基于高密度遗传图谱的玉米籽粒性状QTL定位

摘要

Kernel size and weight are major determinants of grain yield. For understanding molecular mechanisms of kernel re-lated traits, a recombinant inbred line (RIL) mapping population including 130 families was developed from the cross of two maize elite inbreds, Huangzaosi (HZS) and Mo17. By using the approach of GBS (genotyping-by-sequencing), the high-density genetic map with 1262 bin markers was constructed. QTLs for kernel related traits were identified by stepwise regression (RSTEP-LRT) using Windows QTL ICI-Mapping software under five environments. In total, 30 QTLs were detected under single environment and 11 QTLs were detected under the joint environment. The kernel length major QTL qklen1and the length/width major QTLqklw1 were found in the adjoining regions with a strong genetic effect under three environments. QTLqklen1was located in a region of 210–212 Mb on chromosome 1 with explained 22.60% of phenotypic variance, andqklw1 was located in a region of 207–208 Mb on chromosome 1 with explained 26.79% of phenotypic variance. In addition, for further verification, another introgression population of BC3F1 was developed with Mo17 as the donor parent and HZS as the recurrent parent. The result of the single marker analysis suggested thatqklen1 andqklw1 also had a significantly genetic effect, which is similar to that in the RIL population. The present study provides a good basis for studying genetic mechanism and molecular marker assisted selection for the improvement of kernel related traits in maize.%籽粒大小及百粒重是决定玉米产量的重要因素。为解析籽粒性状遗传基础,本研究以玉米自交系黄早四(HZS)和Mo17为亲本,构建包含130个重组自交系(recombination inbred line, RIL)的RIL群体。基于GBS (genotyping- by-sequencing)技术获得的高密度多态性SNP (single nucleotide polymorphism)位点,构建了包含1262个Bin标记的高密度遗传图谱。采用完备区间作图法,对5个环境条件下的粒长、粒宽、百粒重、粒长/粒宽4个性状分别进行QTL (quantitative trait locus)定位,共检测到30个QTL。利用5个环境性状均值,共检测到11个QTL。其中粒长主效QTL qklen1、粒长/粒宽主效QTL qklw1在3个单环境条件下均被检测到,且定位在第1染色体相邻区域,物理位置分别为210~212 Mb、207~208 Mb,表型贡献率分别为22.60%和26.79%,被认为是控制玉米籽粒形状的主效位点。针对第1染色体207~212 Mb区间,采用成组法t检验,对黄早四(受体)和Mo17(供体)构建的BC3F1回交群体进行单标记分析。结果表明,在 BC3F1群体中 qklen1和 qklw1同样具有显著的遗传效应。本研究结果不仅为分子标记辅助选择籽粒性状提供了实用标记,而且为主效基因的进一步精细定位和候选基因挖掘奠定了基础。