小麦染色体2DS雌性育性位点的连锁不平衡分析

小麦生态遗传型雌性不育系XND126的育性受两对主效基因和微效多基因联合控制。通过SSR分子标记连锁分析,在2DS上定位了一个主基因位点。为了精细定位该位点,并验证其真实性,在59个育性正常的普通小麦品种（系）与XND126组成的较小自然群体中,用2DS参考连锁图上的14对SSR研究了标记与位点间的连锁不平衡（LD）程度,发现所有标记均存在LD现象,并找到了与XND126多态性高的品种（系）,作为进一步精细定位的研究材料。依据连锁分析结果,对260个品种（系）与XND126组成的较大自然群体的连锁不平衡研究发现,主效基因位点与其最近的标记Xbarc95间的LD值最大,LD衰减在大群体中同样存在,进一步表明雌性育性主基因位点的确存在于2DS。提示利用连锁分析和关联分析相结合策略进行QTI。精确定位是一种有益的尝试。     

小麦雌性育性与SSR分子标记的关联分析

为了寻找与小麦雌性育性紧密关联的SSR分子标记,并估算其表型效应,选择均匀分布于小麦基因的63个SSR标记,对包括小麦雌性不育系XND126在内的261个品种(系)组成的群体进行分析,并使用STRUCTRE软件进行群体结构评估,利用TASSEL软件的GLM模型检测多态性标记与小麦雌性育性(国内法育性D.F.和国际法育性I.F.)两种表型值的关联程度.结果表明:目标群体中存在3个亚群.基因组中多态性标记关联分析初步显示,标记Xcfd36(2AS、2DS)和Xcfd88(4AL)与小麦雌性育性两种表型值相关联,两个标记对D.F.和I.F.的效应分别是0.1585,0.113和0.087,0.0596.进一步分析发现2DS和4AL连锁群上存在一些与小麦雌性育件更加紧密关联的标记,如Xwmc25(2DS)和Xwmc232(4AL),其效应分别可达到0.5833和0.2841,而2AS上未找到独有的关联标记.分析认为小麦染色体2DS和4AL各存在一个控制雌性育性的基因位点,其中2DS上的QTL被连锁分析所证实.对与表型紧密关联的标记的鉴别对于小麦雌性育性QTL发掘的重要作用进行了探讨.     

黄瓜雌性性状的QTL定位分析

以黄瓜雌性系D0420×强雄性系D06103的211株F2单株为作图群体,应用SSR分子标记进行多态性筛选,得到与黄瓜雌性性状相关的标记位点21个,分属4个连锁群,连锁群全长为98.5 cM,标记间平均距离4.9 cM,最短的连锁群0.5 cM(LG1),最长的连锁群53.4 cM(LG2);标记间最小的遗传距离0.2 cM,最大的遗传距离25.2 cM;采用复合区间定位分析,检测到与黄瓜雌性性状相关的QTL位点2个,均位于第3连锁群上,距离最近标记的遗传距离分别为2.1和1.4 cM,LOD值分别为50.04和6.48,贡献率分别为15.36%和5.69%.     

小麦基因组中与雌性育性关联标记的初步扫描

[目的]发掘与小麦雌性育性紧密关联的SSR分子标记,并估算其表型效应。[方法]选择遍布基因组的40个多态性标记,对包括小麦雌性不育系的261个小麦品种（系）组成的目标群体使用STRUCTRE软件进行群体结构评估,并利用TASSEL软件的GLM模型检测40个多态性标记与小麦雌性育性D.F.（国内法育性）和I.F.（国际法育性）2种表型值的关联程度,确定入选标记。[结果]群体结构评估表明,目标群体中存在3个亚群。基因组多态性标记关联分析结果显示,标记Xcfd36（2AS、2DS）和Xcfd88（4AL）与小麦雌性育性2种表型值相关联,2个标记对D.F.和I.F.的效应分别是0.1585、0.113和0.087、0.0596。[结论]2DS、4AL和2AS可能存在控制小麦雌性育性的QTL。与表型紧密关联的标记的鉴别对于小麦雌性育性遗传机制的研究具有重要的意义。     

