本项目申请旨在前期研究积累基础上，针对油菜SG群体C8连锁群上一个在多环境中稳定表达，效应值最大和LOD值最显著的控制粒重QTL（qSWC8），通过标记跟踪构建qSWC8-近等基因系，精细定位该QTL，利用拟南芥和芸苔属基因组信息在精细定位基础上筛选可能对qSWC8起重要作用的候选基因。研究内容包括在qSWC8区域发展位置特异性标记，增加标记密度；2) 通过回交自交结合前景和背景选择构建BC4F2, BC3F3 和 BC5F1等近等基因系群体； 3）应用BC3F3和BC4F2世代近等基因系群体精细定位qSWC8在<300kb的基因组区域内；4) 利用多环境多重复田间表型鉴定结果进一步确认QTL遗传效应，明确qSWC8与含油量以及角果粒数之间是否有遗传相关或连锁。为挖掘高油、大粒/多粒的高产优良基因资源，为下一步的图位克隆积累材料和奠定研究基础。

The applied proposal is on the basis of our long term research accumulation for QTL analysis in Brassica napus. The aim of present study is to fine mapping a major QTL, which showed most significant and stably expressed additive effect for 1000-seeds weight on linkage group C8 of SG-DH population (qSWC8). The research activities will include 1) to increase marker density in qSWC8 region by developing locus specific markers focus on qSWC8 using homozygous sequence resources from Brassica rapa A9 or Brassica oleracea C8; 2) to develop BC4F2, BC3F3 and BC5F1 populations through marker assistant foreground and background selection; 3)to narrow the qSWC8 to <300kb physical region by substitution mapping using BC3F3 and BC4F2 generations; 4) to estimate the genetic contribution of qSWC8 to seed weight and confirm the genetic relationships among seeds weight, seeds per silique and oil content on this locus by multiply field test ; The expected results will provide a good base for further map based gene cloning. The qSWC8 linked markers would be a useful tool for breeding purposes.