玉米胚大小及其相关性状的QTL分析

QTL Analysis of Maize Embryo Size and Its Related Traits

胚大小在调控玉米籽粒营养组成及籽粒大小方面扮演着重要角色,解析玉米胚大小自然变异的遗传基础对玉米籽粒品质和产量的协同改良具有重要意义。本研究利用由普通玉米自交系B73和高油玉米自交系By804组配的RIL群体,结合高密度的SNP遗传图谱同时对玉米胚大小、籽粒大小和油分等15个性状进行QTL定位分析,共鉴定到82个QTL,包括38个胚大小性状QTL、23个籽粒大小性状QTL和21个油分性状QTL。每个QTL解释的表型变异范围为2.50%~26.32%,平均为7.94%。QTL的置信区间变幅为0.3~52.8 Mb,平均长度为11.6 Mb;置信区间小于5、10和20 Mb的QTL占所有QTL的比例分别为32.9%、58.5%和79.3%。对检测到的QTL位点进行共定位分析鉴定到15个QTL热点区域,其中10个热点区域至少调控胚大小、籽粒大小、油分等三类性状中的两类,5个QTL热点区域只控制一类性状。在上述热点区域内,鉴定到已克隆的控制玉米籽粒油分的主效基因DGAT1-2和影响籽粒发育的基因Dek15。这些结果为玉米籽粒品质改良提供了重要信息。

Maize embryo has a critical role in controlling kernel nutrition components and kernel size.An understanding of the genetic control for the natural variation of maize embryo size will be beneficial to future coordinated improvement of kernel nutrition and grain yield.In this study,we used the RIL population derived from common inbred line B73 and high-oil inbred line By804,combined with high-density SNP genetic map to simultaneously analyze 15 traits including embryo size traits,kernel size traits and kernel oil traits.A total of 82 QTL were identified,including 38 QTL for embryo size traits,23 QTL for kernel size traits and 21 QTL for oil traits.The phenotypic variance explained by each QTL ranged from 2.50%to 26.32%,with an average of 7.94%.The QTL’s confidence interval ranged from 0.3~52.8 Mb,with an average length of 11.6 Mb;QTL with confidence intervals less than 5,10,and 20 Mb accounted for 32.9%,58.5%,and 79.3%of all QTL,respectively.Co-localization analysis of the detected QTL loci identified 15 QTL hotspots,of which 10 hotspots regulate at least two of the 3 classes of traits(embryo size,oil and kernel size),and 5 hotspots only control one class of traits.In the above-mentioned hotspots,the cloned major gene DGAT1-2 that controls maize kernel oil content and the gene Dek15 that affects kernel development were identified.The results of this study can provide references for the improvement of maize grain yield and quality in the future.