SSR和SRAP标记研究油菜杂交种骨干亲本的遗传多样性

用SSR和SRAP两种分子标记方法研究51份甘蓝型油菜杂交种亲本系的遗传多样性,并对两种分子标记研究结果进行比较。结果发现,在51份材料中,45对SSR引物共扩增出194条多态性条带,平均每对引物为4.3条,25对SRAP引物共扩增出197条多态性条带,平均每对引物为7.9条。UPGMA聚类分析表明,SSR和SRAP标记都可将51份亲本材料划分为五大类群,本所选育的玻里马细胞质雄性不育系（Polima CMS）的主要保持系和恢复系都聚在同一类群的不同亚群中。根据系谱资料分析发现,SRAP标记划分的类群与系谱资料更为接近,SRAP标记更适用于遗传关系较近材料的遗传多样性分析。SRAP标记揭示的亲本间遗传距离要大于SSR标记揭示的遗传距离。两种不同标记方法揭示出油菜亲本遗传多样性的差异主要是由不同的标记方法揭示的标记位点等位基因变异数不同造成的。     

基于抗病功能基因标记的中国三系杂交水稻骨干亲本遗传多样性研究

为探究实现水稻广谱持久抗性育种,以及水稻病害的有效防治,本研究利用文献中报道的与抗稻瘟病及白叶枯病相关的43个功能基因相关标记,研究了76个中国籼型(Oryza sativa ssp.indica)三系杂交水稻骨干亲本的遗传多样性。结果显示,36个标记具有多态性,多态性位点百分率(P)81.81%,共检测到87个等位基因位点;其中有效等位基因(Ne)61.96个,占71.22%,Nei’s遗传多样性指数(He)变幅为0.358~0.974,平均值0.629。76份材料间的遗传相似系数(Gs)变幅为0.341~0.925,平均值0.550。采用UPGMA法进行聚类分析,在遗传相似系数0.624处分为保持系和恢复系两类。保持系和恢复系间的遗传分化系数(Fst)为0.158,呈高度遗传分化,Nei遗传距离(D)0.201。结果显示,功能基因相关标记具有较高的DNA多态性检测效率,用于类群划分和种质资源的多样性分析等方面更具准确性和可靠性;中国三系杂交稻骨干亲本在43个功能基因位点的亲缘关系较近,遗传基础狭窄,同源性较高。但保持系群和恢复群系间在这些功能基因位点的遗传差异较大,遗传分化程度较高。研究结果提示,所研究材料在DNA水平存在丰富的杂种优势利用空间,特别随着更多更细的功能基因位点的发掘,为水稻分子辅助抗性选育以及病害防治提供了有效的实现途径。     

利用RAPD和SSR标记分析陆地棉种质资源的遗传多样性*

遗传多样性的量化与分类是收集和利用种质资源的重要前提。利用随机扩增多态性（RAPD）和简单重复序列(SSR)两种分子标记对31份陆地棉(Gossypium hirsutum L.)种质资源进行了遗传多样性分析,其中14份材料最近从美国和伊朗引进。研究的目标是对这些陆地棉种质资源进行遗传聚类分析,为制定引进资源的利用策略提供参考。从有多态性的21个RAPD引物和18对SSR引物中共获得117个多态性位点。利用NTSYS-pc2．10统计分析软件,采用Jaccard′s相似系数UPGMA法进行聚类。结果表明,中国的17份材料部分聚为一类,国外的14份材料大部分聚为另一类,其它材料相间排列。分别对31份材料的相似系数与中国的17份材料的相似系数进行了比较分析,中国材料相对于新引进的国外材料的遗传多样性水平稍高,与国外材料之间的遗传差异较大。这说明扩大不同地区间种质资源的交流和引进种质资源可以丰富本地材料的遗传多样性。     