小麦雌性不育基因的SSR多态性标记

以普通小麦新601×雌性不育小麦XND126的F2群体作为育性调查以及基因标记群体。通过对育性基因的分析,确定在此组合中雌性不育基因表现为1对主效基因控制;结合混合分组分析法(Bulk Segregant Analy-sis,BSA),首次对小麦雌性不育基因进行了SSR标记研究,通过对一千对微卫星引物的筛选,初步确定了微卫星引物cfd36和gwm296与主效基因连锁。     

小麦雌性育性遗传的分离分析

为了全面了解小麦雌性育性的遗传模式,选用普通小麦中6个育性及结实正常的品种与小麦雌性不育突变系XND126杂交构建6个组合,对6组合P_1、P_2、F_1和F_2充分授粉下的雌性育性进行3种育性表示方法的调查,利用数量性状主基因+多基因混合遗传模型的4世代联合分析方法对其表型数据进行分离分析.结果表明:小麦雌性育性受2对主基因和多基因联合控制,2对主基因之问存在互作效应,不同生态型的组合所估算的主基因遗传率大小不同.并对小麦雌性育性遗传变异方式及其在育种实践中的"双向选择策略"进行了探讨.     

小麦有效分蘖QTL分析

小麦具有分蘖成穗的特性,单株有效分蘖数是构成小麦产量的重要因素之一。以旱选10号×鲁麦14的DH群体为试材,分别在干旱胁迫和正常灌溉条件下对小麦有效分蘖数性状进行QTL定位,应用基于混合线性模型的复合区间作图法分析控制小麦有效分蘖性状的QTL位点。结果表明,共检测到5个加性QTL,分别位于1D,2B,2D,6B,7B染色体上,LOD值介于4.02~6.09,贡献率为8.87%~12.77%;检测到2对上位性QTL,分别位于1D-6A,6D-6B染色体上,LOD值分别为6.87,7.54,贡献率分别为3.27%,37.82%。     

蚕豆遗传图谱与QTL定位研究进展

作为一种粮食、蔬菜、饲料、绿肥兼用的食用豆类,蚕豆在人类健康、土壤改良等方面发挥了重要作用.高密度遗传图谱的构建是蚕豆基因组研究的基础和主要手段,至今共构建了24张蚕豆遗传图谱,最为饱和的图谱覆盖长度为1439 cM,平均遗传距离为0.8 cM.同时基于图谱开展了产量相关性状、品质相关性状以及抗性相关性状的QTL定位,...     

黄瓜单性结实性状的QTL定位

【目的】黄瓜是世界十大蔬菜之一,单性结实是与黄瓜产量和品质密切相关的重要性状。对黄瓜单性结实进行研究,探明全雌性单性结实性状的遗传规律,并进行QTL定位,为进一步了解其分子机理和标记辅助育种奠定基础,也为黄瓜单性结实性状改良提供理论依据。【方法】试验采用对单株主、侧蔓各夹8朵雌花,待所有单株夹花结束后8-10 d一次性调查单性结实座瓜的方法,通过计算单性结实百分率（单性结实瓜数/所夹雌花数×100%）来评价单性结实能力。利用全雌单性结实材料EC1和雌雄同株非单性结实材料8419、14519分别构建的F₂群体进行遗传分析。以EC1×8419杂交得到的部分F₂为作图群体,利用9930和gy14黄瓜全基因组测序开发的1 335对SSR标记和双亲重测序开发的143对Indel标记引物进行多态引物筛选,采用JionMap4.0软件进行遗传图谱构建,以该配组F_2﹕3家系群体为研究对象,利用WinQTLcart2.5软件进行单性结实QTL检测。运用生物信息学的分析方法对初定位主效QTL区间进行候选基因分析。【结果】试材EC1的单性结实遗传符合数量性状的特征,但与不同材料配组的后代群体分离偏向不同亲本。构建了一张含有7条染色体、116个SSR标记和9个Indel标记的连锁图谱,图谱总长度为802.9 cM,标记间平均距离6.3 cM。共检测到7个与单性结实相关的QTL,分别为Parth1、Parth2-1、Parth2-2、Parth3-1、Parth3-2、Parth5、Parth7,分布在1、2、3、5、7染色体上。其中仅Parth2-1在春、秋两季中均被检测到,LOD值分别为9.0和6.2,贡献率为17.4%和10.2%,位于标记SSR00684-SSR22083之间,认为是控制单性结实的主效QTL位点。该区段的遗传距离为17.1 cM,物理距离2.9 Mb,包含307个基因,推测参与植物激素信号转导的基因Csa2M035330.1和Csa2M070880.1是与单性结实相关性较大的候选基因。其他位点都为微效位点。【结论】单性结实的遗传符合数量性状特征,位于2号染色体上的Parth2-1是控制黄瓜单性结实性状的主效QTL位点。推测植物激素代谢通路中的基因是可能的候选基因。研究结果为单性结实主效基因的精细定位和克隆及分子标记辅助育种奠定了基础。     

