The Validation Of QTL Based Selection For OIL Content And Map Construction With QTL Analysls In Brassica Napus

In this study,firstly association between oil content traits and markers linked to QTLs was analysed as to81B. napus L. varieties (lines) from Europe, Canada, Australia and other Asian countries and different regions of China,by the14functional markers closely linked to7QTLs for oil content on the SG (Sollux X Gaoyou) genetic map,in order to detect if it is true that oil content variation was significantly associated with marker genotypes, and in order to explore the feasibility of marker-assisted selection and breeding based on QTL; Secondly, based on the SGE(SG14×Express617) segregating population a genetic map via272functional markers was constructed and compared with the SG genetic map,to lay the foundation for the integration between QTLs mapping or two genetic maps in the future; but al-so based on the new genetic map, QTL mapping of yield-related traits will provide new genetic information for genetic improvement of yield traits. The main results are as follows:1. Linked to the14markers,the Sollux high-oil alleles or the Gaoyou high-oil alleles were distributed in the81materials;it was verified that the oil-content QTLs were widespreaded in the rapeseeds (brassica napus L.) of natural population. The relevance was respectively at a significant or very significant level, between the six markers-Ra2E04(OilAl),ZAAS919å'ŒZAAS397(OilA5),ZAAS828å'ŒZAAS839(OilA7) and ZAAS441(OilC8-1linked to the4QTLs (OilAl, OilA5, OilA7and OilC8-1),and oily scale variation.2. Via random combination of the4markers significantly related to variation of the oil-bearing scale the comparative analysis about the oil content of marker genotypes of81varieties (lines),was developed to find that With the aggregate increase in the number of high-oil alleles oil content was significantly increased. The four markers would be used for MAS and combinable breeding.3. From the aggregation of the high-oil alleles linked to the four markers, European varieties better than the domestic varieties, the future, we would introduce foreign excellent Brassica napus L. germplasm resources, and more exchange of resources, promote genetic exchange of rapeseed germplasm resources, thus rich in Brassica napus L. resources to improve the gene pool.4. Genotypes of the DH lines were surved with the144polymorphic functional markers. A genetic linkage map was constructed using Mapmaker/Exp3.0.The linkage map consisted of18linkage groups,which included118markers and had a total length of1094.4cM with an average interval of9.27cM between adjacent loci. 5. Comparison between the linkage map of SGEand the map of SG showed that they had the same markers of79, the number accounted for66.9%of the total number of the markers in the SGElinkage map.Most of the same narkers on the same chcromosomes between the two maps were in the same order,but there were some markers on the four pairs of chcromosomes standing in different order. This illustrated well the gene rearrangements in the genome of Brassica napus quite common.6. Using composite interval mapping for the QTL of the traits related to yield were investigated.In total,12QTLs were detected for the four traits.Total2QTLs were detected for silique density with explaining15.84%of the phenotype variance.Five QTLs which have affected Silique lenth were detected with the QTLs explaining37.32%of the phenotype variance. Four QTLs which have affected number per siliqu were detected with the QTLs explaining33.39%of the phenotype variance.Only one QTL which have affected1000-Seed Weight were detected with the QTL explaining6.99%of the phenotype variance.