我国部分地区小麦叶锈菌遗传多样性的SSR分析

小麦叶锈菌(Puccinia triticina)引起的小麦叶锈病是小麦上的重要病害。为了解小麦叶锈菌遗传多样性及其亲缘关系,本研究利用简单重复序列(simple sequence repeat,SSR)标记技术对2009年采自河北、河南、山东、四川4省的小麦叶锈菌株进行SSR分析。小麦叶锈菌的观察等位基因数(Na)为1.75,有效等位基因数(Ne)为1.40,Shannon信息指数(I)为0.35,Nei’s基因多样性指数(H)为0.23,多态性百分率为75.29%,其中河北、河南和山东的叶锈菌群体遗传多样性水平高于四川群体。聚类分析表明,在相似系数0.96处4个群体聚为2组,河南、山东及四川群体聚为一组,河北群体自成一组,其中河南和山东群体亲缘关系最近。小麦叶锈菌具有一定的遗传变异,群体间遗传变异占总变异的8.93%,群体内遗传变异占总变异的91.07%。小麦叶锈菌群体间每代迁移数Nm为6.10。小麦叶锈菌遗传多样性丰富,群体间遗传相似性较高,亲缘关系与地理分布具有一定相关性。群体内遗传变异是群体遗传变异的主要来源。本研究说明群体间存在广泛的菌源交流,为明确小麦叶锈病流行区系和叶锈菌传播路线提供了基础资料。     

大麦SSR标记遗传多样性及群体遗传结构分析

为了确定大麦亲本材料间的亲缘关系,为后期关联分析奠定基础,本研究利用71个SSR标记对不同来源的99份大麦材料进行了遗传多样性及群体遗传结构分析。结果表明,71个SSR标记共检测到184个等位变异,变幅为2-5个,平均每个标记有2.6个。Shannon指数变幅为0.0565~1.2241,平均值为0.6086。标记多态性信息含量(PIC)的变幅介于0.0200~0.6633之间,平均值为0.3729。聚类结果表明,试验品种的遗传相似系数(GS)的变异范围为0.5109~0.9511,平均值为0.7202。GS值在0.7100水平上分为5大类,分别包括5、4、3、6和79份材料;主坐标分析将材料分为5个亚群,分别包括5、10、12、24和26份材料。群体遗传结构分析将材料分为5个亚群,分别包含24、18、6、22、29份材料。     

我国甘蔗亲本遗传多样性的AFLP标记分析

采用15对多态性较好的AFLP引物对我国自育的78个甘蔗亲本材料遗传多样性进行分析,结果表明,每对引物的多态性位点平均为65．67,多态陆位点率为82．55％。78个甘蔗亲本的遗传相似系数在0．4535～0．8927之间,平均为0．6821。相同组合后代的遗传相似系数较高,平均为0．7656。以遗传相似系数阈值约为0．700划分,聚类分析把78个亲本分为7大类,系谱记录中亲缘关系密切的亲本品系,大多数都能归为同一类。遗传多样性指数分析显示,不同年代亲本多样性指数差异明显,20世纪80年代最高,为0-3185,70年代最低,为0．2645;不同省区的亲本遗传多样指数变化更显著,在0．1952～0．2999之间,广东最高,云南最低。     

黑龙江省春小麦品种遗传多样性的SSR分析

本研究利用微卫星标记(SSR)技术对黑龙江省小麦品种的遗传多样性进行了分析。12对具有多态性的SSR引物在114份小麦品种中共检测到46个等位位点,每对引物检测到的等位位点数为3~8个,平均为3.8个,平均遗传距离为0.7331。不同育种单位的小麦平均遗传距离有较大差异,最大差距为1.30倍。在对不同年代小麦品种的遗传距离分析时发现,随年代的增加,遗传距离逐渐减小,且衰减速度呈加快趋势。聚类分析将114个春小麦品种大致分为3个类群,9个亚类群,较好地反映了品种之间的亲缘关系。     

利用SSR标记分析柑橘雄性不育及低育资源的遗传多样性

采用SSR标记分析了43份柑橘(Citrus)不育、低育、含不育胞质及13份可育材料的遗传多样性。结果表明,8对SSR引物扩增得到35个等位基因,平均每个位点有4.4个等位基因。利用NTSYSpc2.10统计分析软件,UPGMA法聚类分析表明,56份柑橘资源可分为3组。宽皮柑橘类品种为第一组,甜橙、葡萄柚、椪柑及杂柑类品种为第二组,包含不育胞质的澳洲指橘为第三组。SSR聚类分析还表明本地广橘与温州蜜柑有着紧密的亲缘关系,而与早橘、槾橘、本地早等的亲缘关系较远?涕?不育与低育资源的遗传多样性分析将为此类资源的收集保存及应用提供依据。     

