河北省冬小麦品种SSR标记遗传多样性分析

利用79对多态性较高的SSR引物,对河北省1997-2007年间审定的冬小麦品种及国家小麦区试抗旱对照品种晋麦47和洛旱2号,共计87个冬小麦品种进行遗传多样性分析。79对SSR引物共检测出175个等位变异位点,每对引物可产生1~6条等位变异位点,平均2.215条。标记位点多态性信息含量(PIC)变幅为0.824~0.998,平均为0.941;有效等位基因数(Ne)变幅为1.644~20.333,平均4.708;香农指数(H’)变幅为0.148~1.102,平均为0.544,说明河北省冬小麦品种SSR遗传多样性较低。品种间遗传相似系数(GS)变幅为0.184~0.899,平均为0.418,其中河农826与石家庄8号间的遗传相似性最高,GS高达0.899,71-3与藁优9618间的遗传相似性最低,GS为0.184。不同育种单位培育的小麦品种平均遗传相似系数存在较大差异。UPGMA遗传相似性聚类表明,石家庄市小麦新品种新技术研究所培育的小麦品种与其他单位品种存在较大的遗传差异。     

河北区试小麦品种(系)DNA指纹图谱构建及遗传差异分析

采用42个SSR标记为2009-2013年河北省区域试验的70份小麦品种(系)构建DNA指纹图谱,进行遗传差异分析,为小麦品种改良和种质资源创新提供参考。结果表明,42个SSR标记在70份品种(系)中共检测到303个等位变异,单个SSR位点的平均等位变异为7.21个,PIC值平均0.69;基因多样性平均0.73,遗传相似系数变化范围为0.05-1.00,平均0.28;表明参加河北省区域试验的品种(系)间存在不同程度的遗传差异。聚类分析把70份品种(系)划分为4大类,6个亚类,表明同一育种单位或地区品种(系)遗传背景相近,应该加大外来小麦种质资源的引进和利用力度。     

小麦21条染色体RFLP作图位点遗传多样性分析

对来自世界11个国家的15个小麦品种(系)(Triticum aestivum L.AABBDD,2n = 42)472个RFLP位点的遗传多样性进行了检测,并进行了逐条染色体分析,结果发现:(ⅰ) 15个品种在各条染色体上的聚类各不相同.根据472个遗传位点遗传多样性数据,15个品种可聚类为4类,Synthetic,Hope, Timgalen各为一类,其余品种为一类,遗传距离远近恰与其所携带的小麦亲缘种染色体数目有关.(ⅱ)普通小麦遗传多样性非常贫乏,不同国家来源的品种相似系数高达0.8以上,多数品种间的大多数位点无遗传多样性,有53%的位点在供试的栽培品种中完全无多样性.(ⅲ)以四倍体小麦(AABB)和粗山羊草(DD)为亲本的品种(系)中,其对应的染色体上有较高的遗传多样性,其中有49.4%的等位变异在供试栽培种中没有发现,说明小麦的原始供体种是丰富现代栽培小麦遗传多样性的重要资源.(ⅳ) 根据遗传多样性位点及其作图位置, 可以检测到小麦栽培品种与其亲缘种杂交后代中亲缘种的染色体(片段).(ⅴ)在小麦的A,B,D3个基因组中, B基因组的遗传多样性最高,D基因组最差(尤以1D最甚),A基因组居中.(ⅵ)中国古老栽培品种中国春(CS)与国外栽培品种主要差异表现在染色体1B,3B和5A上,并发现了12个中国春的特异等位变异.认为现代栽培小麦遗传多样性狭窄是目前小麦育种难以取得突破的关键问题之一,并对如何丰富小麦的遗传多样性提出了建议.     

