小麦-粗山羊草渐渗系千粒重主效QTL qTGW.At-3D的精细定位

Aegilops tauschii, as the D genome donor of common wheat, was regarded as the important gene pool for wheat genetic improvement. Previously, we mapped a major stable QTL qTGW.At-3D for thousand grain weight (TGW) in two consecutive years using two sets of Triticum aestivum - Aegilops tauschii introgression lines including 93 BC1F6 and 204 BC2F5 populations. Then, a high TGW line K542301 homozygous for qTGW.At-3D was selected to cross with Jimai22 to develop secondary populations. The TGW and yield of K542301 were 56.02 g and 625.92 kg which were 13.1% and 7.2% higher than Jimai22, respectively. Using wheat 660K SNP array and 10× sequencing data of two parents and reference genome data of Ae. Tauschii and common wheat, new molecular markers in the target region will be developed to further fine map qTGW.At-3D. Our study will provide genetic resources and marker information to harness the gene pool of Ae. tauschii for wheat high yield breeding.

粗山羊草（Aegilops tauschii, DD, 2n=14）是小麦D基因组的供体，遗传多样性丰富，是小麦抗病、优质和高产等性状遗传改良的重要基因库。本项目利用93份BC1F6和204份BC2F5两个世代的小麦-粗山羊草渐渗系群体，连续两年均定位到千粒重主效QTL qTGW.At-3D。并筛选到在该位点纯合导入的高千粒重株系K542301，该株系的千粒重（56.02 g）比亲本济麦22（49.54 g）增加13.1%，两年小区产量（625.92 kg/亩）比济麦22增加7.2%，并且已经进入山东省品比区试。本研究拟利用该株系与济麦22杂交构建次级分离群体，借助双亲660K SNP芯片和10×重测序数据，并结合粗山羊草和小麦参考基因组序列信息，开发和筛选定位区间内的分子标记，进而精细定位qTGW.At-3D。本项目将为粗山羊草产量相关性状基因的挖掘和利用提供优异材料和标记信息。

作为小麦D基因组的供体，粗山羊草是小麦育种和遗传改良的重要基因库。本试验利用粗山羊草Y215和济麦22杂交构建的93份BC1F6和204份BC2F5两个世代的小麦-粗山羊草渐渗系，在3D染色体上定位到小麦千粒重主效QTL qTGW.At-3D，其增效基因来自于粗山羊草Y215。为进一步精细定位qTGW.At-3D，从渐渗系中鉴定出在目标区段纯合导入的株系K542301，将其与济麦22杂交构建次级分离群体，并且根据双亲660K SNP基因型开发了目标区间内的多个KASP标记，最终将目标基因精细定位在4.9 Mb区间内，同时开发与 qTGW.At-3D 紧密连锁的分子标记，为分子标记辅助育种奠定基础。此外，利用240份粗山羊草重测序结果以及千粒重表型数据，进行基因内的关联分析及单倍型分析，最终获得区间内的5个候选基因。