利用SSR标记分析藜麦品种的遗传多样性

为了解藜麦种质资源的多样性,本研究利用SSR引物对所搜集的41个藜麦种质的多态性及其亲缘关系进行了分析。结果表明,从54对SSR引物中筛选出了16对能明显扩增出稳定的多态性条带的引物,共检测出139个等位基因条带,每一对引物的等位基因个数为3~13,平均为8.7;16对引物的多态信息含量(PIC)变幅为0.208~0.432,平均为0.366。UPGMA聚类分析显示,41份材料的遗传相似系数(GS)在0.374~0.906之间,平均相似系数为0.626。在阀值(GS)约为0.665时,41份材料可分为4大类。其中614929与B.B.Quinoa浙Ⅰ间的遗传相似系数最小,为0.374,表明来源于不同地区的遗传距离较远,遗传基础较广泛。藜麦品种资源间的亲缘关系的揭示为藜麦资源保存和新品种选育提供了理论依据。     

基于SSR标记的梨资源遗传多样性分析

本研究利用SSR标记技术对56份梨资源进行了遗传多样性分析。利用筛选出的6对SSR引物共扩增40条谱带,其中多态性位点38个,多态性位点比例为95%,每对引物产生有效等位基因6.3个。各位点期望杂合度H值在0.0354～0.491,平均为0.1964;有效等位基因Ne值在1.0367～1.9648,平均值为1.2958;香农指数I值平均值为0.3256,说明了供试梨材料的遗传多样性较低。利用SSR标记可将44个栽培品种区分开,但无法区分芽变和原种。根据SSR标记揭示的多态性,采用NTSYS-pc软件,以UPGMA法进行聚类分析,结果显示所检测的56份梨材料在相似系数0.71处可分为4组,其中中国的白梨、秋子梨和砂梨相互交错在一起,没有独自各自成组。     

小麦杂种优势群研究III普通小麦和斯卑尔脱小麦微卫星分子标记遗传差异的研究

选用１５份我国不同生态区的普通小麦品种（系）及９份不同国家的斯尔脱小麦品种（系）,利用微卫星分子标记对小麦种间,品种（系）间遗传差异进行了研究,探讨扩大杂交小麦育种亲本遗传基础的途径。所利用的１８对微卫星引物的２４份材料中均有搁增产物,共扩增出分子量小于５００ｂｐ的条带４９５条,其中４６８条带（占９６．７８％）具有多态性,平均每个引物可拉增出２６．６条多态性带。研究发现,９份斯卑尔脱小麦微卫星多态     

Genealogical Analysis of Diversity of Russian Winter Wheat Cultivars (Triticum aestivum L.)

With the aid of genealogical analysis the genetic diversity of Russian winter Triticum aestivum L. wheat cultivars was studied. The change of diversity in time from 1929 to 2002 shows an increase in diversity of Russian cultivars due to the use of foreign material in the breeding programs. At the same time, the genetic erosion of the released diversity occurred. In the 1950s and the 1960s about 50% of the Russian local and old varieties had dropped out of the pool of landrace ancestors. The set of the modern cultivars included in the Russian Official List 2002 has a cluster structure. The overwhelming majority (96%) are the descendants of cultivars Bezostaya 1 and/or Mironovskaya 808. The low diversity of cultivars recommended for cultivation in the Central and Volga-Vyatka regions is apparent. This situation can result in losses of a yield due to a uniform susceptibility to pathogens.     

Evaluation of Genetic Diversity Among Bulgarian Winter Wheat (Triticum aestivum L.) Varieties During the Period 1925–2003 Using Microsatellites

Simple sequence repeats (SSRs) were used to study the genetic diversity within old and modern Bulgarian winter wheat (Triticum aestivum L.) varieties released in 20th century. A set of 91 varieties were screened by 19 wheat microsatellite markers (WMS), covering 17 wheat chromosomes, and one secalin-specific marker for rye chromosome arm 1RS. A total of 136 allelic variants were detected at 22 loci, ranging from 2 to 11, with an average of 6.8 alleles per marker. For 7 markers, null alleles were detected. The occurrence of rare alleles (frequency <2%) was observed for 13 markers. The polymorphism information content (PIC) values of the markers ranged from 0.10 (WMS0165 on 4AS) to 0.81 (WMS0437 on 7DL) with an average of 0.51. Approximately 74% of the varieties, mostly non-commercial, showed heterogeneity, with an average level of 10.1%. For the majority of markers, the relative frequencies of alleles varied considerably among different groups of varieties, revealing the effects of different selection between breeding centres. Some alleles, present in old genotypes, were lost, and new alleles have been introduced into modern varieties. Genetic diversity values over different periods of release were high, starting at 0.64 for varieties developed before 1960 to reach 0.71 in 1990s, revealing no declining trends in the diversity due to breeding activity. The cluster analysis discriminated all varieties (except for two) and revealed distinct groups of old and modern varieties, released from the main breeding centres in Northern, Southern and Western Bulgaria.     

