5个籼稻背景的高代回交置换系的置换片段分析

以轮回亲本籼稻品种9311（Oryza sativassp.indica‘Yangdao6’）为对照,选用132个亲本间有多态性的SSR标记,对以粳稻品种日本晴（Oryzasativassp.japonica‘Nipponbare’）为供体的5个高代回交置换系的农艺性状及置换片段进行分析。5个置换系在粒长、粒宽、千粒重、剑叶长、株高及落粒性等方面与籼稻品种9311之间有极显著差异,其余性状与籼稻品种9311间的差异不显著;从置换系中检测出8个置换片段,总长度为236.0cM,平均长度为29.5cM;从置换片段上检出包括2个千粒重、1个粒长、1个粒宽、1个剑叶长、1个株高和1个落粒性共7个QTLs,分别分布在水稻第1、3、5、6和第10染色体上。其中,第1染色体上控制剑叶长的QTL和第6染色体上控制株高的QTL可能是新发现的QTLs。实验结果进一步丰富了置换系群体的数量和质量,也为QTLs的精细定位及分子设计育种奠定了基础。

Analysis of Substituted Segments in Five Advanced Backcross Substitution Lines in an indica Background in Rice (Oryza sativa)

Substitution lines are powerful tools for detecting and precisely mapping quantitative trait loci (QTL) in rice. This research involved use of the indica recipient 9311 as the parent and 132 simple sequence repeat markers with polymorphism between parents. We analyzed agronomy traits and substituted segments of 5 advanced backcross substitution lines derived from a backcross of 9311 and a japonica donor, Nipponbare. Compared with 9311, the 5 substitution lines showed statistically signifi-cant differences in grain length, grain width, flag leaf length, plant height and seed shattering. The substitution lines had 8substituted segments, and the total genetic length of the substituted segments was 236.0 cM, mean 29.5 cM. For the recipient 9311and substitution lines, 7 QTLs (2 for 1000-grain weight, 1 grain length, 1 grain width, 1 flag leaf length, 1 plant height and 1 seed shattering) on substituted segments distributed on rice chromosomes 1, 3, 5, 6 and 10 were compared by Student t test. The qFIl-1 on chromosome 1 controlling flag leaf length and the qPh-6 on chromosome 6 controlling plant height are novel QTL. The results enhanced the quantitative and qualitative knowledge of substitution lines, identification of the QTL has laid a foundation for fine-mapping QTL and molecular marker-assisted selection for appearance in rice.