Discovery And Genetic Study Of New CMS In Transform Regeneration Maize

In this text, we used transgenic Bt maize by Agrobacterium as the main research materials. On one hand, it measured whether the interest gene continued heredity in the transform regeneration. On the other hand, we obtained a great deal of phenotype variation from the T₂ generation plants. The difference of 7 agronomic characters between separate lines of interest gene and CK were analyzed. Stable male sterile lines were obtained after those materials were pollinated by acceptor inbred lines of "18 red" . The main results showed as follow:1. The interest gene separated in T₂ generation plants was verified by molecular detection. The proportion of the positive plants was lower than 3:1. It did not accord with Mendel' s law.2. A large amount of sterile plants appeared in every lines of T₂ generation. Through compared with CK and non-interest gene lines, we drew the conclusion that the male sterile variation arose by somaclone variation.3. Compared the difference of 7 agronomic characters among separate lines of interest gene, non-interest gene lines and CK, the results showed that inserted interest gene had smaller influence on the variation of plant height, ear height, ear length, rows/ear, grains/row, grains/ear and seed setting. We speculated that culture worked on somaclone variation.4. Sterile plants crossed by acceptor inbred lines of "18 red" and breeding plants of the homologous ear row. It was proved that sterile variation should be steady heredity through observation of several generations. We found relative maintainers and restorers when all sterile ear crossed by many normal inbred lines. So we concluded sterile variation attributed to cytoplasmic male sterility.5. Two sterile ear rows backcrossed by the relative maintainers. The sterile stability was observed in 2 locations, for 2 years and 3 generations. The results indicated the sterile stability was affected by climatic conditionsin Sichuan, and it was very steady in Yunnan.6. The results were consistent when two all sterile ear rows crossed by "Zifengl" and "Hui313" . But it was not consistent when it crossed by "48-2" . This proved that culture had different influence on cytoplasm andnucleolus of the two materials, even if using the same lines crossed with the same receptor material, we obtained different results.7. Using male fertility restoration testing could classify the two sterile materials into C type. But fertility separate proportion of F2 of restoring type (sterile linesX48²) did not accorded with C type' s. Therefore, it was limited by nuclear background to use "Zifengl" as a tester for identifica -tion of cytoplasmic male sterility. We can combine other methods such as inoculated identification with T—race of Helminthosporium maydis, RFLP mtDNA analysis and so on, to classify cytoplasm type exactly.