Genetic dissection of the grain-filling rate and related traits through linkage analysis and genome-wide association study in bread wheat

Wheat grain yield is generally sink-limited during grain filling. The grain-filling rate (GFR) plays a vital role but is poorly studied due to the difficulty of phenotype surveys. This study explored the grain-filling traits in a recombinant inbred population and wheat collection using two highly saturated genetic maps for linkage analysis and genome-wide association study (GWAS). Seventeen stable additive quantitative trait loci (QTLs) were identified on chromosomes 1B, 4B, and 5A. The linkage interval between IWB19555 and IWB56078 showed pleiotropic effects on GFR₁, GFR_max, kernel length (KL), kernel width (KW), kernel thickness (KT), and thousand kernel weight (TKW), with the phenotypic variation explained (PVE) ranging from 13.38% (KW) to 33.69% (TKW). 198 significant marker-trait associations (MTAs) were distributed across most chromosomes except for 3D and 4D. The major associated sites for GFR included IWB44469 (11.27%), IWB8156 (12.56%) and IWB24812 (14.46%). Linkage analysis suggested that IWB35850, identified through GWAS, was located in approximately the same region as QGFRmax2B.3-11, where two high-confidence candidate genes were present. Two important grain weight (GW)-related QTLs colocalized with grain-filling QTLs. The findings contribute to understanding the genetic architecture of the GFR and provide a basic approach to predict candidate genes for grain yield trait QTLs.     

Identification and validation of novel loci associated with wheat quality through a genome-wide association study

Understanding the genetic basis of quality-related traits contributes to the improvement of grain protein concentration(GPC), grain starch concentration(GSC), and wet gluten concentration(WGC) in wheat. In this study, a genome-wide association study(GWAS) based on a mixed linear model(MLM) was performed on 236 wheat accessions, including 160 cultivars and 76 landraces, using a 55K single nucleotide polymorphism(SNP) array in multiple environments. A total of 12 stable QTL/SNPs that control diffe...     

Genetic dissection of wheat uppermost-internode diameter and its association with agronomic traits in five recombinant inbred line populations at various field environments

Uppermost-internode diameter (UID) is a key morphological trait associated with spike development and yield potential in wheat. Our understanding of its genetic basis remains largely unknown. Here, quantitative trait loci (QTLs) for UID with high-density genetic maps were identified in five wheat recombinant inbred line (RIL) populations. In total, 25 QTLs for UID were detected in five RIL populations, and they were located on chromosomes 1A, 1D (3 QTL), 2B (2), 2D (3), 3B, 3D, 4A, 4B (3), 4D, 5A (5), 5B (2), 6B, and 7D. Of them, five major and stable QTLs (QUid.sau-2CN-1D.1, QUid.sau-2SY-1D, QUid.sau-QZ-2D, QUid.sau-SC-3D, and QUid.sau-AS-4B) were identified from each of the five RIL populations in multiple environments. QUid.sau-2CN-1D.1, QUid.sau-2SY-1D and QUid.sau-SC-3D are novel QTLs. Kompetitive Allele Specific PCR (KASP) markers tightly linked to them were further investigated for developing near-isogenic lines (NILs) carrying the major loci. Furthermore, candidate genes at these intervals harboring major and stable QTLs were predicted, and they were associated with plant development and water transportation in most cases. Comparison of physical locations of the identified QTL on the ‘Chinese Spring’ reference genome showed that several QTLs including two major ones, QUid.sau-2CN-1D.1 and QUid.sau-2SY-1D, are likely allelic confirming their validity and effectiveness. The significant relationships detected between UID and other agronomic traits and a proper UID were discussed. Collectively, our results dissected the underlying genetic basis for UID in wheat and laid a foundation for further fine mapping and map-based cloning of these QTLs.     

QTL Mapping for Dough Mixing Characteristics in a Recombinant Inbred Population Derived from a Waxy × Strong Gluten Wheat (Triticum aestivum L.)

