The novel male sterility line 12-14A of Wucai ( Brassica campestris ) was generated by backcrossing. In this study, morphological,molecular, and cytological analyses were performed to characterize this line. The phenotypes of fl ower organsof 12-14A were diff erent from those of its maintainer line 12-14B, as the fl owers of 12-14A were completely infertile. Molecular analysis confi rmed that the male sterility line 12-14A was classifi ed as the ogu CMS type. An analysis of antherdevelopment in the CMS line demonstrated that two types of abortion occur simultaneously: pollen mother cell abortionand tetrad-to-mononuclear microspore abortion. In addition, the mature anthers of 12-14A showed typical abortive features,such as appearing dry, shrunken, and scaly. A heterosis test of hybrids from CMS 12-14A and four inbred lines was carriedout, and the F 1 hybrids exhibited clear heterosis in plant weight, as well as in the protein, soluble sugar, and vitamin C content,suggesting high yields and high quality potential. These results indicate that this novel CMS line may have powerfulpotential in Wucai hybrid breeding.