基于单片段代换系的水稻苗高QTL定位和上位性效应分析

QTL mapping and epistatic effect analysis of seedling height based on single segment substitution lines in rice

【目的】挖掘控制水稻苗高的稳定QTL,并分析其上位性效应,为水稻苗高的分子育种提供QTL和理论参考。【方法】以IR65598-112-2为供体、优良品种‘华粳籼74’为受体的单片段代换系(Single segment substitution line,SSSL)为材料,通过测定SSSL与‘华粳籼74’的苗高差异,对苗高QTL进行定位;通过代换作图缩小QTL的区间,并分析2个苗高QTL的上位性效应。【结果】在第3号染色体长臂端定位到2个相邻的苗高QTLs(qSH3-1和qSH3-2),分别位于第3号染色体的32.59—33.08 Mb和33.16—34.81 Mb区间,长度分别为0.49和1.65 Mb;加性效应分别为-0.86和-1.09 cm;加性效应表型贡献值分别为-4.14%和-5.15%;包含这2个QTL的SSSL的苗高与‘华粳籼74’无显著差异。【结论】本研究定位到2个苗高QTL,这2个QTL之间可能存在显著的上位性。

【Objective】To find out the stable QTLs controlling rice seedling height,analyze their epistatic effects,and provide QTL and theoretical references for molecular breeding of rice seedling height.【Method】The single segment substitution lines(SSSLs)with IR65598-112-2 as donor and‘Huajingxian 74’as receptor were used as materials.The difference of seedling height between SSSL and‘Huajingxian 74’was measured and the QTLs of seedling height were mapped.The QTL interval was narrowed by substitution mapping,and the epistatic effects of two seedling height QTLs were also analyzed.【Result】Two adjacent QTLs(qSH3-1 and qSH3-2)for seedling height were mapped on the long arm of chromosome 3,which were located in the intervals of 32.59−33.08 and 33.16−34.81 Mb,with the lengths of 0.49 and 1.65 Mb,respectively.The additive effects were−0.86 and−1.09 cm,respectively.The phenotypic contribution rate of additive effects were−4.14%and−5.15%,respectively.However,there was no significant difference of seedling height between SSSL harboring these two QTLs and‘Huajingxian 74’.【Conclusion】Two QTLs for seedling height were identified,and there may be significant epistasis effects between the two QTLs.