Protein and starch are the most important traits in determining processing quality in wheat. In order to understand the genetic basis of the influence of Waxy protein (Wx) and high molecular weight gluten subunit (HMW-GS) on processing quality, 256 recombinant inbred lines (RILs) derived from the cross of waxy wheat Nuomai 1 and Gaocheng 8901 were used as mapping population. DArT (diversity arrays technology), SSR (simple sequence repeat), HMW-GS, and Wx markers were used to construct the molecular genetic linkage map. QTLs for mixing peak time (MPT), mixing peak value (MPV), mixing peak width (MPW), and mixing peak integral (MPI) of Mixograph parameters were evaluated in three different environments. The genetic map comprised 498 markers, including 479 DArT, 14 SSR, 2 HMW-GS, and 3 Wx protein markers, covering 4 229.7 cM with an average distance of 9.77 cM. These markers were identified on 21 chromosomes. Eighteen additive QTLs were detected in three different environments, which were distributed on chromosomes 1A, 1B, 1D, 4A, 6A, and 7D. QMPT-1D.1 and QMPT-1D.2 were close to the Glu-D1 marker accounting for 35.2, 22.22 and 36.57% of the phenotypic variance in three environments, respectively. QMPV-1D and QMPV-4A were detected in all environments, and QMPV-4A was the nearest to Wx-B1. One minor QTL, QMPI-1A, was detected under three environments with the genetic distances of 0.9 cM from the nearest marker Glu-A1, explaining from 5.31 to 6.67% of the phenotypic variance. Three pairs of epistatic QTLs were identified on chromosomes 2D and 4A. Therefore, this genetic map is very important and useful for quality trait related QTL mapping in wheat. In addition, the finding of several major QTLs, based on the genetic analyses, further suggested the importance of Glu-1 loci on dough mixing characteristics.     

小麦骨干亲本“周8425B”及其衍生品种的遗传解析和抗条锈病基因定位

 【目的】利用高密度分子标记解析了周8425B衍生品种的遗传结构,并鉴定其携带的抗条锈病基因。【方法】利用921个DArT（Diversity Arrays Technology）标记和83个SSR标记分析周8425B及其50份衍生品种（系）间的遗传结构和遗传区段传递,并利用关联分析定位抗条锈病基因。【结果】周8425B及其衍生品种的遗传相似性平均为67.6%,聚类分析结果与品种系谱来源基本一致。周8425B对其衍生一代、二代和三代的平均遗传贡献率分别为67.7%、63.6%和58.8%,在A、B和D基因组间遗传贡献率分别为 68.7%、62.0%和 59.4%。周8425B 对其衍生品种的21条染色体贡献率变幅为44.9%—70.9%,其中,对4A染色体贡献率最低,为44.8%,对1D染色体贡献率最高,达79.0%。利用DArT和SSR标记与成株期抗条锈鉴定结果进行关联分析,发现4个条锈病抗性位点（P＜0.01）,其中2个条锈病抗性位点QYr.caas-2BL和QYr.caas-7BL与已报道的抗条锈病基因Yr7和YrZH84在相同染色体区段,另一个抗性位点QYr.caas-1BL与抗叶锈基因LrZH84位置相同,推测该位点与LrZH84紧密连锁或者一因多效。在3A染色体长臂末端发现一个条锈病抗性位点QYr.caas-3AL,与标记wPt-0398关联,可能是一个新基因,能解释22.9%的表型变异。【结论】骨干亲本对衍生后代在基因组和染色体水平上的贡献率主要与重要基因遗传传递有关,衍生品种携带的4个抗条锈病基因均来自骨干亲本周8425B,这些抗性基因及其它优异基因将在黄淮冬麦区南片品种遗传改良中继续发挥重要作用。     

四倍体小麦胚大小性状QTL定位与分析

【目的】挖掘小麦胚大小性状相关的数量性状位点，解析胚大小与其他重要农艺性状之间的相关性，为胚相关性状QTL的精细定位及育种利用奠定基础。【方法】以四倍体小麦矮兰麦（Ailanmai）和野生二粒小麦（LM001）构建的121份F8代重组自交系群体（AM群体）作为研究材料，将其分别种植于成都市崇州试验基地（2018、2019和2020年）、成都市温江区试验基地（2020年）和雅安市试验基地（2020年），调查5个环境下的胚长、胚宽、胚长/胚宽、胚长/粒长、胚宽/粒宽以及胚面积6个性状，结合基于小麦55K SNP芯片构建的遗传连锁图谱对上述6个性状进行QTL定位。【结果】胚大小性状呈近似正态分布，符合数量性状的遗传特征。QTL定位共检测到27个胚大小相关性状的QTL，其中，7个分别控制胚长和胚宽的QTL可解释7.75%—21.74%和7.67%—33.29%的表型变异，共检测到5个在多环境稳定表达的主效QTL:QEL.sicau-AM-3B、QEW.sicau-AM-2B、QEW/KW.sicau-AM-2B、QEL/EW.sicau-AM-2B-1和QEA.sicau-AM-2B，其贡献率...     

