Abstract: The allotetraploid hybrids （AACC，2n = 4x = 38）derived from the hybridization between flowering Chinese cabbage（Brassica campestris L. ssp. chinensis var. utilis Tsen. et Lee）and broccoli （Brassica oleracea L. var. italica Planch） were as the female parent，through backcrossing with parent
flowering Chinese cabbage（AA），the allotriploid hybrids with AAC genomes were obtained. The allotriploid hybrids（AAC）were strong in growth and with the characters of both parents（flowering Chinese cabbage and broccoli）. Cytological identification revealed that the allotriploid hybrids had the
anticipative chromosomes （2n = 3x = 29）. The pollen viability and pollen number of one flower bud were lower than flowering Chinese cabbage and broccoli. The pollen-mother-cell’s meiotic chromosome behavior of allotriploid was complicated，such as the occurrence of chromosome lagging at metaphaseⅠ， anaphaseⅠ，metaphaseⅡ and anaphaseⅡ and the chromosome distribution at anaphaseⅠwas unbalanced， having 15/14，16/13 and so on. The complicate chromosome behavior in meiosis resulted the forming of gametes with different chromosome number.

Key words: flowering Chinese cabbage, broccoli, allotriploid, interspecific hybridization, meiosis