基于90K芯片SNP标记的小麦遗传图谱构建及抗纹枯病QTL定位

为挖掘定位小麦抗纹枯病QTL,以莱州953×山农辐63的F_(2∶3)为作图群体,用Illumina Wheat 90K芯片检测F_2单株的基因型,并用QTL IciMapping 4.1软件绘制该群体的遗传连锁图谱;在自然发病条件下,鉴定分离群体的抗、感表型,利用QTL IciMapping 4.1进行抗纹枯病QTL定位分析。结果表明,构建的小麦遗传连锁图谱包含21个连锁群,覆盖了小麦的21条染色体,图谱总长度5 528.12 cM,平均图距5.25 cM;共检测到6个分布于小麦1A、1B、2A、3A、7A和7D染色体上的加性QTL位点,单个QTL的贡献率为3.24%～10.37%。该结果可为小麦抗纹枯病QTL精细定位与相关基因克隆奠定基础,也为小麦抗纹枯病分子标记辅助选择育种提供了理论依据。     

QTL for grain yield and yield parameters in winter wheat(Triticum aestivum L.)

Field trials with a set of 108 doubled haploid lines(DHs) derived from a cross between the Chinese winter wheat cvs.CA9613 and H1488 were run at Beijing(China).Phenotypic data were recorded for major agronomic yield traits,i.e.grain weight per ear,grain number per ear and thousand grain weight(Tgw) in two field trials at Beijing.Based on the phenotypic data and a genetic map comprising 168 SSR markers,an analysis of quantitative trait loci(QTL) was carried out for yield and yield parameters using the composite interval mapping(CIM) approach.A total of 14 QTL were detected for these traits across two environments.Four of these QTL located on chromosomes 1A and 2B,respectively,exhibited pleiotropic effects.Loci showing pleiotropic effects will be very useful for understanding the homeologous relationships of QTL and designing an appropriate marker-assisted selection programme by multi-trait selection in order to accumulate("pyramide") favorable alleles at different loci.     

Genetic analysis and QTL mapping of a novel reduced height gene in common wheat(Triticum aestivum L.)

Low stature in wheat is closely associated with lodging resistance, and this impacts harvest index and grain yield. The discovery of novel dwarfing or semi-dwarfing genes can have great significance for dwarf wheat breeding. In this study, we identified an EMS-induced dwarf wheat mutant JE0124 from the elite cultivar Jing411. JE0124 possesses increased stem strength and a 33% reduction in plant height compared with wild type. Gibberellic acid(GA) treatment analysis suggested that JE0124 was GA-sensitive. Analysis of the frequency distribution of plant height in four F2 populations derived from crosses between JE0124 and the relatively taller varieties Nongda 5181 and WT indicated that the dwarfism phenotype was quantitatively inherited. We used two F2 populations and 312 individuals from the reciprocal cross of Nongda 5181 and JE0124 to map the quantitative trait locus(QTL) for reduced height to a 0.85-cM interval on chromosome 2 DL. The mapping was done by using a combination of 660 K SNP array-based bulked segregant analysis(BSA) and genetic linkage analysis, with logarithm of odds(LOD) scores of 5.34 and 5.78, respectively. Additionally, this QTL accounted for 8.27–8.52% of the variation in the phenotype. The dwarf mutant JE0124 and the newly discovered dwarfing gene on chromosome 2 DL in this study will enrich genetic resources for dwarf wheat breeding.     

