Cytological investigation of microsporogenesis in a digenic recessive GMS line of Brassica napus

Meiosis and microspore development of the sterile and fertile plants of a digenic recessive genic male sterile(DRGMS) lines 479AB Brassica napus were investigated by the methods of cytological squashing and crossing section.Abnormity was observed at the stages of microspore mother cell(MMC),tetrads and uninucleate microspore,such as chromosomal bridge,chromosomal fragments and paraspores with unequal size microspores.Asynchrony of meiosis also took place within a single anther in sterile plants,i.e.microspore mother cells at pachytene I,metaphase and telophase II were all observed simultaneously in a single anther,whereas in fertile plants meiotic cells were at the same meiotic stage.In addition,microspores released from callose did not form the exine and their cytoplasm degraded gradually.Consequently,only debris was left in the distorted and shrank locules.