本课题以科农9204×京411重组自交系群体检测到的控制粒重的多环境稳定主效QTL qTkw-2D为对象，利用660K SNP芯片构建了高密度遗传连锁图谱。应用粗山羊草2D染色体物理图谱和BAC序列信息，开发与qTkw-2D紧密连锁和共分离的分子标记，构建靶区段饱和遗传连锁图谱；结合NIL家系表型数据和靶区段次级作图大群体，实现靶基因精细作图。利用与靶基因紧密连锁和共分离的分子标记筛选科农9204基因组BAC文库，对阳性克隆进行测序、组装和注释，确定qTkw-2D候选基因。对靶基因NILs家系产量相关性状进行多环境表型鉴定，解析其对产量相关性状的影响。利用小麦微核心种质（MCC）、育成品种及科农9204衍生材料，研究qTkw-2D在MCC和现代品种的遗传多样性；通过候选基因关联分析明确靶基因优异单元型，开发其功能性标记用于分子育种。

qTkw-2D, a major stable QTL for common wheat (Triticum aestivum L.) thousand-kernel weight (TKW), has been confirmed in ten different environments using a recombinant inbred line (RIL) population derived from the cross between Kn9204 and J411. In this project, we proposed to do fine mapping, map-based cloning and haplotype analysis of qTkw-2D using forward genetics approach. Using the RIL and advanced backcrossing segregating populations, a high-density fine genetic linkage map of qTkw-2D will be constructed via Affymetrix wheat 660K SNP array and sequence analysis of the Aegilops tauschii chromosome 2D BAC physical map and reference sequences. The molecular markers cosegregated or tightly linked to qTkw-2D will be used to screen the Kenong9204 BAC library to construct a physical map of qTkw-2D in Kenong9204. The candidate gene of qTkw-2D will be speculated after sequence annotation. The effects of qTkw-2D on yield-related traits will be characterized by phenotyping the NILs in multi-environments. The haplotypes and allelic variation of qTkw-2D will be studied using Chinese wheat micro-core collections (MCC), cultivars, as well as the Kenong 9204-derived advanced lines. The elite alleles and excellent haplotypes of qTkw-2D will be clarified via candidate gene association mapping analysis. The functional molecular markers of the excellent haplotypes of qTkw-2D will be developed and used in wheat molecular breeding programs designed to improve wheat kernel weight.