Abstract: WBMs is a cytoplasmic male sterile line developed by Huazhong Agricultural University. The microspore genesis of WBMs was observed by optical and electron microscope. The results indicated that the microspores of WBMs could normally develop before the middle stage of microspore, but some of microspores began degradation in the late stage, and others could normally develop until the bi-nuclear pollen stage, sequentially, the pollen grain collapse suddenly, as a result, shrunken pollens were formed. The process of microspore abortion of WBMs was similar to Tangxu CMS of S group which pollen abortion is happened in late developing stage and the normally somatic activity such as tapetal cell. The sterility of WBMs was typical gametophyte sterility. According to its cytological characters, cytoplasm of WBMs can be preliminarily classified into S group of maize CMS.

Key words: Maize (Zea mays L.), Cytoplasmic male sterile, WBMs, Microspore abortion, Electron microscope