Dissection Of QTL Cluster For Seed Oil Content And Analysis Of Linkage Drag In A8 Linkage Group Of Brassica Napus L.

As a super consumer of plant oil, our country's level of dependency on import comes to 61%. Seed oil increment of Brassica napus, one of the most important sources of plant oil, will not only secure, but also improve its supply. At the same time, rapeseed oil earns popularity with its character of high oleic acid content and low linolenic acid content. However, primarily from forage rapeseed, genes which are negative to seed oil accumulation together with their tightly linked "lower erucic aicd" gene, were transferred into elite cultivars during the process of "lower erucic acid". Therefore, detailed understanding of genetic mechanism of seed oil accumulation of rapeseed and breaking linkage drag between seed oil content and eruci acid content will theoretically serve as guidelines for breeding higher seed oil content cultivars.We detected seed oil content and erucic acid content QTLs in A8 of TN DH mapping population in 12 and 10 environments, respectively. Evenmore, their confidence intervals overlap. In order to separate this QTL cluster, break linkage drag between seed oil content and erucic acid content and quantify their relationship in A8 linkage group, we have densified this region with BAC-based SSR markers through comparative genomics and constructed NILs through consecutive backcrossing by Ningyou7. Results stated as below:14 BAC-based SSR markers, developed from 49 sequenced BAC of Brassica rapa, were mapped in this QTL region through comparative genomics.Result of redetecting seed oil and erucic acid content QTL of A8 linkage group demonstrated that number, location, and effect of QTLs differed significantly from those before. Seed oil cotent QTLs of this region were integrated into 7 consensus QTLs after meta-analysis.NILs corresponding to 4 consensus seed oil content QTLs were selected from BC4F4, and their genotypic effects were analyzed as well. Two segregating populations,8L097-8 and 8L099-2, were planted to analyze the relationship between seed oil content and erucic acid content in linkage group A8.In sum, utilization of sequenced DNA information through comparative genomics is an efficient way to densifying QTL region with molecular markers. These markers will not only be helpful in selecting NILs, but also serve as important tools for breaking linkage drag between seed oil content and erucic acid content in A8 during future rapeseed breeding programs. Selected NILs have been successfully used to separate seed oil content QTL cluster and quantify the relationship between seed oil content and eruci acid content in A8.