用SSR标记分析抗疫霉根腐病大豆品种(系)的遗传多样性

利用50对SSR引物对抗疫霉根腐病大豆品种(系)进行遗传多样性分析。在166份品种(系)中,50个SSR座位共产生265个等位变异,平均每个座位5.3个。采用NTSYS-pc2.10计算品种(系)间遗传相似系数,平均相似系数为0.3124,表明抗疫霉根腐病大豆品种(系)间的遗传差异较大。用UPMGA进行聚类分析,166个品种(系)在相似系数为0.33时被聚为6类,地理来源相同的品种(系)大多聚类在一起。一些具有相同或相近抗病反应型的品种(系)被聚类在同一个类群中,表明这些抗病品种(系)的遗传关系较近,应有选择地利用。W illiam s和C lark抗疫霉根腐病近等基因系构成明显不同于中国大豆的基因源,可以用于拓宽我国大豆品种的遗传基础。     

棉花耐盐相关种质资源遗传多样性分析

为了解我国棉花耐盐相关种质资源的遗传变异,利用88对SSR引物对23份棉花耐盐材料和24份盐敏感材料进行遗传多样性分析。88个SSR位点在47份材料中共检测出338个等位基因变异,平均每个位点有3.841个;其中耐盐材料中检测出333个,盐敏感材料中检测出312个。耐盐材料的位点多态信息含量(PIC)、每个位点的有效等位基因数(Ne)、基因型多样性(H′)分别为0.613、2.929和1.083,盐敏感材料的PIC、Ne、H′分别为0.605、2.883和1.071。耐盐材料和盐敏感材料的Jaccard相似性系数分别在0.530–0.979和0.525–0.878之间,遗传相似性系数总体平均值接近,但耐盐材料的变化幅度更大。用类平均法(UPGMA)聚类将47份材料分成3个类群。总体而言,大多数材料之间的遗传相似性系数较高,表明我国陆地棉耐盐相关种质资源遗传基础狭窄。本结果为棉花耐盐育种中亲本的选配和优势组合的预测以及耐盐资源的合理利用等提供了基础资料。     

湖北夏大豆种质 SSR 标记的遗传多样性研究

利用SSR标记和系统聚类分析,对92个湖北夏大豆种质进行遗传多样性分析。结果表明,28个SSR位点检测到134个等位变异,每个SSR位点的等位变异范围为2~9个,平均4.78个。鄂西南山区的遗传多样性指数和等位变异数最高,其次为江汉平原区。83.6%以上的遗传差异是由于地区差异引起,表现较高程度的地理分化。系统聚类将92个大豆品种分为3个类群,Ⅰ类和Ⅲ类分别以鄂西南山区品种和江汉平原区品种为主。鄂西南山区和江汉平原区的大豆地方品种表现遗传多样性水平较高。     

小麦大面积种植品种与骨干亲本的遗传差异解析

为了解小麦大面积种植品种和育种骨干亲本的遗传差异特点,利用分布于小麦全基因组的428个SSR标记对4个大面积种植品种和4个骨干亲本进行了比较分析。结果表明,8个材料间的遗传距离变异范围为0.460~1.126,平均0.876,其中骨干亲本间的平均遗传距离(0.955)高于大面积种植品种(0.718)。骨干亲本中检测到的等位变异数较大面积种植品种高16.4%,前者的平均等位变异(2.90)也略高于后者(2.43)。从不同基因组和染色体来看,骨干亲本在A、B和D基因组上及19对染色体(除了2D和6D)的平均等位变异均高于大面积种植品种。以上分析表明骨干亲本的遗传异质性高于大面积种植品种。进一步比较二者的分子差异,发现骨干亲本中有518个特有等位变异(在大面积品种中没有出现),其中Xwmc513和Xbarc59为骨干亲本共有位点,大面积品种中也检测到315个特有等位变异,其中Xp3029、Xwmc235、Xgwm518、Xgdm43、Xbarc146和Xcfd80为共有位点。前人研究表明骨干亲本的一些染色体区段传递给了大面积种植品种,在它们的形成中发挥了重要作用。本研究发现的特异位点可能是遗传研究中除了骨干亲本重要位点之外的一些需要重点关注的基因组区域,进一步研究有助于解析一个品种是被大面积推广利用或成为骨干亲本的形成原因。     

