Study on Identification in Group of Cytoplasmic Male Sterile in Maize

Based on field experiment and microscopic examination of stained pollens, fertility restoration was detected using design Ⅱ in which 8 testers crossed with different fertility restoration genes with 14 isoplasmic and allokaryoplasmic cytoplasmic male sterile lines developed by backcrossing 3-6 recurrent male parent lines with cytoplasmic male sterile materials of group S, T and C for more than 8 generations. The results showed that ‘Zifeng1’ not only restored the isoplasmic and allokaryoplasmic sterile lines of group C backcrossed with ‘Mo17’, ‘Yu30’ and ‘Heer’, but also completely restored the isoplasmic and allokaryoplasmic cytoplasmic male sterile lines of group T backcrossed with ‘Mo17’, ‘HZS’,‘1792’,‘292’and ‘Yu30’. Therefore, it was limited by nuclear background to use ‘Zifeng1’ as a tester for identification of cytoplasmic male sterile. RFLP of mitochondrial DNA of 6 isokaryoplasmic and alloplasmic cytoplasmic male sterile lines were analysed with restriction endonuclease BamHⅠand HindⅢ and mitochondrial cDNA probe pBcmH3 and CoxⅡ.The same RFLPs were found within sterile Cytoplasm of group C, including ‘C’, ‘Chuan G’, ‘Lei 2’ and ‘Lei 3’, and the different RFLPs were distinguished apparently among sterile cytoplasm of group S, C, T and the normal cytoplasm. This result suggested that the RFLP markers tightly linked to sterile mitochondrial genes of different groups can be applied to identification of cytoplasmic male sterility.