Assessment of genetic diversity among Chinese upland cottons with Fusarium and/or Verticillium wilts resistance by AFLP and SSR markers

Genetic diversity among 95 Chinese upland cottons with Fusarium and/or Verticillium wilts resistance was estimated using Amplified Fragment Length Polymorphism (AFLP) and Simple Sequence Repeat (SSR) markers. Twenty EcoRI-MseI AFLP and 19 SSR primers with polymorphism were selected to perform the fingerprinting. The results showed that 20 AFLP primer pairs produced a total of 1 480 major bands among 95 genotypes, and 214 were polymorphic bands. The number of total bands per primer pair ranged from 47 to 109, with an average of 74.0. The polymorphism information content (PIC) values for the 20 primer pairs varied from 0.01 (E-ACT/M-CAT) to 0.24 (E-ACA/M-CTA), and the average value was 0.09. Nineteen SSR primers generated 89 DNA bands, of which 61 were polymorphic. The total number of alleles per locus varied from 3 to 8, with an average of 4.7. The average PIC value for the SSR amplification products was 0.69. Genetic similarity estimates for the entire data set ranged from 0.978 to 0.998 based on AFLP and SSR bands. It was proved that the close genetic relationship and narrow genetic diversity existed in the tested cultivars. The clustering patterns could not be correlated to the geographic origin, the pedigree and common parentage of the cultivars.     

香稻品种遗传多样性研究

利用SSR分子标记分析78份外引香稻品种、18份在广西种植的香稻品种以及24份具有代表性的非香的广西地方栽培稻种质资源的遗传多样性,检测到100条多态性片段,每个引物可检测到3~14个多态性片段,平均为6.25个。聚类结果表明:利用16个SSR标记可以明显地把香稻与非香稻品种聚类为2大类;在78份外引香稻种质中,在遗传距离分别为0.64和0.56处,43份和14份各自聚为一类,占73.1%,18份与广西种植的香稻品种聚类,占23.1%,3份与非香的栽培稻品种聚为一类,占3.8%。不同类组香稻的Nei’s遗传距离估算表明,传统的南亚香稻的遗传多样性显著大于改良的南亚香稻,改良的南亚香稻的多样性又显著大于广西当前种植的香稻种质和广西代表性的非香稻种质。     

广西和广东优质常规稻的SSR遗传多样性分析

为探讨广西、广东近年育成的优质常规稻品种（系）的遗传多样性,以均匀分布在水稻基因组上的16对SSR多态性引物对101份优质常规稻进行遗传多样性分析。结果表明,16对引物均表现出多态性,共检测出55个多态性位点,平均等位基因Ap为3．4375,有效等位基因数Ae为2．0492,平均多态信息含量PIC为0．4760;聚类分析结果表明,不同水稻品种（系）间遗传相似系数变幅为0．6802～0．9798,说明SSR标记能够揭示不同材料间较高的遗传多样性,将101份水稻品种（系）完全区分开,为两广地区水稻品种资源的研究利用提供理论依据。     

利用SSR标记进行粳稻品种的遗传多样性研究

水稻育成品种遗传基础的宽窄及品种间遗传距离的大小是品种能否在当地有效推广种植的关键因素。为了扩大水稻杂交育种中亲本的选择,选用分布于水稻基因组的12条染色体上的30对SSR引物,对国内外的18个粳稻品种进行遗传多样性研究。结果显示,选取的30对SSR引物有28对具有多态性,多态性位点百分率为93%。这些多态性引物在18个材料中共扩增出144条多态性条带,平均每对SSR引物可检测到2~8个等位基因,平均5.14/位点。Nei遗传距离及系统聚类和带型分析结果表明,利用SSR标记可将18份材料分为4个类群,同一生态型的稻种基本聚为一类,部分不同生态型的稻种聚在一起,说明这几个品种之间有了一定的基因交流,具有相对较近的亲缘关系。育种亲本的选择不能单单考虑生态型。     