基于SRAP标记的甜瓜耐盐种质资源遗传多样性分析

研究不同耐盐程度甜瓜种质资源的亲缘关系和遗传多样性,为甜瓜种质资源有效利用提供理论依据。该试验以不同耐盐程度的27个甜瓜品种为材料,利用SRAP标记分析甜瓜种质资源的遗传多样性,从364对引物组合中筛选出24对扩增清楚且多态性丰富的引物,共扩增出415个清晰的位点,其中多态性位点241个,多态比率达58%。平均观测等位基因数(Na)为1.588 0,平均有效等位基因数(Ne)为1.347 0,平均Nei's基因多样性指数(H)为0.201 3,平均Shannon's信息指数(I)为0.301 0,表明供试甜瓜具有丰富的遗传多样性。UPGMA聚类结果显示:遗传相似系数在0.36～1.00之间,遗传相似性系数在0.72时,可将27个甜瓜品种划分为4个类群,耐盐型甜瓜在其中3个类群有分布,中等耐盐型甜瓜在4大类群中均有分布,盐敏感型均集中在第Ⅰ类群,表明耐盐型和中等耐盐型甜瓜种质的遗传多样性比盐敏感型种质丰富。遗传相似系数与UPGMA聚类结果的Cophentic矩阵相关系数为0.749,说明聚类分析结果较准确。研究认为,耐盐型甜瓜的遗传多样性较丰富,要得到耐盐的杂种优势品种,需要融入更多遗传关系较远的新种质。     

河北省大豆推广品种遗传多样性分析

利用主要农艺性状以及SSR和AFLP2种分子标记,对河北省41个大豆推广品种进行遗传多样性分析,以便为种质资源利用和创新提供依据。农艺性状聚类结果将41个材料划分为3个类群和2个特殊品种,聚类结果与材料系谱来源相差悬殊,不能反映材料间亲缘关系。SSR和AFLP数据聚类结果将41个材料划分为4个SAG（SSR and AFLP—basedgroups）分子类群。30对SSR引物共检测出135个等位变异,平均每个位点上有4．47个等位变异,SSR的遗传多样性指数（Simpson）分布范围为0．0928～0．7800,平均值为0、6442。10对AFLP引物共扩增出93个多态性标记,平均每对引物9．3个多态性标记。品种间的遗传相似系数（GS）变化范围为0．5877～0．9868,平均值变化范围为0．6732～0．7653,总体平均值为0.7237,遗传相似系数较高,说明材料间遗传变异较小。     

我国育成小麦品种的遗传多样性演变

对我国小麦育成品种初选核心种质(1680份)的78个微卫星标记(SSR)位点进行了扫描,并就此对50年来育成品种的遗传多样性进行了评价和分析,得到以下结果和结论:(ⅰ)74对SSR荧光引物共检测到1336个等位变异,其中1253个等位变异可以定位在71个位点上.这71个位点上检测到的每个位点等位变异数为4~44个,平均17.6个;多态性信息指数(PIC)为0.19~0.89,平均为0.69.(ⅱ)三个基因组的平均等位变异丰富度为B>A>D,遗传多样性指数为B>D>A.(ⅲ)7个部分同源群的平均等位变异丰富度为2=7>3>4>6>5>1,遗传多样性指数为7>3>2>4>6>5>1.结合两个指标分析,第7部分同源群具有最高的多样性,而1,5群多样性最低.(ⅳ)21条染色体中,7A,3B和2D三条染色体遗传多样性较高,而2A,1B,4D,5D和1D的遗传多样性偏低.(ⅴ)育成品种遗传多样性指数以50年代的最高,以后越来越低,但年代间变化较平缓;品种间平均遗传距离以50年代最高(0.731),以后逐渐减小,各年代依次为0.711,0.706,0.696和0.695.品种遗传基础狭窄化问题日趋突出,应引起有关部门和育种家的关注.     

Assessing genetic diversity of wheat (<Emphasis Type="Italic">Triticum aestivum</Emphasis> L.) germplasm using microsatellite markers

