新型玉米Y型雄性不育系的特性与遗传

Character and Inheritance of A New-type Cytoplasmic Male-sterile Line in Maize (Zea Mays)

利用恢复系的细胞质创造不育系是选育新型不育系的有效途径。采用此法先后选育出Y_Ⅰ型和Y_Ⅱ型玉米不育系。据数年来对Y型不育系的抗病性、恢保关系,光学细胞学、电镜超微结构、生化特性、遗传特性等方面较为系统的研究,初步确定Y型不育系是有别于C群、T群和S群的新型不育系。其归群尚待进一步研究。Y型不育系育性遗传稳定、三系配套。恢复系较多且抗病性强,是一份宝贵的种质资源,有较大的利用价值。

It is a useful approach to create new types of male-sterile lines by means of combing sterile cytoplasms of restorer lines with maintainer nuclear backgrounds. In this way, we have bred two types of maize male-sterile lines, nominated Y_Ⅰand Y_Ⅱ types respectively. The researches on their resistance against HmT. ( Helminthosporium maydis race T), fertility restoration patterns, light microscopy, electron microscopic ultrastructure, biochemical character and hereditary traits have been conducted systematically for several years. The results indicated: (1) The induced assay was done with Y-type male-sterile lines of the resistance against H. maydis, the disease index of Y-type was 10-20% which was similar to that of disease resistant inbred line Su-80-1 and C group male-sterile line B_37. (2) The chromosome heavily lagged in division at anaphase I in C group male-sterile line which showed an asynchronous chromosome division. such a situation existed both at anaphase Ⅰ and Ⅱ in T group male-sterile line. And the development of microspores in Y-type male-sterile line was slightly abnormal. (3) It is known that there existed a distinct difference in the pollen abortion between C group and Y-type male-sterile lines, the pollen abortion in C group male-sterile line occurred at the early mononucleate stage after the division of tetrad, while in Y-type male sterile line, at the late mononucleate stage. (4) Under the electron microscope, it was observed that the structure of nuclei in Y-type male-sterile line cells seems a little damaged, the chromatin was concentrated into a densestaining mass. (5) The analyses of esterase isozyme and isoperoxidase isozymes were done by ployaerylamide gel electrophoresis with male-sterile line and their respective maintainer lines, we found that C. T. S group male-sterile line were different from Y-type in zymogram patterns. (6) Besides, in hereditary traits, we have studied and discussed the following content: Identification of the number of restorer genes, the change of restoring power of transforming restorer line at various backcross pedigrees and the influence of cyto-plasms, parental nuclear backgrounds and their interactions on restoring power.