硬粒小麦与野生二粒小麦重组自交系群体穗部性状的QTL定位

野生二粒小麦是现代栽培小麦的祖先种,含有极为丰富的遗传多样性。本研究利用来自以色列Gitit的野生二粒小麦G18-16与来自欧洲的硬粒小麦栽培品种Langdon杂交构建的重组自交系F6代152个家系,进行了抽穗期、单株有效穗数、穗粒数、穗长、芒长等数量性状基因位点(QTL)分析,发现全部家系在5个性状上表现出宽广的遗传差异。14个穗部性状加性QTL被定位,LOD值为1.9~13.4,贡献率为7.3%~54.2%。控制抽穗期的QTL共3个,定位在3A(2个)和7B上;在2A(2个)和5A上共找到3个控制穗粒数的QTL;在5B上找到2个控制单株有效穗数的QTL;控制穗长的3个QTL分布在5A(2个)和7A上;在4B,5A和7A上共找到3个控制芒长的QTL。获得的QTL可用于今后分子标记辅助育种改良现代栽培小麦。     

基于55K SNP芯片的普通小麦穗长非条件和条件QTL分析

[目的]进一步挖掘小麦穗长具有利用价值的数量遗传位点(QTL),同时深入探究穗长与其他重要农艺性状之间的遗传关系,为精细定位和分子辅助选择育种奠定基础.[方法]以20828为母本、SY95-71为父本,构建126份F7代重组自交系群体.将亲本及其重组自交系分别于2016-2017年和2017-2018年生长季种植在中国...     

小麦单位面积穗数和粒长主效QTL紧密连锁KASP标记的开发及其效应评价

【目的】小麦单位面积穗数和籽粒粒长是小麦产量相关的重要农艺性状,对其进行遗传改良有利于提高小麦的产量。通过对前期QTL定位鉴定到的提高单位面积穗数的主效QTL位点QSn.sau-2D.2和提高籽粒粒长的主效QTL位点QKl.sau-3D.2开发相应的KASP分子标记,并在川农18和T1208构建的RILs群体中进行验证及评价,为更好地利用这两个QTL以及分子标记辅助育种奠定基础。【方法】利用前期在川农18和T1208构建的高代自交群体中鉴定到的控制小麦单位面积穗数主效QTL位点QSn.sau-2D.2和控制籽粒粒长主效QTL位点QKl.sau-3D.2,结合在这两个QTL区间内的55K SNP分子标记序列,开发设计KASP分子标记,并在亲本间筛选具有多态性的KASP分子标记。将筛选到的KASP分子标记在川农18×T1208的RILs群体中分别进行基因分型和鉴定相应表型性状的高低,并分析这两个主效QTL对于其他农艺性状的影响。【结果】KASP-AX-111151907和KASP-AX-109962767在亲本中具有多态性,KASP-AX-111151907和KASP-AX-1099627...     

中国冬小麦品种籽粒植酸含量差异及其与蛋白质含量的关系(英文)

[目的]分析中国冬小麦籽粒植酸含量差异与蛋白质含量的关系,以期为提高小麦营养品质提供理论依据。[方法]以来自4个麦区的161份小麦品种为材料,分析了籽粒植酸含量变化及分布频率、植酸含量与籽粒形态特征、粒重、蛋白质含量的关系。[结果]结果表明,植酸含量变异范围为0.92%-1.95%,平均值为1.41%;蛋白质含量为12.60%-19.20%,平均为15.24%。籽粒植酸含量的分布呈现正态分布,其中有53.4%的小麦品种植酸含量在1.25%-1.55%之间,只有8.7%的品种植酸含量小于1.1%。相关分析表明,植酸含量与蛋白质含量、SDS沉降值之间无显著相关,但蛋白质含量与沉降值之间呈显著正相关,表明培育低植酸含量且蛋白质含量高的小麦品种理论上是可行的。籽粒千粒重与籽粒宽、长和厚呈显著正相关,但是植酸含量与千粒重、籽粒长、宽、厚之间的相关均未达到显著水平。[结论]在品种选育中,获得低植酸含量、高粒重且加工品质好的小麦品种是可行的。     

