Studies On Ecotypical Male Sterile Line 373S And A Chlorsis Mutant In Oilseed Rape

In the present , cytoplasmic male sterility, geneic male sterility and chemical hybridization agent are the main approachs for utilization of heterosis in rapeseed. Two line method using ecotypical male sterile to produce hybrid seeds is becoming a new approach to utilize the heterosis in rapeseed, and the discovery and study of new male sterile accessions is always its most important basic works. Our research group discovered a chimerically male sterile rapeseed (Brassica napus L.) in the open-pollinated family from a spontaneous male sterile population and successfully developed an environment-sensitive male-sterile line 373S. To reveal its genetic mechanism and utilize this accession in the breeding programme, 373S was characterized by temperature treatment, cytological observation, classical genetic investigation and isoenzyme analysis. The results shows that according to the results of temperature treatment in the growing chamber and the field investigation, 373S is a low temperature sterile type. The switch temperature and the sensitive period of buds were identified primaryly; anther abortion of 373S initiated at mononuclear cell phase. The main feature was no big vacuole forming. This might disturb the first mitosis of mononuclear cell, block the formation of vegetative nucleus and generative nucleus, and lead to abortion of mononuclear cell; 373S was controlled by two pairs of recessive nuclear gene; There exsit some differences between 373S sterile anther and the wild type in zymogram of perioxidase and esterase. Compared to the wild type, zymogram of perioxidase and esterase of 373S sterile anther occured some more bands.In order to reveal the mechanism of chlorsis mutant and provid alternative genetic mark, a chlorisis mutant in Brassica juncea L. was primarily characterized by field investigation, determination of chlorophyll content and analysis of zymogram. Compared to the wild type L638-g, the width of cotyledon, plant height, the number of the primary branches and yield per plant of the chlorisis mutant reduced. The mutant bloom one day later, but mature one day early, which indicating that the chlorisis mutant has a large influence on plant development. The content of chlorophyll a, chlorophyll b, and carotenoid in the leaves of the mutant plants decreased, especially the content of chlorophyll b decreased sharply. The mutation may have influence on the transform from chlorophyll a to chlorophyll b. No obvious difference of the zymogram of peroxidase and esterase isozyme was observed between the mutant and the wild type. In summary, the chlorisis mutant in Brassica juncea L. probably belongs to one of the total chlorophyll deficient mutants.