Abstract: Microsporogenesis of two cytoplasmic male sterile (CMS) lines 66A and 61A , one genic male sterile ( GMS) line 76A and their maintainers was investigated cytologically by using plastic semi2thin sections with light microscopy. The complete abortion of 76A occurred at the stage of meiosis , the pollen mother cells could not develop to form tetrads due to the abnormal meiosis meanwhile the tapetum cells degenerated prematurely. CMS 61A line formed abnormal tetrad. The callose wall did not degenerate and no microspores were released from the tetrad. At the same time , an abnormal morphology of the tapetum cells was observed , which showed either hypertrophy or a
formation of periplasmdium. The inhibition of mosporogenesis of CMS 66A occurred at the uninucleate stage when the microspore failed to continue gametogenesis and abnormal vacuolation and rudimental exine were observed. The tapetum cells were abnormal with hypertrophy or forming periplasmdium.

Key words: Brassica rapa L. ssp. pekinensis, Male-sterile, Microsporogenesis