普通小麦农大3338×京冬6号DH系群体株高及节间长度的QTL分析

采用普通小麦农大3338和京冬6号的组合构建的包含216个株系的DH系为材料,以包含379个标记的高密度遗传连锁图谱为基础,利用复合区间作图法,通过一年两点田间试验,对株高及其组成成分不同节间长度的QTL进行分析。结果表明,一年两点最终株高共定位到8个QTL,分布在染色体2D,4B,4D,5A,6D,7A上,共解释株高变异为91.86%(北京)、92.63%(临汾)。各节间表型数据总共定位到28个QTL,分布在染色体2B,2D,3B,4A,4B,4D,5A,6A,6D,7A上。这些QTL基本包括了影响最终株高的8个位点,各节间长度还有部分特有的QTL。上述结果为在育种中实现对株高、穗下节长和其他节间长度的精细遗传操作及深入解析株高性状形成的遗传学基础提供了理论依据。     

A major and stable QTL for wheat spikelet number per spike validated in different genetic backgrounds

The spikelet number per spike (SNS) contributes greatly to grain yield in wheat. Identifying various genes that control wheat SNS is vital for yield improvement. This study used a recombinant inbred line population genotyped by the Wheat55K single-nucleotide polymorphism array to identify two major and stably expressed quantitative trait loci (QTLs) for SNS. One of them (QSns.sau-2SY-2D.1) was reported previously, while the other (QSns.sau-2SY-7A) was newly detected and further analyzed in this study. QSns.sau-2SY-7A had a high LOD value ranging from 4.46 to 16.00 and explained 10.21–40.78% of the phenotypic variances. QSns.sau-2SY-7A was flanked by the markers AX-110518554 and AX-110094527 in a 4.75-cM interval on chromosome arm 7AL. The contributions and interactions of both major QTLs were further analyzed and discussed. The effect of QSns.sau-2SY-7A was successfully validated by developing a tightly linked kompetitive allele specific PCR marker in an F_2:3 population and a panel of 101 high-generation breeding wheat lines. Furthermore, several genes including the previously reported WHEAT ORTHOLOG OF APO1 (WAPO1), an ortholog of the rice gene ABERRANT PANICLE ORGANIZATION 1 (APO1) related to SNS, were predicted in the interval of QSns.sau-2SY-7A. In summary, these results revealed the genetic basis of the multi-spikelet genotype of wheat line 20828 and will facilitate subsequent fine mapping and breeding utilization of the major QTLs.     

Genetic dissection of ear-related traits using immortalized F2 population in maize

Ear-related traits are often selection targets for maize improvement. This study used an immortalized F₂(IF₂) population to elucidate the genetic basis of ear-related traits. Twelve ear-related traits(namely, row number(RN), kernel number per row(KNPR), ear length(EL), ear diameter(ED), ten-kernel thickness(TKT), ear weight(EW), cob diameter(CD),kernel length(KL), kernel width(KW), grain weight per ear(GW), 100-kernel weight(HKW), and grain yield per plot(GY)),were collecte...     

盐胁迫下调控小麦苗期性状的QTL分析

【目的】定位盐胁迫下调控小麦苗期性状的QTL位点,为分子标记辅助选择小麦耐盐性状提供基因位点和连锁标记。【方法】以小偃54×京411重组自交系群体为材料,在盐胁迫条件下检测调控小麦苗期MRL、     RDW、SDW和TDW及其相对性状的QTL位点。【结果】共检测到调控小麦苗期4个性状及其相对性状的25个QTL位点,分布在1A、2A、2D、3A、4A、4B、5B、5D、6B、7A和7B共11条染色体上,贡献率在4.4%-25.5%。其中有15个QTL位点成簇分布于3A、4A、4B、5B、5D染色体的5个遗传区间,其余10个QTL位点各自分布于不同的染色体区段。检测到的5个贡献率大于10%的位点分别位于3A染色体的Xgwm497.1-Xcfa2193和4A染色体的Xbarc78-Xgwm350.1。【结论】多数调控小麦耐盐性的QTL位点成簇分布于3A、4A、4B、5B和5D染色体上,3A染色体的Xgwm497.1-Xcfa2193和4A染色体的Xbarc78-Xgwm350.1携带所有5个贡献率在10%以上的QTL位点。     

