利用单片段代换系定位水稻抽穗期QTL

Mapping of Heading Date QTLs in Rice (Oryza sativa L.) Using Single Segment Substitution Lines

抽穗期是水稻品种的重要农艺性状之一,对抽穗期QTL进行定位并研究其遗传效应在水稻育种中是至关重要的。本研究利用以6个水稻品种为供体的52个单片段代换系为试验材料,通过t测验比较单片段代换系与受体亲本华粳籼74之间抽穗期的差异,对代换片段上的抽穗期QTL进行了鉴定。以P≤0.001为阈值共鉴定出20个抽穗期QTL,这些QTL分布于水稻的10条染色体。QTL加性效应值为–5.9～1.1,加性效应百分率为–7.4%～1.4%。有8个QTL被定位在小于10.0cM的区段内。利用1个单片段代换系与华粳籼74杂交发展的F2群体对qHD-3-1进行了定位。在作图群体中,早抽穗和迟抽穗植株数符合3:1的分离比,早抽穗表现为显性。利用微卫星标记将qHD-3-1定位于3号染色体短臂,PSM304和RM569分别位于其两侧,遗传距离分别为2.4cM和5.1cM。

Heading date （HD） is an important agronomic trait in rice. Appropriate heading date is a prerequisite for attaining the desired yield level in rice breeding programs. It is very important for rice improvement to map heading date quantitative trait loci （QTLs）. Single segment substitution lines （SSSLs） containing only one segment of donor chromosome are useful tools for precise mapping of QTLs and for the evaluation of gene action. In this research, the QTLs for heading date on the substituted segments of 52 rice SSSLs derived from 6 advanced backcrosses were identified through t-test for means comparisons between SSSLs and the recipient parent Huajingxian 74. QTLs were detected with a significance of P≤0.001. A total of 20 QTLs were identified on 10 rice chromosomes with the exception of chromosomes 5 and 6. The QTL additive effect ranged from -5.9 to 1.1, and the additive effect percentages of the QTLs ranged from -7.4% to 1.4%. Eight QTLs were mapped in intervals less than 10.0 cM. qHD-3-1, a dominant gene for early heading, has been mapped using a F2 population developed from a cross between a SSSL and Huajingxian 74. In mapping population the segregation ratio of early and late heading plants was in accordance with 3：1. qHD-3-1 was located between microsatellite markers PSM304 and RM569 on the short arm of chromosome 3 at genetic distances of 2.4 cM and 5.1 cM, respectively.