QTL mapping of seedling biomass and root traits under different nitrogen conditions in bread wheat(Triticum aestivum L.)

Plant nitrogen assimilation and use efficiency in the seedling's root system are beneficial for adult plants in field condition for yield enhancement. Identification of the genetic basis between root traits and N uptake plays a crucial role in wheat breeding. In the present study, 198 doubled haploid lines from the cross of Yangmai 16/Zhongmai 895 were used to identify quantitative trait loci(QTLs) underpinning four seedling biomass traits and five root system architecture(RSA) related traits. The plants were grown under hydroponic conditions with control, low and high N treatments(Ca(NO_3)_2·4H_2 O at 0, 0.05 and 2.0 mmol L~(-1), respectively). Significant variations among the treatments and genotypes, and positive correlations between seedling biomass and RSA traits(r=0.20 to 0.98) were observed. Inclusive composite interval mapping based on a high-density map from the Wheat 660 K single nucleotide polymorphisms(SNP) array identified 51 QTLs from the three N treatments. Twelve new QTLs detected on chromosomes 1 AL(1) in the control, 1 DS(2) in high N treatment, 4 BL(5) in low and high N treatments, and 7 DS(3) and 7 DL(1) in low N treatments, are first reported in influencing the root and biomass related traits for N uptake. The most stable QTLs(RRS.caas-4 DS) on chromosome 4 DS, which were related to ratio of root to shoot dry weight trait, was in close proximity of the Rht-D1 gene, and it showed high phenotypic effects, explaining 13.1% of the phenotypic variance. Twenty-eight QTLs were clustered in 12 genetic regions. SNP markers tightly linked to two important QTLs clusters C10 and C11 on chromosomes 6 BL and 7 BL were converted to kompetitive allele-specific PCR(KASP) assays that underpin important traits in root development, including root dry weight, root surface area and shoot dry weight. These QTLs, clusters and KASP assays can greatly improve the efficiency of selection for root traits in wheat breeding programmes.     

Conditional and unconditional QTLs mapping of gluten strength in common wheat(Triticum aestivum L.)

Dissecting the genetic relationships among gluten-related traits is important for high quality wheat breeding. Quantitative trait loci(QTLs) analysis for gluten strength,as measured by sedimentation volume(SV) and gluten index(GI),was performed using the QTLNetwork 2.0 software. Recombinant inbred lines(RILs) derived from the winter wheat varieties Shannong 01-35×Gaocheng 9411 were used for the study. A total of seven additive QTLs for gluten strength were identified using an unconditional analysis. QGi1 D-13 and QSv1 D-14 were detected through unconditional and conditional QTLs mapping,which explained 9.15–45.08% of the phenotypic variation. QTLs only identified under conditional QTL mapping were located in three marker intervals:WPT-3743–GLU-D1(1 D),WPT-7001–WMC258(1 B),and WPT-8682–WPT-5562(1 B). Six pairs of epistatic QTLs distributed nine chromosomes were identified. Of these,two main effect QTLs(QGi1 D-13 and QSv1 D-14) and 12 pairs of epistatic QTLs were involved in interactions with the environment. The results indicated that chromosomes 1 B and 1 D are important for the improvement of gluten strength in common wheat. The combination of conditional and unconditional QTLs mapping could be useful for a better understanding of the interdependence of different traits at the QTL molecular level.     

小麦戊聚糖研究进展

戊聚糖是小麦籽粒中非淀粉多糖的主要成分.戊聚糖在小麦籽粒中的含量较低,但它对小麦的营养品质和加工品质都有重要的影响.本文综述了近年来国内外关于小麦戊聚糖的最新研究进展,包括小麦品种间戊聚糖含量的变异、戊聚糖的影响因素和遗传特性、戊聚糖与农艺性状关系及戊聚糖对小麦品质的影响等,旨在为中国小麦品质改良提供依据.     

