玉米百粒重主效QTL（Hgw1q1）克隆及分子机理解析

郑单958为我国推广面积第一的杂交品种，其亲本郑58和昌7-2的选育和组配是育种家新品种选育的重要参考标准。然而近些年来能够完全超越郑单958的新品种和亲本始终无法取得突破，其根本原因在于郑单958产量形成过程中关键基因的克隆和遗传解析不清楚。申请人在前期构建了大群体的郑单958F2分离群体，鉴定到遗传稳定且表型贡献率较高的玉米百粒重主效QTL（Hgw1q1），在此基础上，拟利用残余杂合子的方法，通过多代自交结合二代测序的方法，快速纯合主效QTL位点外的杂合位点，精细定位主效QTL位点。进而利用分子遗传学、转录组学和分子生物学等方法克隆Hgw1q1，解析其参与的遗传调控网络，为深入研究郑单958超级品种内在的杂种优势作用模式提供理论基础。同时开发连锁的分子标记，进一步导入主效QTL到黄淮海核心种质资源中，为创制强优势玉米新品种奠定基础。

The cultivar Zhengdan 958, which is the F1 plant from the cross between two inbred parental lines Chang7-2 and Zheng58, displays a high yield performance and is the most widely grown hybrid in China. However, few new hybrids with better performance than Zhengdan 958 have been cultivated during these years, the reason for which was the unclear mechanism of key regulatory network controlling high yield performance of Zhengdan 958, Based on our previous studies, a genetically stable major QTL (Hgw1q1), controlling maize hundred-kernel weight, was identified and explained a high phenotypic variance in the large segregated F2 population of Zhengdan 958. By utilizing the F2 populations, the residual heterozygous strategy will be applied to fine mapping the major QTL, and the other heterozygous loci will be purified across the whole genome by multi-generation selfing and resequencing technologies. Additionally, the Hgw1q1 gene will be cloned by integrating the molecular genetics, transcriptomic and molecular biology methods, thus deciphering the genetic regulatory network and providing a genetic basis of the heterosis in Zhengdan 958. Besides, the linkage molecular markers will be developed to help backcross the identified major QTL into elite germplasm resources of Huanghuaihai region. This study highlights candidate genetic regulatory network controlling maize hundred-kernel weight and provides targets for breeding applications.