Genetic analysis of wheat (Triticum aestivum L.) and related species with SSR markers

Genetic diversity among 19 Triticum aestivum accessions and 73 accessions of closely related species was analyzed using simple sequence repeat (SSR) markers. Forty-four out of 497 SSR markers were polymorphic. In total 274 alleles were detected (mean 6.32 alleles per locus). The polymorphic information content (PIC) of the loci ranged from 0.3589 to 0.8854 (mean 0.7538). The D genome contained the highest mean number of alleles (6.32) followed by the A and B genomes (6.13 and 5.94, respectively). The correlation between PIC and allele number was significant in all genome groups (0.7540, 0.7361 and 0.7482 for A, B and D genomes, respectively). Among the seven homologous chromosome groups, genetic diversity was lowest in group 7 and highest in group 5. In cluster and principal component analyses, all accessions grouped according to their genomes were consistent with their taxonomic classification. Accessions with the A and D genomes were clustered into two distinct groups, and AABB accessions showed abundant genetic diversity and a close relationship. Triticum durum and T. turgidum were clustered together, consistent with their morphological similarity. Cluster analysis indicated emmer is closely related to hexaploid wheat. Compared with common wheat, higher genetic variation was detected in spelt, T. aestivum subsp. yunnanense and subsp. tibetanum. In addition, a close genetic relationship between T. polonicum and T. macha was observed. The results of the clustering and principal component analyses were essentially consistent, but the latter method more explicitly displayed the relationships among wheat and closely related species.     

抗麦长管蚜小麦的遗传多样性及SSR标记与麦长管蚜抗性的关联分析

麦长管蚜(Sitobion avenae)是影响中国小麦(Triticum aestivum)生产的主要害虫之一。本研究选用99个简单重复序列(simple sequence repeat,SSR)标记对54份苗期和成株期麦长管蚜抗性一致的小麦品种进行聚类分析和麦长管蚜抗性关联分析。结果表明,99个SSR标记共鉴定出1 038个等位变异,平均每个位点的等位变异数为10.48个,变异数目在2~30个之间;SSR标记位点的多态性信息含量(PIC)的变异范围为0.178 6~0.973 8,平均为0.717 8。聚类分析表明,54份小麦品种聚成2大类群,大部分地理来源相近或麦长管蚜抗性相似的材料聚于同一亚类群。通过一般线性模型(general linear model,GLM)和混合线性模型(mixed linear model,MLM)两种关联分析模型,分别获得16个和4个麦长管蚜抗性相关联的标记,这些标记分别位于11条染色体的14个染色体臂上,GLM分析中各标记对表型变异解释率为0.221 9~0.556 7,MLM分析中各标记对表型变异解释率为0.029 5~0.063 3。研究结果为小麦抗麦长管蚜杂交育种及分子标记辅助育种提供理论依据。     

小麦T型细胞质雄性不育恢复基因Rf1和f4的SSR标记分析

为进一步探讨小麦(Triticum aestivum L.)T型细胞质雄性不育(T-CMS)育性恢复的遗传机理,并为利用T型不育系选育强优势杂交小麦分子辅助育种提供理论与技术支撑,本研究以小麦ms(S)矮抗58/R113的F2代分离群体中的极端可育株和极端不育株分别建立恢复池和不育池,采用分布于小麦第一染色体群(染色体1A、1B和1D)及第六染色体群(染色体6A、6B和6D)上的196对SSR引物进行扩增筛选.结果表明,(1)位于1AS染色体上的3个SSR标记和位于6BS染色体上的4个SSR标记均在亲本和基因池间扩增出了稳定的多态性差异条带;(2)定位群体验证结果表明,恢复基因Rf1与1AS染色体上Xgwm136、Xgpw7062和Xgdm33标记的遗传距离分别为4.8、9.6和13.7 cM,3个标记与Rf1之间的顺序依次为Xgdm33、Xgwm136、f1、Xgpw7062; (3)恢复基因Rf4与6BS染色体上的Xgpw1079、Xgwm193、Xgpw7011和Xgwm508标记的遗传距离分别为3.4、6.8、13.7和21.5 cM,4个标记与Rf4之间的顺序依次为Xgpw 011、Xgpw1079、Rf4、Xgwm19和Xgwm508.研究还表明,T-CMS恢复系R113的育性是由Rf1和f4两对主效恢复基因和多对微效基因共同控制的,筛选的上述7个SSR标记可直接用于T型或者类似T型,如S型杂交小麦分子标记辅助育种,可有效提高对应恢复系的选择效率.     