A set of 24 wheat microsatellite markers, representing at least one marker from each chromosome, was used for the assessment of genetic diversity in 998 accessions of hexaploid bread wheat (Triticum aestivum L.) which originated from 68 countries of five continents. A total of 470 alleles were detected with an average allele number of 18.1 per locus. The highest number of alleles per locus was detected in the B genome with 19.9, compared to 17.4 and 16.5 for genomes A and D, respectively. The lowest allele number per locus among the seven homoeologous groups was observed in group 4. Greater genetic variation exists in the non-centromeric regions than in the centromeric regions of chromosomes. Allele numbers increased with the repeat number of the microsatellites used and their relative distance from the centromere, and was not dependent on the motif of microsatellites. Gene diversity was correlated with the number of alleles. Gene diversity according to Nei for the 26 microsatellite loci varied from 0.43 to 0.94 with an average of 0.77, and was 0.78, 0.81 and 0.73 for three genomes A, B and D, respectively. Alleles for each locus were present in regular two or three base-pair steps, indicating that the genetic variation during the wheat evolution occurred step by step in a continuous manner. In most cases, allele frequencies showed a normal distribution. Comparative analysis of microsatellite diversity among the eight geographical regions revealed that the accessions from the Near East and the Middle East exhibited more genetic diversity than those from the other regions. Greater diversity was found in Southeast Europe than in North and Southwest Europe. The present study also indicates that microsatellite markers permit the fast and high throughput fingerprinting of large numbers of accessions from a germplasm collection in order to assess genetic diversity.     

An estimation of the minimum number of SSR loci needed to reveal genetic relationships in wheat varieties: Information from 96 random accessions with maximized genetic diversity

Genetic relationships among common wheat varieties from the 10 wheat growing regions of China were assessed using SSR markers. The wheat varieties included 33 modern varieties and 63 landraces selected from the national gene bank collection of China. One hundred and four pairs of selected primers detected a total of 802 alleles, of which 234 were specific to A genome, 309 to B genome, and 221 to D genome. The average genetic richness per locus (A _ij /loci) for A, B and D genomes were 6.88, 7.92 and 7.62, respectively. Their average genetic dispersion indices (H _t ) were 0.637, 0.694 and 0.656, respectively. The B genome showed the highest genetic diversity among the three wheat genomes. The landraces had a higher genetic diversity than the modern varieties, and the major difference between the landraces and the modern varieties in China existed in the D genome, followed by B and A genomes. The majority of the accessions (65.6%) had heterogeneity at the 112 loci detected. The highest heterogeneity locus percentages were 9.09 and 12.73 in the modern varieties and the landraces, respectively. SSR data were analyzed with NTSYS-pc software. The genetic similarities between accessions were estimated with the DICE coefficient. The accessions clustered into two groups, the modern varieties and the landraces by the un-weighted pair-group method using arithmetic average (UPGMA). The trend of correlation coefficients between genetic similarity matrices based on different numbers of random alleles and that of 802 alleles showed that 550 alleles were sufficient to construct a robust dendrogram. The separated simulations from six sub-samples revealed that 550 alleles were the minimum number required to confidently determine the genetic relationships. It was shown that the number of alleles (loci) needed do not have a strong association with the number of wheat lines in the sample size. These data suggested that 73 loci with good polymorphism are needed to reflect genetic relationships among accessions with more than 90% certainty. In the dendrogram, most accessions from the same wheat region were clustered together, and those from geographically adjacent regions usually appeared in the same small group. This indicated that genetic diversity of Chinese common wheat has a close association with their geographic distribution and ecological environment.     

黄淮麦区小麦品种(系)的ISSR位点遗传多样性分析

选用11个ISSR引物,对黄淮麦区96个小麦推广品种（系）进行遗传多样性分析。共检测到96个多态性位点,每个引物多态性位点数平均为8．7个,变幅为3～23个;ISSR引物的多态性信息含量PIC变幅为0．601～0．941,平均0．791,表明ISSR具有较强的品种间区分能力,是研究小麦种质资源遗传多样性的有效分子标记技术之一。96个品种（系）间,Nei’s遗传相似系数变化范围为0．53～0．91,平均为0．60,品种间遗传相似性变幅较大,表明黄淮麦区不同小麦品种（系）间存在着不同程度的遗传多样性差异。根据品种间遗传相似系数聚类,96份材料被聚成8大类群,共14个亚类,类群与系谱和原产地无关。     

Genetic Diversity, Population Structure and Linkage Disequilibrium in Elite Chinese Winter Wheat Investigated with SSR Markers

