利用染色体片段置换系定位水稻落粒性主效QTL

水稻落粒性是与其生产密切相关的重要性状之一。以7个染色体片段置换系为材料, 采用重叠群代换作图法对控制落粒性的2个主效QTL进行定位。结果表明, 104个SSR标记在亲本间具有多态性, 多态率为68.0%; 4个置换系的落粒性与亲本日本晴的落粒性相似, 表现难落粒。3个置换系与亲本93-11的落粒性相似, 表现易落粒; 7个染色体片段置换系在第1和第6染色体上检出7个置换片段, 其长度分别为23.6、16.5、 6.6、 9.9、 10.4、 20.2和7.1 cM; qSH-1-1被定位在第1染色体RM472－RM1387之间, 遗传距离约为6.6 cM。qSH-6-1为新发现的落粒性主效QTL, 被定位在第6染色体RM6782－RM3430之间,遗传距离约为4.2 cM。利用染色体片段置换系能准确地定位水稻落粒性QTL, qSH-1-1与qSH-6-1的鉴定和初步定位为其进一步的精细定位、图位克隆及分子标记辅助选择奠定了基础。

Substitution Mapping of Quantitative Trait Loci for Seed Shattering in Chromosome Segment Substitution Lines of Rice (Oryza sativa L.)

Seed shattering plays an important role in rice breeding. Using an indica variety 93-11, a japonica variety Nipponbare and seven chromosome segment substitution lines (CSSLs ) with a genetic background of 93-11 introgressed from Nipponbare as the materials, we investigated seed shattering with 153 simple sequence repeat (SSR) markers on rice chromosomes , the introgressed segment and the quantitative trait loci (QTL) for seed shattering. Among the SSR markers , 104 displayed polymorphism bands between two parents, and the rate of polymorphism was 68.0%; among the CSSLs, the seed shattering of four was the same as for Nipponbare, and that of the other three was the same as for 93-11. Four CSSLs had four introgressed segments on rice chromosome 1 and three had three introgressed segments on rice chromosome 6. The genetic distance for the seven introgressed segments was 23.6, 16.5, 6.6, 9.9, 10.4, 20.2 and 7.1 cM, respectively; qSH-1-1 was mapped in the region of RM472-RM1387, with 6.6 cM genetic distance on rice chromosome 1. qSH-6-1 was mapped in the region of RM6782-RM3430, with 4.2 cM genetic distance on rice chromosome 6. The QTL for seed shattering in rice can be mapped primarily by use of CSSLs. Mapping the QTL has laid a foundation for fine mapping and cloning the QTL and molecular marker-assisted selection of appearance quality in rice.