Root Plasticity Not Evident in N-Enriched Soil Volumes for Wheat (Triticum aestivum L.) and Barley (Hordeum vulgare L.) Varieties

Root plasticity is a unique characteristic of root systems that may enhance the nutrient foraging capacity of plants. Here we investigated the effect of localized high nitrogen (N) concentration on plasticity of wheat and barley roots in soil. We conducted a series of experiments to maintain localized high concentration of N in soil and to evaluate any root morphological variation in the enriched N zone. Wheat and barley seedlings were grown in N responsive Red Ferrosol with an enriched subsurface N band for 12 days. Wheat and barley roots did not proliferate in N-enriched soil volumes. Rather, higher root length density (~1.6 times) was observed in low N surface soil. Shoot dry matter and shoot N uptake of banded N treatment was statistically similar between uniform and low N treatments. Results indicated the absence of plastic root response of the wheat and barley seedlings in subsurface N band.     

Lox基因RNAi转基因小麦后代株系种子耐储藏性分析

小麦(Triticum aestivum)种子中脂氧合酶(lipoxygenase,LOX)可催化不饱和脂肪酸的氧化作用,在种子储藏期间产生氢过氧化物,导致小麦种子在储藏过程中种子活力和营养品质降低.因此,选育种子LOX活性低的小麦品种是小麦遗传改良的任务之一.为了获得种子脂氧合酶活性显著降低、外源Lox RNAi构件(Lox geneRNAiconstruct,Loxi)能稳定遗传且种子耐储藏性增强的转基因小麦新种质,本研究以小麦西农889、闫麦8911和陕优225转Loxi稳定遗传的TF7代转基因株系为材料,对转基因种子中Lox基因家族进行了半定量RT-PCR分析,结果表明,外源Loxi可有效抑制小麦籽粒中小麦脂氧合酶1(Triticum aestivum lipoxygenase Ⅰ,TaLox1)基因的表达,但小麦脂氧合酶2(Triticum aestivum lipoxygenase 2,TaLox2)和小麦脂氧合酶3(Triticum aestivum lipoxygenase 3,TaLox3)基因的表达量不变;对3个亲本及16个TF7代转基因株系的种子脂氧合酶活性检测,结果显示,与其亲本相比,转基因株系种子脂氧合酶活性显著降低;对人工加速老化处理7和14 d的转基因和对照种子分析发现,随着老化天数的增加种子活力降低,但转基因株系种子活力均显著高于其亲本材料;人工加速老化后脂肪酸组分和含量测定分析表明,转基因株系脂肪酸比其亲本材料氧化损失少.以上结果说明,转基因株系中Lox基因的RNAi可有效抑制其种子LOX活性,使转基因小麦后代种子耐储藏性增强;筛选鉴定得到的种子LOX活性显著降低且耐储藏性增强的转基因小麦株系可为小麦育种提供新的材料.     

Functional Characteristics of Bread Wheat (Triticum aestivum L.) Near‐Isogenic Lines Differing at the Waxy (Wx) Locus

The Waxy (Wx) gene in hexaploid wheat (Triticum aestivum L.) encodes granule‐bound starch synthase (GBSS1), which is involved in the synthesis of amylose, a mostly linear glucan polymer that makes up ∼25% of wheat starch. A null mutation of the Wx gene in each of the three genomes is associated with starch almost entirely consisting of the branched glucan polymer amylopectin (waxy starch), with corresponding changes in functionality. However, the rheological behavior of partially waxy starch remains unclear. The objective of this study was to characterize flour and baking quality in 16 near‐isogenic lines, null at the Wx locus on zero, one, two, or all three genomes, grown in four different environments. Across allelic groups, significant variations in amylose concentrations, flour paste viscosity, loaf structure and texture, dough stability, and proximate variables were observed. Because waxy wheat starch has greater water absorbance and resistance to retrogradation than normal starch, its inclusion in flour blends has been suggested as a means of improving the texture and appearance of bakery products and noodles. The results indicate that wheat encoding <3 functional homeologs of GBSS1 produces starch that has potential in the production of certain food items, such as Asian noodles. However, further research is necessary to determine the optimal amylose‐to‐amylopectin ratio to improve baking quality.