水稻幼苗耐Al3+胁迫的QTL定位分析

用珍汕97B/密阳46构建RIL群体及其遗传图谱，对其种子采用纸培法育苗和培养，并设2个Al³⁺浓度（20 mg/L和30 mg/L）胁迫处理，以处理20 d后的幼苗相对根长（%）和相对苗高（%）为耐Al3+胁迫指标，用于QTL定位分析。结果表明，以相对根长为指标，检测到2个耐Al³⁺胁迫的主效应QTL，即qRAC(r)2和qRAC(r)11，其中qRAC(r)2在2个胁迫处理下均被检测到，有效基因来自于珍汕97B，贡献率较大（12.92%和16.15%），表现出较强的耐Al³⁺胁迫功能。以相对苗高为指标，还检测到qRAC(s)11-2（20 mg/L Al³⁺）和qRAC(s)11-1（30 mg/L Al³⁺）2个主效应QTL，它们均位于第11染色体。耐Al³⁺胁迫的QTL上位性分析还表明，总的QTL上位性互作效应比主效应QTL的作用更大，且显示出相当的复杂性，在不同胁迫浓度下，基因间可以通过不同的互作方式，表现出对高Al³⁺胁迫的耐性。以相对根长为指标，检测到8对上位性互作，涉及1、2、3、5、6、10等6条染色体的15个QTL位点；以相对苗高为指标，共检测到6对上位性互作，涉及第1、2、3、5、6、7、8、9、12等9条染色体；且几乎所有互作均发生在背景因子的QTL位点间。

Analysis of QTLs Mapping of Tolerance to High Al3+ Stress at Seedling Stage in Rice

The recombinant inbred line(RIL) populations derived from Zhenshan 97B/Miyang 46(ZS97B/MY46) and their genetic linkage maps were employed to map QTLs controlling tolerance to high Al~(3 ) stress by using paper culture of rice seedlings with two concentrations of Al~(3 ) stress(20 mg/L and 30 mg/L).After 20 days of treatment,the relative root length (%) and relative seedling height(%) were measured as index for tolerance to high Al~(3 ) stress.The results showed that two QTLs with main effects were detected based on relative root length,i.e.qRAC(r)2 and qRAC(r)11.The former detected in both treatments explained 12.92% and 16.15% of the total phenotypic variation.The positive additive effects came from the female parent,Zhengshan 97B,showing high potential tolerance to high Al~(3 ) stress.Two main effect QTLs were also detected on chromosome 11 by relative seedling height,i.e.qRAC(s)11-2(20 mg/L Al~(3 )) and qRAC(s)11-1(30 mg/L Al~(3 )).Epistasis analysis showed that the variation explained by epistasis QTLs was higher than that explained by the main effect QTLs,indicating that the QTLs displayed their effects through different ways of interaction.Based on relative root length,a total of eight pairs of epistasis including 15 QTLs were detected on six chromosomes(chromosome 1,2,3,5,6 and 10).Based on relative seedling height,a total of six pairs of epistasis were detected on 9 chromosomes(chromosome 1,2,3,5,6,7,8,9 and 12).All the epistasis QTLs were not located at same loci where the main effect QTLs resided.