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【目的】通过对玉米株高和穗位高进行多环境的QTL分析,寻找能够稳定表达的株高和穗位高主效QTL,以为玉米理想株型的分子育种提供理论依据。【方法】以优良玉米自交系许178×K12衍生的150个F7代重组自交系(recombinant inbred lines,RILs)群体为试验材料。首先,从Maize GDB中选取495个SSR标记进行亲本间多态性筛选,利用具有多态性的标记进行群体基因型分析,使用Map Maker V3.0软件划分标记的连锁群并构建遗传连锁图谱。其次,采用Ici Mapping V4.0软件的完备区间作图法(inclusive composite interval mapping,ICIM)进行2年3点(陕西榆林、陕西杨凌、辽宁葫芦岛,2014—2015年)表型值及育种值的株高和穗位高QTL分析。最后,对株高和穗位高进行条件QTL分析,对照非条件QTL分析的结果,探讨株高和穗位高在QTL水平上的遗传关系。【结果】构建的遗传连锁图谱共包含191个SSR标记,图谱全长2 069.1 c M,平均图距10.8 c M。6种环境和育种值中,共检测到10个株高QTL和8个穗位高QTL,分布于第1、3、4、5、6、7、8和10染色体上,LOD介于3.25—8.36,加性效应值介于-6.41—8.70,单个QTL贡献率在6.96%—27.41%。这些QTL中有6个能在3种及以上环境中被检测到,且贡献率大于10.00%,是控制株高和穗位高的主效QTL。位于染色体Bin5.01/5.02区域同一位置的2个QTL在6种环境中被检测到,LOD介于3.25—6.48,加性效应值介于4.05—8.70。位于染色体Bin3.03/3.04区域同一位置的2个QTL在5种环境中被检测到,LOD介于4.71—8.36,加性效应值介于4.93—6.36。位于染色体Bin6.02区域同一位置的2个QTL在3种环境中被检测到,LOD介于3.52—5.21,加性效应值介于4.38—8.16。它们的增效等位基因均来自母本许178。条件QTL分析和非条件QTL分析的结果表明,这3个染色体区域的6个QTL是3个同时控制株高和穗位高的一因多效位点。【结论】玉米株高和穗位高的遗传受环境影响较大,大部分QTL只能在1种或2种环境中被检测到,3个主效QTL可以在3种及以上环境中被检测到,能够稳定地遗传,且贡献率高,有望在分子育种上得到应用。
【Objective】 The aim of this study was to find out QTLs for plant height and ear height that could be stably expressed by QTL analysis of plant height and ear height in order to provide a theoretical basis for molecular breeding of the ideal plant type in maize. 【Method】 A total of 150 F7 recombinant inbred lines (RILs) derived from the elite maize inbred line Xu 178 × K12 were used as experimental materials. First, 495 SSR markers were selected from Maize GDB for polymorphism screening. Polymorphism markers were used for population genotype analysis. Map Maker V3.0 software was used to classify the linkage groups and construct genetic linkage map. Secondly, the phenotypic value and breeding value of YIHA in Shaanxi Province, Yangling in Shaanxi Province, Huludao in Liaoning Province from 2014 to 2015 were calculated by using inclusive composite interval mapping (ICIM) of Ici Mapping V4.0 software. QTL analysis of plant height and ear height. Finally, conditional QTL analysis of plant height and ear height was carried out, and the genetic relationship of plant height and ear height at the QTL level was compared with the results of unconditional QTL analysis. 【Result】 The constructed genetic linkage map contained a total of 191 SSR markers with a total length of 2 069.1 cM and a mean distance of 10.8 cM. Among the six environments and breeding values, 10 QTLs for plant height and 8 QTLs for ear height were detected on chromosomes 1, 3, 4, 5, 6, 7, 8 and 10 with LOD ranging from 3.25- 8.36. The additive effect value ranged from -6.41 to 8.70, and the contribution rate of single QTL was 6.96% -27.41%. Six of these QTLs were detected in three or more environments with a contribution rate greater than 10.00%, and were the major QTLs controlling plant height and ear height. Two QTLs located at the same position on chromosome Bin5.01 / 5.02 were detected in 6 environments with LODs ranging from 3.25 to 6.48 and additive effects ranging from 4.05 to 8.70. Two QTLs located at the same position on chromosome Bin3.03 / 3.04 were detected in five environments with LOD ranging from 4.71 to 8.36 and additive effects ranging from 4.93 to 6.36. Two QTLs located at the same position on chromosome Bin6.02 were detected in three environments with LOD ranging from 3.52 to 5.21 and additive effects ranging from 4.38 to 8.16. Their synergistic alleles are derived from the parental 178. Conditional QTL analysis and unconditional QTL analysis showed that six QTLs in the three chromosome regions were three single-factor multiple-effect sites that simultaneously controlled plant height and ear height. 【Conclusion】 The heredity of plant height and ear height in maize is greatly affected by environment. Most QTLs can only be detected in one or two environments. Three major QTLs can be detected in three or more environments To, can be a stable genetic, and high contribution rate, is expected to be applied in molecular breeding.