利用高密度SNP遗传图谱定位小麦穗部性状基因

摘要

Panicle traits of wheat are closely correlated between each other, of them grain number per spike and 1000-grain weight are important components of grain yield. In this study, we mapped quantitative trait loci (QTLs) associated with wheat spike traits using a recombinant inbred line (RIL) population (173 lines of F8:9) derived from a cross of Shannong 01-35 × Gaocheng 9411. The phenotypic data were collected in five environments and the high density genetic map was constructed using 90 k SNP array, DArT technology and traditional molecular markers. In a combination analysis of five environments, many additive QTLs were detected including seven for 1000-grain weight, eight for spike length, three for grain number per spike, five for fertile spikelet number per spike, three for sterile spikelet number per spike, four for spikelet number per spike, and six for spike density. Some QTLs showed high rates of phenotypic variation explained (PVE). For example, the PVE of QTLs for 1000-grain weight on 1B, 4B, 5B, and 6A ranged from 6.00%to 36.30%, with the favorable alleles from the large-grain parent Shannong 01-35;the PVE of QTLs for spike length ranged from 14.34%to 25.44%, and that for sterile spikelet number per spike from 8.70%to 37.70%. In addition to additive loci, 32 pairs of epistatic QTLs were detected, which explained 0.05–1.05%of the phenotypic variations. The marker interval between EX_C101685 and RAC875_C27536 on chromosome 4B showed pleiotropic effects in 1000-grain weight, spike length, grain number per spike, fertile spike number, sterile spikelet number, and spikelet number per spike, with the PVE ranging from 5.40% to 37.70%. There stable main QTLs were detected in multiple environments. Besides, marker interval be-tween wPt-0959 and TaGw2-CAPS on 6A had a locus controlling both 1000-grain weight and spikelet number per spike. These results are valuable in developing molecular markers, fine mapping and cloning genes for spike traits in wheat.%小麦穗部性状之间相关性密切,其中穗粒数和千粒重是重要的产量构成要素,挖掘与穗部性状相关联的基因位点对分子标记辅助育种及解释基因效应具有重要意义。本研究以RIL群体(山农01-35×藁城9411)173个F8：9株系为材料,利用90 k小麦SNP基因芯片、DArT芯片技术及传统的分子标记技术构建的高密度遗传图谱,在5个环境下进行穗部相关性状QTL定位。检测到位于1B、4B、5B、6A染色体上7个控制千粒重的加性QTL,解释表型变异率6.00%~36.30%,加性效应均来自大粒母本山农01-35；检测到8个控制穗长的加性 QTL,解释表型变异率14.34%~25.44%；3个控制穗粒数的加性QTL；5个控制可育小穗数的加性QTL；3个控制不育小穗数的加性QTL,贡献率为8.70%~37.70%；4个控制总小穗数的加性QTL；6个控制小穗密度的加性QTL。通过基因型与环境互作分析,检测到32个加性 QTL,解释表型变异率0.05%~1.05%。在4B染色体区段 EX_C101685–RAC875_C27536检测到控制粒重、穗长、穗粒数、可育小穗数、不育小穗数、总小穗数的一因多效 QTL,其贡献率为5.40%~37.70%,该位点在多个环境中被检测到,是稳定主效QTL。在6A染色体wPt-0959-TaGw2-CAPS区间上检测到控制粒重、总小穗数的QTL。研究结果为穗部性状的分子标记开发、基因精细定位和功能基因克隆奠定了基础。