To ascertain genetic diversity, population structure and linkage disequilibrium (LD) among a representative collection of Chinese winter wheat cultivars and lines, 90 winter wheat accessions were analyzed with 269 SSR markers distributed throughout the wheat genome. A total of 1,358 alleles were detected, with 2 to 10 alleles per locus and a mean genetic richness of 5.05. The average genetic diversity index was 0.60, with values ranging from 0.05 to 0.86. Of the three genomes of wheat, ANOVA revealed that the B genome had the highest genetic diversity (0.63) and the D genome the lowest (0.56); significant differences were observed between these two genomes (P<0.01). The 90 Chinese winter wheat accessions could be divided into three subgroups based on STRUCTURE, UPGMA cluster and principal coordinate analyses. The population structure derived from STRUCTURE clustering was positively correlated to some extent with geographic eco-type. LD analysis revealed that there was a shorter LD decay distance in Chinese winter wheat compared with other wheat germplasm collections. The maximum LD decay distance, estimated by curvilinear regression, was 17.4 cM (r(2)>0.1), with a whole genome LD decay distance of approximately 2.2 cM (r(2)>0.1, P<0.001). Evidence from genetic diversity analyses suggest that wheat germplasm from other countries should be introduced into Chinese winter wheat and distant hybridization should be adopted to create new wheat germplasm with increased genetic diversity. The results of this study should provide valuable information for future association mapping using this Chinese winter wheat collection.     

新疆甜高粱种质资源遗传多样性的SSR分析

选用50对SSR引物对新疆现有72份甜高粱种质资源进行遗传多样性分析。结果表明:有20对引物在72份甜高粱种质资源中表现为多态性。共检测到91个等位基因,每对引物可检测到的等位基因数目为2～5个,平均为3.45个。多态性信息量(PIC)的变动范围为0.2859～0.6652,平均为0.5057。72份甜高粱种质间的遗传相似系数变化范围为0.2001～1.000,平均值为0.5599。UPGMA聚类分析将72份材料划分为A、B两大类群,A群包括69份材料,而A群又被分成从Ⅰ到Ⅺ共11个亚群,B群包括3份材料,农艺性状近似的大多被聚到同一类群。     

基于全基因组的河北省小麦品种遗传多样性分析

丰富的遗传变异对于提高作物的环境适应性和遗传改良进度至关重要。小麦是重要的粮食作物,河北省作为我国第三大小麦产区,在保障国家粮食安全中占有重要地位。建国以来,河北省审定了大量小麦品种,然而有关其遗传基础的研究却相对缺乏。本研究以1949年至2012年的169份河北省小麦品种为材料,利用覆盖小麦全基因组的SSR标记分析了供试小麦品种的遗传多样性。结果表明,供试河北省小麦品种的3个染色体组中,以B染色体组具有最高的遗传多样性,A组最低;7个同源群中,以第5、4群具有最高的多样性水平,而第7群最低;在21条染色体上的遗传多样性变化较大,以4A、2D具有较高的多样性水平,1A染色体最低。从品种的更新换代角度看,自1949年以来,尽管品种的等位基因频率在下降,河北省小麦品种的多样性水平基本呈现上升趋势。在此基础上,根据遗传相似系数,供试品种可聚为5大类,聚类结果既反映出河北省小麦品种多样性水平的复杂多样,也反映出品种的地域性分布特征。     

405份CIMMYT引进小麦种质的遗传多样性分析

为了明确国际玉米改良中心(CIMMYT)引进普通小麦种质材料的遗传多样性特点,为其利用提供参考依据,本研究从均匀分布于小麦基因组的420对SSR引物中选择出条带清晰、多态性较好的62对引物对引自CIMMYT的405份普通小麦种质系进行遗传多样性检测。结果表明,62对SSR引物在405份CIMMYT材料中共检测到198个等位变异,每对引物检测到等位变异的数目为2~8个,平均每对SSR引物能够检测到3.19个等位变异。单个SSR引物的PIC值介于0.03~0.79之间,平均值0.48。405份CIMMYT材料A、B、D基因组之间多态性位点数和等位变异数相差不大,PIC平均值B基因组(0.53)A基因组(0.52)D基因组(0.39)。聚类分析结果显示,62对SSR引物能够将405份CIMMYT材料区分开来,在0.1285遗传距离处将供试材料分为24个类群,类型较为丰富,不同类群的材料在农艺性状和品质性状上存在差异。     

