Cytological studies in Carassius auratus var pengze

It was observed that fertilization cytology of Carassius auratus vat pengze (♀)×Carassius auratus var pengze (♂). It was observed that after being inseminated, a sperm entered egg through micropyle and a polar body was extruded. But after a sperm entered the egg, spermatozoon nucleus beside female pronucleus was condensed and cannot fuse with female pronucleus. The result shows that Carassius auratus var pengze is a gynogenetic reproductive species. There were no pairs of homologous chromosome in meiosis Ⅰ metaphase of spermatocyte of Carassius auratus var pengze. It shows the unusual meiosis Ⅰ during spermatogenesis. The ratio of DNA relative content of tail fin cell to sperm of Carassius auratus vat pengze is 2.218: 1, and it reveals that DNA relative content of sperm is half of somatic cell. During spermatogenesis, meiosis Ⅰ is abnormal. This paper preliminarily analyzed the mode of the stability of chromosome ploidy of Carassius auratus vat pengze and the different mechanism of ogenesis and spermatogenesis in order to better understand the reproductive modes and formation mechanism of triploid of Carassius auratus var pengze.