小麦重组自交系成株抗条锈性QTL分析

 【目的】对小麦成株期条锈病抗性进行数量性状位点（QTL）分析。【方法】以小麦重组自交系内乡188/偃展1号为材料,在连续两年田间充分发病的情况下,分别用病程曲线下面积（Area Under Disease Progress Curve,AUDPC）和反应型（Infection Type,IT）2种病情指标,通过复合区间作图,分析成株抗条锈性的加性QTL、上位性互作及其分别与环境的互作效应（QTL×environment interaction,QE）。【结果】两年共检测到9个加性抗性QTL,其中使用AUDPC和IT共检测到2个相同的QTL;9个QTL中,5个具有环境互作效应。还检测到7对上位性互作的QTL,其中2对具有环境互作效应。采用AUDPC数据,检测到的QTL能够解释表型的62.05%,其中主要为加性效应（44.32%）和上位性互作效应（17.73%）,环境互作很小（0.42%）。采用IT数据,总共检测到的QTL解释了表型变异的37.53%,其中加性效应和上位性互作效应分别解释了23.94%和10.51%,与环境互作解释了3.08%。【结论】内乡188的抗条锈性是由多个位点控制的,在感病亲本偃展1号中也存在抗性QTL;位于3B和6D染色体上的QTL为2个新的成株期抗性条锈位点;非抗性位点间存在上位性互作效应。     

玉米茎秆相关性状多效性QTL检测及相应R程序包编制

利用回归分析、似然比检验、排列检验、参数自助检验和交叉验证等统计分析方法,构建了多系杂交群体多性状QTL定位模型,并编制了配套的R语言程序包,该套模型和R程序包同样适用于两系杂交群体QTL检测和多效性QTL分析。基于本研究的模型和R程序包,以玉米自交系B73和高油突变体Ce03005为亲本产生的216个RIL群体为研究材料,对玉米茎秆相关性状进行多效性QTL检测分析,结果表明:Bin5.03区域内调控最大折断力矩MF和节间直径d的QTL,Bin6.01区域内调控单位体积中性洗涤纤维NDF和节间含水量Wwc的QTL,Bin8.03区域内影响节间干重WD和MF的QTL均为多效性QTL;在5号染色体上,调控d和NDF的QTL与调控MF和NDF的QTL均为连锁的QTL。本研究不仅为玉米茎秆性状的遗传改良提供了参考,也为其他作物遗传育种研究过程中多效性QTL检测提供了软件分析平台。     

宁春4号与河东乌麦杂交F2:5家系的籽粒品质性状及其QTL分析

【目的】分析宁春4号与河东乌麦间杂交F_2:5家系的籽粒品质性状及其重要QTL,为宁夏小麦品质性状的遗传改良提供优异资源。【方法】以主要籽粒品质性状差异较大的宁春4号与河东乌麦及其杂交的248个F_2:5家系为材料,利用方差分析、相关分析、聚类分析和复合区间作图等方法对12个籽粒品质性状及其重要QTL进行研究。【结果】12个籽粒品质性状在F_2:5家系中均出现明显分离,其中,水分含量、吸水率、沉降值、稳定时间和硬度指数的群体平均值均超过高亲亲本,超高亲比例为59.27%~92.74%;粗蛋白含量、湿面筋含量、出粉率和形成时间的群体平均值介于双亲之间,超中亲比例为42.34%~50.81%,超高亲比例为12.50%~27.42%;降落值、拉伸面积和容重的群体平均值均低于低亲亲本,超中亲比例为1.61%~33.87%,超高亲比例为1.61%~31.05%。基于籽粒品质性状的测定结果,在欧氏距离为13时,可将248个家系分为六大类群,其中,类群Ⅱ平均湿面筋含量（32.16%）和降落值（363.55 s）最高,类群Ⅲ平均粗蛋白含量（14.89%）、吸水率（62.88%）、拉伸面积（152.28 cm2）、容重（779.20 g/L）、形成时间（4.15 min）和硬度指数（69.93）均居首位,类群Ⅴ平均水分含量最低（11.68%）、稳定时间最长（13.16 min）,类群Ⅵ平均出粉率（68.86%）和沉降值（41.31 mL）最高。利用69个SSR分子标记构成的39个区间共检测到68个籽粒品质性状QTL,其中,与水分含量、粗蛋白含量、湿面筋含量、出粉率、吸水率、降落值、沉降值、拉伸面积、容重、稳定时间、形成时间和硬度指数相关的QTL数量分别有5、2、4、9、2、12、4、4、1、9、9和7个,分布在1A~7A、1B、2B、3B、6B、1D、2D、3D、6D和7D共16条染色体上,LOD值最大为3.03,表型贡献率为3.17%~43.81%,加性效应为-14.8275~15.3442,同时,1A、2A、4A、7A、2B、3B、6B、1D、2D、3D、6D和7D染色体上检测到多个籽粒品质性状QTL,表明这12条染色体存在QTL富集区。【结论】小麦的大部分品质性状属于多基因控制的数量性状,宁春4号与河东乌麦间杂交F_2:5家系中出现了较多超亲类型,其中类群Ⅲ为籽粒品质性状的最优类群。检测到的68个籽粒品质性状QTL可选择性地用于小麦品质性状的遗传改良。     

