Studies On The Genetic Characteristics And Utilization Of Cytoplasmic Male Sterile Lines Of Zheng58

Male sterility is a crucial approach for heterosis utilization. Maize(Zea mays L.) is the first crop applied male sterility for hybrid seed production. Use of male sterile lines of a hybrid system can be removed from artificial emasculation, lower labor costs and improved seed purity. Therefore, exploring the genetic basis, cytoplasmic type and utilization potential of cytoplasmic male sterility, has become an important research field of genetic breeding of maize. Usinginbred line Zheng58 and two cytoplasmic male sterile lines of Zheng58 as experimental materials, fertility stability were observed and the cytoplasmic types were discriminated. Meanwhile microspore genesis were observed,agronomic traits, biochemical and photosynthetic characteristics were analyzed.Finally, the utilization potentials were studied through the comparison of hybrid agronomic traits and yield related traits. The main results were as follows:1.The male sterility characteristics of two cytoplasmic male sterile lines, Zheng58cms-M084 and Zheng58cms-Q1261,were stable in different locations and years, no anthers exposed on tassel and pollen aborted completely.2. The ear height of Zheng58cms-M084 and Zheng58cms-Q1261 were significantly shorter than that of Zheng58 andgrain protein content of Zheng58cms-M084 and Zheng58 were significantly lower than that of Zheng58cms-Q1261.The other traits such as plant traits, panicle traits, grain quality traits were no significant difference among two sterile lines and Zheng58.3. Using the method of cytoplasmic type classification based on PCR amplification with specifically primers, the specific bands amplified by S type specific primers were obtained, while C and T primers did not amplify specific bands. Zheng58cms-M084 and Zheng58cms-Q1261 were classified into Stype of CMS. The F1, F2 of Zheng58cms-M084×AP72, Zheng58cms-Q1261×AP72 were fertile, and(Zheng58cms-M084×AP72)×Zheng58,(Zheng58cms-Q1261×AP72)×Zheng58 showed 1:1 fertility segregation.Therefore, they were gametophyte sterility.4. The microspores of Zheng58cms-M084, Zheng58cms-Q1261 could normally develop before the middle microspore stage, but some of microspores began degradation at late microspore stage, and others could normally develop until the bi-nuclear stage, the pollen grain collapsed suddenly, and tapetal cells could maintain the normally somatic activity.5. Soluble sugar content in the leaves of Zheng58 was significantly lower than that of two sterile lines at pollen shedding stage, while the content of soluble sugar in the anthers of Zheng58 was significantly higher than that of two sterile lines. Free proline content in the leaves of Zheng58 was significantly lower than that of Zheng58cms-Q1261 only at the later stage of tassel florets development, while the content of free proline in the anthers of Zheng58 was significantly higher than that of two sterile lines at the early stage of tassel florets development and pollen shedding stage. MDA content in the leaves of Zheng58 was significant difference with two sterile lines during different developmental stages except the later stage of tassel florets development and tasseling stage, while the content of MDA in the anthers of Zheng58 was not significant difference with two sterile lines at the early stage of tassel florets development and pollen shedding stage.6. Plant traits, ear traits and yield, grain quality traits of Zheng58 hybrid were no significant difference with two sterile lines except that Zheng58cms-M084 hybrid plant height, ear height were significantly lower than that of Zheng58 hybrid, and Zheng58 cms-Q1261 hybrid kernel lysine content was significantly lower than that of Zheng58 hybrid.