利用单片段代换系定位水稻粒形QTL

 【目的】水稻谷粒形状（粒长、粒宽和长宽比）是衡量稻米外观品质的重要指标之一，为更好地开展粒形分子育种，对水稻粒形QTL进行分子定位。【方法】以单片段代换系（SSSL）为材料构建分离群体，利用微卫星标记对控制水稻谷粒长和谷粒宽的2个粒形QTL进行分子定位。【结果】粒宽QTL Gw-8被定位于第8染色体长臂末端微卫星标记RM502与RM447之间, 遗传距离均为0.3 cM。在此基础上构建了覆盖Gw-8的物理图谱，RM502与RM447位于同一克隆AP005529，两者之间的物理距离为55.0 kb。粒长QTL gl-3被定位于第3染色体着丝粒附近的微卫星标记RM6146和PSM377之间，遗传距离分别为1.5 cM和11.0 cM。【结论】利用单片段代换系能准确地定位水稻粒形QTL，这两个粒形QTL的定位为其克隆及稻米外观品质的分子育种奠定了基础。

Mapping of the QTLs for Grain Shape Using Single Segment Substitution Lines in Rice

【Objective】Grain shape (grain length, grain width and length-width ratio) is a main index of rice appearance quality. For molecular breeding in rice, two QTLs controlling grain shape were mapped.【Method】The mapping populations were developed from the single segment substitution lines (SSSLs) in indica background of Huajingxian 74 and the two QTLs of grain shape were mapped using SSR markers.【Results】The grain width QTL, Gw-8, was mapped on the long arm of chromosome 8 between RM502 and RM447 with genetic distance of 0.3 cM. RM502 and RM447 located on the same clone AP005529 and the physical distance between RM502 and RM447 was 55.0 kb. The grain length QTL, gl-3, was located near the centromeric region of rice chromosome 3 between RM6146 and PSM377 with genetic distance of 1.5 cM and 11.0 cM, respectively.【Conclusion】The QTLs for grain shape in rice can be mapped using SSSLs. Mapping of Gw-8 and gl-3 has laid a foundation for cloning of the QTLs and molecular breeding of appearance quality in rice.