Microsatellite analysis of Aegilops tauschii germplasm

The highly polymorphic diploid grass Aegilops tauschii isthe D-genome donor to hexaploid wheat and represents a potential source for bread wheat improvement. In the present study microsatellite markers were used for germplasm analysis and estimation of the genetic relationship between 113 accessions of Ae. tauschii from the gene bank collection at IPK, Gatersleben. Eighteen microsatellite markers, developed from Triticum aestivum and Ae. tauschii sequences, were selected for the analysis. All microsatellite markers showed a high level of polymorphism. The number of alleles per microsatellite marker varied from 11 to 25 and a total of 338 alleles were detected. The number of alleles per locus in cultivated bread wheat germplasm had previously been found to be significantly lower. The highest levels of genetic diversity for microsatellite markers were found in accessions from the Caucasian countries (Georgia, Armenia and the Daghestan region of Russia) and the lowest in accessions from the Central Asian countries (Uzbekistan and Turkmenistan). Genetic dissimilarity values between accessions were used to produce a dendrogram of the relationships among the accessions. The result showed that all of the accessions could be distinguished and clustered into two large groups in accordance with their subspecies taxonomic classification. The pattern of clustering of the Ae. tauschii accessions is according to their geographic distribution. The data suggest that a relatively small number of microsatellites can be used to estimate genetic diversity in the germplasm of Ae. tauschii and confirm the good suitability of microsatellite markers for the analysis of germplasm collections. Received: 8 September 1999 / Accepted: 7 October 1999     

Evaluation of Genetic Diversity in Chinese Wild Apple Species Along with Apple Cultivars Using SSR Markers

China, one of the primary centers of genetic diversity for the genus Malus, is very rich in wild apple germplasm. In this study, genetic diversity in 29 Malus accessions, including 12 accessions from 7 Chinese Malus species, 4 Chinese landraces, and 13 introduced apple cultivars, was assessed using a set of 19 single-locus simple sequence repeat (SSR) markers distributed across all 17 linkage groups of the apple genome. The number of alleles detected at each locus ranged from 2 to 11, with an average of 5.3 per SSR marker. In some accessions, 16 unique alleles were identified. Ten out of these 16 unique alleles (62.5%) were detected exclusively in wild species, indicating that these Chinese wild apple species have considerable genetic diversity and can be used in breeding programs to increase the genetic diversity of apple cultivars. Using 19 SSRs, an unweighted pair-group method with arithmetic average cluster analysis was conducted, and the resulting dendrogram revealed that all cultivars, except for E??peMeBckoe, were clustered together in the same group. The Russian cultivar E??peMeBckoe was closely related to the Chinese crabapple Baihaitang (M. prunifolia), with a high similarity coefficient value of 0.94. Of the two M. sieversii accessions used, one accession showed a close relationship to apple cultivars, while the other accession was closely related to wild apple species, suggesting the presence of a wider genetic diversity in Chinese M. sieversii species. The influence of SSR marker selection on genetic diversity analysis in this Malus collection was also discussed.     

Molecular characterization and genetic diversity analysis of soybean (Glycine max (L.) Merr.) germplasm accessions in India

Molecular characterization and genetic diversity among 82 soybean accessions was carried out by using 44 simple sequence repeat (SSR) markers. Of the 44 SSR markers used, 40 markers were found polymorphic among 82 soybean accessions. These 40 polymorphic markers produced a total of 119 alleles, of which five were unique alleles and four alleles were rare. The allele number for each SSR locus varied between two to four with an average of 2.97 alleles per marker. Polymorphic information content values of SSRs ranged from 0.101 to 0.742 with an average of 0.477. Jaccard’s similarity coefficient was employed to study the molecular diversity of 82 soybean accessions. The pairwise genetic similarity among 82 soybean accessions varied from 0.28 to 0.90. The dendrogram constructed based on genetic similarities among 82 soybean accessions identified three major clusters. The majority of genotypes including four improved cultivars were grouped in a single subcluster IIIa of cluster III, indicating high genetic resemblance among soybean germplasm collection in India.

Electronic supplementary material

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