Abstract: Chromosome segment identification of rice chromosome segment substitution line Z745 was conducted, and QTL mapping of panicle traits of secondary F2 population which was constructed by crossing with Nipponbare as the background parent and Z745 as the donor parent was studied,so as to find new QTL for panicle traits.The results showed that Z745 contained 17 substitution fragments,which were distributed on chromosomes 1,3—8,10 and 12.The replacement length was 26.1 Mb,and the average replacement length was 1.54 Mb.The panicle length,primary branch number,secondary branch number and grain number per panicle of Z745 were all significantly higher than those of Nipponbare.Twenty one QTLs of panicle traits were identified,which were distributed on nine substitutional segments,located on chromosomes 1,3—5,7—8,10 and 12.Among them,4 QTLs for panicle length were on chromosomes 1,4 and 7;4 QTLs for primary branch number were on chromosomes 1,5,7 and 8;6 QTLs for secondary branch number were on chromosomes 1,7,10 and 12;7 QTLs for grain number per panicle were on chromosomes1,3,7,8 and 10 respectively.The panicle length QTLs(qPL7-1,qPL7-2),secondary branch number QTL(qNSB7-1)and grain number per panicle QTL(qSPP1-1) located in this study had been reported,while the remaining ear trait QTLs had not been reported yet.

Key words: QTL mapping, Panicle traits, Chromosome segment substitution line, Rice

摘要： 对水稻染色体片段代换系Z745进行染色体代换片段鉴定，并用以日本晴为背景亲本、水稻染色体片段代换系Z745为供体亲本杂交构建的次级F2群体定位水稻穗部性状QTL，以期发现新的穗部性状QTL。结果发现，Z745共含有17个代换片段，分布于第1、3—8、10和12染色体，代换片段总长度为26.1 Mb，平均代换长度为1.54 Mb；Z745的穗长、一次枝梗数、二次枝梗数和穗粒数均极显著高于日本晴；鉴定出21个穗部性状QTL，分布于其中9个代换片段上，位于第1、3—5、7—8、10和12共8条染色体上，其中，穗长QTL 4个(1、4和7染色体) 、一次枝梗数QTL 4个(1、5、7和8染色体)、二次枝梗数QTL 6个(1、7、10和12染色体)、穗粒数QTL 7个(1、3、7、8、10染色体)。定位到的穗长QTL qPL7-1、qPL7-2)、二次枝梗数QTL（qNSB7-1）和穗粒数QTL （qSPP1-1） 已被报道，其余穗部性状QTL尚未报道。

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