小麦籽粒构型与粒重性状的遗传分析

以小麦6044×01-35杂交后获得的重组自交系群体为试验材料,对其籽粒构型与粒重性状予以遗传分析。结果表明,重组自交系群体籽粒构型性状均呈正态分布,均有不同程度的变异;广义遗传力较高的是粒长/粒厚、粒宽/粒厚、粒长/粒宽、粒长和粒宽;由主成分分析来看,对粒重影响最大的依次是粒长、粒长/粒厚、粒宽/粒厚;千粒重与粒长、粒宽和粒厚均呈极显著正相关性,与粒长/粒宽、粒长/粒厚和粒宽/粒厚呈显著负相关;通过逐步回归和通径分析表明,提高千粒重需协调好粒长、粒宽和粒厚的关系,尤其是粒厚。     

小麦重要品质性状的QTL定位

【目的】发掘重要性状的QTL及其分子标记进行小麦品质分子改良。【方法】采用PH82-2/内乡188杂交后代240个F5:6家系,按照Latinized α-lattice设计,2004～2005年度分别种植在河南焦作、安阳和山东泰安。对籽粒蛋白质含量、Zeleny沉降值、和面时间、8分钟带宽、峰值粘度和稀懈值进行测定,利用188个SSR标记和4个蛋白标记构建遗传连锁图谱,采用复合区间作图法（CIM）对上述6个品质性状进行QTL定位。【结果】 籽粒蛋白质含量检测出3个QTL,分布在3A、3B染色体上。在1B、1D和3B染色体上检测到3个控制Zeleny沉降值的QTL,其中位于1B和1D染色体上的QTL在3个地点均检测到,可解释5.5％～17.6％表型变异。发现3个控制和面时间的QTL,分布在1B和1D染色体上,在3个地点均能检测到,贡献率为7.9％～55.3％;检测出8分钟带宽的QTL 5个,其中1B和1D染色体上的QTL在3种环境下均能检测到,贡献率为11.7%～33.9%。发现峰值粘度QTL 4个,分布在1A、1B、3A和7B染色体上;检测出稀懈值QTL 5个,位于1B、4A、5B、6B和7A染色体上。1B染色体上存在同时控制Zeleny沉降值、和面时间、8分钟带宽、峰值粘度和稀懈值的QTL,与最近标记Glu-B3j连锁距离为0.1～0.8cM,说明1BL/1RS易位对这些性状有重要影响;1D染色体上存在同时控制Zeleny沉降值、和面时间和8分钟带宽的QTL,与最近的标记Dx5+Dy10连锁距离为2.5～3.3cM,表明Dx5+Dy10高分子量谷蛋白亚基对这3个性状影响很大。和面时间和8分钟带宽位于1B和1D染色体的QTL以及稀懈值位于1B染色体上的QTL在3个地点均能检测到,具有环境稳定性。【结论】本研究定位的品质性状的标记可作为小麦品质分子育种的工具。