小麦磷利用效率研究进展

小麦是我国主要的粮食作物之一,需求量大,施用磷肥对提高小麦的产量具有举足轻重的作用。因此,开展小麦磷利用效率相关的基础与应用研究具有重要意义。本文从磷利用效率的定义、植物对低磷胁迫的适应机制、相关基因的克隆、小麦磷利用效率的影响因素、磷高效基因型的评价和筛选、小麦磷利用效率及相关性状的QTL分析6个方面进行简单概述,并提出了今后小麦磷素利用效率研究的方向和重点。     

小麦产量构成因素的基因效应和杂种优势分析

为提高对小麦产量构成因素的选择效率,以7个半冬性小麦品种及按7×7双列杂交设计的21个F1杂交组合在2个地点的试验资料,研究了小麦2个产量构成因素—每穗粒数和千粒质量的基因效应和杂种优势。结果表明,每穗粒数和千粒质量的遗传符合加性-显性模型,基因显性效应的作用远大于其加性效应,显性程度为超显性。增效基因为显性,减效基因为隐性。每穗粒数和千粒质量在2个试点的平均狭义遗传力分别为54.00%和63.17%。每穗粒数和千粒质量表现正向的平均杂种优势和超亲优势,变异幅度较大,并在基因型、地点及基因型与地点互作间存在极显著差异。     

Breeding for drought tolerance in wheat (Triticum aestivum L.): constraints and future prospects

This review article is based on different aspects of wheat breeding for drought tolerance. Drought is regarded as one of the most serious threats to agriculture in Pakistan. Therefore, breeding for drought tolerance must be given top priority. Here, we try to study various options available to wheat breeders exploring the underlying mechanisms of drought tolerance. The progress made in conventional and non-conventional (molecular) based approaches with potential findings and constraints are reviewed in this article. Equipped with such information, it will be possible for breeders to further explore the mysteries of drought tolerance and to select genotypes with an improved yield under water-deficit conditions.     

小麦粒长和粒宽的QTL定位分析

【目的】粒长、粒宽是小麦种子重要的形态性状,该性状对籽粒的外观商品品质、产量及磨粉品质均至关重要,研究不同环境条件下小麦粒长、粒宽的单个标记和复合区间作图的QTL定位,对小麦粒长、粒宽的分子标记辅助选择具有重要参考作用。【方法】应用一个由115个系组成的W7984/Opata 85重组自交系(RIL)群体,建立了由394个DNA分子标记组成的遗传连锁图,在2种不同环境条件下对小麦粒长、粒宽进行了单个标记的回归分析和复合区间作图的QTL定位。【结果】在单个标记的回归分析中检测到5个粒长的QTLs、3个粒宽的QTLs;复合区间作图分析结果表明,控制粒长的QTLs分别位于5BL和7DS上,在5BL上的贡献率为20.20%~20.81%,LOD值为4.50~4.55;在7DS上的贡献率为13.54%~13.91%,LOD值为2.94~3.20。控制粒宽的QTL位于2B上,贡献率为13.71%~19.30%,LOD值为2.98~4.18。【结论】位于5B和7D上的控制粒长的QTL和位于2B上的控制粒宽的QTL在2种条件下均能检测到。     

Genome-wide association analysis for stripe rust resistance in spring wheat(Triticum aestivum L.) germplasm

Stripe rust is a continuous threat to wheat crop all over the world. It causes considerable yield losses in wheat crop every year. Continuous deployment of adult plant resistance(APR) genes in newly developing wheat cultivars is the most judicious strategy to combat this disease. Herein, we dissected the genetics underpinning stripe rust resistance in Pakistani wheat germplasm. An association panel of 94 spring wheat genotypes was phenotyped for two years to score the infestation of stripe rust on each accession and was scanned with 203 polymorphic SSRs. Based on D' measure, linkage disequilibrium(LD) exhibited between loci distant up to 45 c M. Marker-trait associations(MTAs) were determined using mixed linear model(MLM). Total 31 quantitative trait loci(QTLs) were observed on all 21 wheat chromosomes. Twelve QTLs were newly discovered as well as 19 QTLs and 35 previously reported Yr genes were validated in Pakistani wheat germplasm. The major QTLs were QYr.uaf.2 AL and QYr.uaf.3 BS(PVE, 11.9%). Dissection of genes from the newly observed QTLs can provide new APR genes to improve genetic resources for APR resistance in wheat crop.