利用染色体片段代换系定位水稻主效抽穗期QTL

Mapping of a major QTL for heading date in rice using chromosome segment substitution lines

从日本晴/明恢63染色体片段代换系中筛选到1个抽穗期分离家系BC3F2,调查该家系327个单株,发现单株抽穗期呈明显双峰分布,晚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QTLqHd-3控制.利用极端集团混合法筛选到标记RM416在2个DNA混合池中有多态性,单因子方差分析证明了标记RM416和qHd-3连锁.在引物RM416附近20cM继续筛选多态性标记,对BC3F2群体进行基因型分析,构建局部连锁图.通过QTL分析,qHd-3被定位在IDL01—RM5995,与2个标记的遗传距离分别为5.3cM和1.5cM,它可以解释表型变异的62.9%.在同一区间内还检测到控制每穗颖花数微效QTLqSpp-3和分蘖数微效QTLqTn-3.

One BC3F2 line segregating with heading date was found from chromosome segment substitution lines （CSSLs） derived from the cross, Nippanbare/Minghui63. The frequency distribution of heading date showed bimodality in the segregation population of 327 plants and the ratio of late heading individuals to early heading individuals showed 3 ： 1, suggesting that heading date was controlled by a single major QTL qHd-3. The strategy of bulked segregant analysis （BSA） was used to quickly locate the QTL. SSR marker. RM416. was identified with polymorphism between two DNA bulks consisting of early and late heading plants, respectively. One-way ANOVA was performed to confirm the linkage between RM416 and qHd-3, qHd-3 was located to a region between InDel marker IDL01 and SSR marker RM5995 using interval mapping method, qHd-3 was 5.3 cM and 1.5 cM from loci IDL01 and RM5995 respectively, accounting for 62.9% ofphenotypic variance. Besides, two minor QTLs, qSpp-3 and qTn-3, controlling spikelets per panicle and tillering number respectively were detected in the same region with qHd-3. The present results have established a basis for the molecular marker assisted breeding fine mapping and gene cloning of qHd-3.