Abstract:

Application of cytoplasmic male sterility (CMS) materials makes an effective approach for utilization of heterosis, by which the seed pureness can be increased and the production cost can be reduced. A key problem for breeders is to identify unknown sterile cytoplasm and understand its characters. Using the combined methods of male fertility restoration testing, PCR of mtDNA and S1, S2 plasmid-like analysis, this study mainly dealt with classifying CMS-P selected from popcorn and finding the fertility diversity between CMS-P and others by pollen stain to understand the utilizing potential of CMS-P. The results indicated that CMS-P was classified to be the S-type CMS in maize. The PCR classifying method was quicker and exacter than others. And there was no difference between CMS-P and CMS-S in sequence of the special PCR fragment. The segregation proportion of pollen did not all accord with 1:1 by Chi-square test with pollen stain and CMS-P was much more fertile than CMS-Tangxu in restoring F₁. Pollen stain was diverse among the different nuclear backgrounds with same cytoplasm, the different cytoplasms and environments. The interaction between cytoplasm and nuclear minor gene maybe was the main factor that affects the fertility stability. We also found that HZ32 was a full restoring material with high restoring ability, and its rates of stained pollen were 96.4%, 94.2%, and 55.58% for CMS-T, CMS-C, and CMS-Tangxu, respectively. Ben7884 was a restoring line for S-type cytoplasm, but its restoring ability performed a fertility in 4–5 classes for C-type.

Key words: Maize, CMS-P, CMS, Cytoplasm classification, Stability