| Rapeseed is one of the major oil crop in China,and its heterosis is significant.The CHA is a major approach for heterosis utilization.There are many advantages of CHA in producing hybrids,such as more flexible in parental choice,short cycle and without adverse cytoplasmic effects.In this thesis,in order to breed new rapeseed varieties with high quality,high yield,multi-resistance and multi-function faster and better with chemical male sterility method and to produce high-purity hybrids,the characteristics of six new germplasm materials were studied and five new rapeseed varieties(combinations)in different regions were prepared according to the different characteristics of six new germplasm materials.Six parental lines of Brassica napus L.were tested for effects of sterile induced by using compound chemical male sterility(EN2)with independent intellectual property rights.The effects of sterile induced was tested at different concentrations.Through field investigation,cytological observation and determination of acetolactate synthase(ALS)activity,the optimum chemical male sterility concentration of six parental lines were studied.The effects of EN2 on Agronomic traits,flower organ morphology,pollen viability,fertility and ALS activity of Brassica napus L.were also studied.The results show that:1.Six new germplasm materials have obvious differences: S1 has strong lodging resistance,disease resistance,pod cracking resistance and wide adaptability.Shanxi Oil 1203,a new cultivar,meets the registration standards of three regions of the country.It is especially suitable for mechanized harvesting and planting in the lower reaches of the Yangtze River,Yellow River,Huaihe River and Southern Shanxi Province.S6 has high oil,high yield and disease resistance.The new variety Shanxi Oil 1309 has high oil and high yield,which meets the registration standards of three regions of the country and is suitable for planting in the middle reaches of the Yangtze River,Yellow River,Huaihe River and Southern Shanxi Province.The combinations of S2,S3,S4,and S5 are also outstanding.2.The sensitivity of six materials to EN2 is different,which can be divided into three types: blunt type,relative sensitive type and sensitive type.Among them,S2 and S3 belong to the sensitive type.And the treatment of 0.5μg/mL EN2 at uninucleic stage and initial flowering of S2 and S3 had the best efficacy with over 95% completely sterile plants.S1 and S5 belong to the relative sensitive type.And the treatment of 0.9μg/mL EN2 at uninucleic stage and initial flowering of S1 and S5 had the best efficacy with over 95% completely sterile plants.S4 and S6 belong to the blunt type.And the treatment of 1.3μg/mL EN2 at uninucleic stage,0.9μg/mL EN2 at initial flowering of S4 and S6 had the best efficacy with over 95% completely sterile plants.3.At uninucleic stage of Brassica napus L.,the treatment of EN2 on the stems and leaves had the best efficacy with over 95% completely sterile,but had little effect on the fertility and the agrinomic traits of Brassica napus L.The anther was shriveled,dwindled to be acerate shape and fade,and the length of filament was shortened.There was no pollen or only shrunken,malformed and aborted pollen.4.The number of flowers with trace pollen of CMS 209 A,203A and Xianhuang A were reduced in visibly with EN2 at the uninucleate stage,and the sterile degree was raised,the inhibitory action to the trace pollen was chearly.The sensibility of different CMS to EN2 was different,the optimum concentration to three CMS 209 A,203A and Xianhuang A was 0.5μg/mL、0.5μg/mL、0.7μg/mL.5.The activity of ALS in three different stages and two parts decreases in late bud stage and reaches the lowest level and stabilizes at flowering period.The ALS activity of flower bud decreases more than that of leaf,indicating that ALS activity is strongly inhibited in flower bud,and is most inhibited at full flowering period.The ALS activity of S4 is most inhibited and that of S3 was least inhibited. |
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