Studies On Cytoplasmic Male Sterility WJS01A In Brassica Juncea As Well As Its Derivatives

Rapeseed is the major source of ediable oil and vegetalbe protein. Heterosis is the main way to get high quality and high yield, and cytoplasmic male sterility is one of the important ways for utilization of heterosis. WJSOIA is a novel CMS found in the field by Prof. Wu Jiangsheng and its sterility is stable and not affected by environment. We studied WJSOIA and its derivatives at the morpholological, celluar genetic and molecular biological levels, meanwhile, WJSOIA was confirmed to be a new type of cytoplasmic male sterility by testcrossing with lots of varieties. The main results are as follows:1. Compared to B.juncea, WJSOIA and its derivatives were not influenced during seedling period in four environments in two years. The pistil of WJSOIA CMS was normal, while its stigma was higher than anther and its four nectaries was green and plumpness. The anthers had no pollen in CMS plants and their colour were white. Interestingly, the morphological of floral organ of its derivatives are different from WJSO1A CMS.2. WJSOIA CMS was testcrossed with the restorers and maintainers of Pol CMS, Ogu CMS and Kos CMS, respectively, and their F1fertility was investigated. The results indicated that these restorers could not restore the fertility of WJSOIA, suggesting that WJS01A CMS could not been restored by restorer lines from Pol CMS, Ogu CMS and Kos CMS systemes. To screen for restorers,300cultivars of different origin were testcrossed with WJSOIA. However, no restorer lines were identified.3. Cytological observation of WJSOIA anther development indicated that it has no clinandrium with paraffin wax slice method. Paraffin section results confirmed the microspore abortion characteristics of squashing results. The stamen primordium deviated from the normal polarization so that it couldn’t produce pollen through a process of differentiation. The abortion of microspores might occur before to behind of the sporogonia.4. Specific PCR, multiplex PCR and mitochondrial RFLP analysis of mitochondial genes were done to compare five different CMS types and the derivatives of WJSOIA CMS. The results indicated that specific PCR can be used to identify known CMS and WJSOIA CMS is different from Pol, Ogu and Kos by multiplex PCR, while there is no difference between it and B.juncea. Out of eight mitochondrial probe/enzyme combinations, all the probe/enzyme combinations exhibited slight variations among WJSOIA CMS and its derivatives. Therefore, we may conclude that although WJS01A CMS might be affected by several conditions during genetic processes, expression and regulation of the sterility gene remain activation. However, six combinations exhibited polymorphism among them which confirmed that WJSOIA CMS is a new type of sterile cytoplasm.