit Brigitte’，‘Pink Pixie’，‘Lollypop’，‘Red Latin’，‘Marrakech’，and ‘Pollyanna’）are diploid（2n = 2x = 24），five of them（‘Navona’，‘Orange Pixie’，‘Elodie’，‘Vermeer’and‘Lyon’）are triploid（2n = 3x = 36），the rest four（‘Brunello’，‘Tresor’，‘Val di Sole’and‘Detroit’）are tetraploid（2n = 4x = 48）. All the three Longiflorum lilies（‘White Heaven’，‘Gelria’and‘White Fox’）are diploid（2n = 2x = 24）. All seven Oriental lilies（‘Siberia’，‘Sorbonne’，‘Maru’，‘Dynamite’，‘Dordogne’，‘Montezuma’and‘Miss Lucy’）are also diploid（2n = 2x = 24）. The eight LA hybrids（‘Brindis’，‘Courier’，‘Pavia’，‘Advantage’，‘Mestre’，‘Mombasa’，‘Pirandello’and‘Serrada’）are all triploid（2n = 3x = 36）. Two LO hybrids（‘Triumphator’and‘White Triumph’）are also triploid（2n = 3x = 36）. Among the four OT hybrids，‘Yelloween’and‘Red Dutch’are diploid（2n = 2x = 24），while‘Conca D’Or’and‘Golden City’are triploid（2n = 3x = 36）. The results show that most of the lily cultivars from intra-section hybridization（i.e.，Asiatic，Oriental and Longiflorum lilies）are diploid except for five triploid and four tetraploid Asiatic lilies，by contrast，nearly all lily cultivars from inter-section hybridization（i.e.，LA，OT and LO）are triploid except for two diploid OT cultivars.

Key words: lily, cultivar, ploidy