水稻抽穗期主效QTL qHd8.1的精细定位

 从广陆矮4号/日本晴染色体片段代换系群体中筛选到1个株系C23011。该株系除第8染色体短臂上的一个片段来自广陆矮4号外，背景均与日本晴相同。该株系在自然长日照条件下比轮回亲本日本晴提早抽穗约14.1 d，但在短日照条件下，两者抽穗期无显著差异。利用BC4F2世代中筛选到的一个目标区段杂合但背景基本纯合的单株自交一代后得到的BC4F3分离群体进行遗传分析。在该群体中单株抽穗期呈不连续的双峰分布，迟抽穗和早抽穗单株比例符合3∶1的分离比，表明抽穗期受1 个主效QTL qHd8.1控制。利用BC4F3群体中共1628株早抽穗的单株将qHd8.1精细定位在BAC克隆AP005164上标记S8111和S849之间，物理距离约为59.94 kb，该区间共有7个预测基因。

Fine Mapping of a Major QTL qHd8.1 for Heading Date in Rice

C23011,containing a single introgressed segment of chromosome 8,was derived from the CSSL population with Nipponbare as the donor and Guanglu′ai 4 as the recurrent parent.In normal long-day conditions,its heading date was 14.1 d shorter than that of Nipponbare.Under short-day conditions,however,no obvious difference in heading date between C23011 and Nipponbare was observed.A segregation population derived from a BC4F2 individual with the heterozygous target segment was used for genetic analysis and gene mapping.The ratio of late heading plants to early heading plants showed a 3∶1 frequency distribution,suggesting that the heading date variation was controlled by a single major QTL,which was named qHd8.1.A physical map was constructed encompassing the qHd8.1 locus and the locus was delimited to a 59.94 kb interval between markers S8111 and S849 on BAC clone AP005164 using 1628 individuals with shorter heading date originated from the BC4F3 populations.There are seven predicted genes within this region.