普通野生稻遗传多样性分析

为了扩大水稻杂交育种中亲本的选择、改变目前遗传基础狭窄的状况,试验选用分布于水稻基因组的12条染色体上的30对SSR引物,对国内外的20份普通野生稻进行遗传多样性研究。结果显示,试验选取的30对SSR引物均具有多态性,多态性位点百分率为100%;这些多态性引物在20份材料中共扩增出220条多态性带,平均每对SSR引物可检测到3～11个等位基因,平均每个位点7.3条。Nei遗传距离及系统聚类和带型分析结果表明,在Nei遗传距离为1.3处可将20份材料分为3个类群,即2个国外群体和1个国内群体;同一生态型的稻种基本聚为一类,个别不同生态型的稻种由于品种间的基因交流,具有相对较近的亲缘关系。说明SSR是一种进行遗传多样性研究切实有效的方法;育种亲本的选择不能仅仅依据生态型。     

广西非香地方栽培稻与香稻的遗传多样性比较

利用分布于水稻12条染色体上的16对SSR引物,分析24份广西非香地方栽培稻资源和18份广西种植香稻的SSR等位变异、多态信息含量、基因多样性等。结果表明,在广西非香地方栽培稻资源中,每对引物检测到的等位基因数为2~7个,平均每个位点的等位基因数为4.38个,平均多态信息含量(PIC)和平均基因多样性(Hs)分别为0.53和0.60;而在广西种植香稻资源中,每对引物检测到等位基因数2~9个,平均每个位点的等位基因数为3.44个,平均多态信息含量(PIC)和平均基因多样性(Hs)为0.41和0.47。说明广西非香地方栽培稻资源比香稻资源具有更为丰富的遗传多样性。聚类结果表明,广西非香地方栽培稻和香稻资源各自聚为一类,说明二者存在较大的遗传差异。     

尖镰孢EST-SSR信息分析及分子标记建立

【目的】探讨尖镰孢（Fusarium oxysporum）表达序列标签（expressed sequence tag,EST）序列中简单重复序列（simple sequence repeat,SSR）位点的分布特点,开发尖镰孢EST-SSR引物,为镰孢菌遗传多样性分析提供技术支持。【方法】从NCBI公共数据库下载尖镰孢EST 9 304条,利用SSRIT软件查找SSR位点,Primer Premier 5.0软件设计EST-SSR引物,用非变性聚丙烯酰胺凝胶（PAGE）电泳分离SSR-PCR扩增产物,并选用能够扩增出与预期产物大小一致且具有多态性的引物,对23株尖镰孢菌株进行SSR遗传多样性分析。【结果】在尖镰孢EST序列中,共搜索到92个SSR位点,分布于90条EST序列中,出现频率为1.0%。其中二核苷酸重复类型是最主要的SSR类型,占总SSR的比例为59.78%。其次为三核苷酸与五核苷酸重复类型,占总SSR的比例分别为17.39%、11.96%。出现频率最高的基序是（AC/GT）（0.51%）。设计合成的30对引物中有20对（66.7%）能够有效扩增,其中14对引物（46.7%）能够扩增出与预期产物大小一致且具有多态性的产物。尖镰孢的遗传多样性分析结果表明,利用筛选出的14对引物扩增出62条条带,其中多态性条带59条,多态性位点比例为95.2%,平均每对引物可扩增4.2条。供试菌株间的遗传相似系数为0.487-0.933,平均为0.686。供试菌株间存在明显的遗传分化。聚类分析结果表明,当遗传相似系数为0.781时,除14号菌株外,所有菌株均根据寄主来源划分为不同的SSR类群。【结论】基于尖镰孢EST序列开发SSR标记是一种简便有效的方法,研究开发的14对引物可用于尖镰孢的遗传多样性分析。     

花生优异种质的分子标记与遗传多样性分析

【目的】通过对花生遗传多样性的研究,为花生育种提供理论依据。【方法】运用ISSR和SRAP2种标记对24份重要花生种质资源的遗传多样性进行分析。【结果】32条ISSR引物中的13条引物共扩增出390条条带,其中多态性条带有293条,75.13%的条带可以揭示材料之间的遗传差异;252对SRAP引物中有229对引物为有效引物,共扩增出5827条可读的条带,其中多态性条带为3966条,平均每对引物可扩增17.32条条带。利用2种分子标记计算的相似系数的变化范围为0.60—0.80,将24份种质按系统聚类分析可以分为7组,按主坐标分析可以分为8组,从分子水平上解释了这些种质资源的遗传多样性水平和亲缘关系。【结论】ISSR和SRAP是非常有效、稳定和可靠的分子标记,可为花生育种的亲本利用及遗传连锁图的构建提供重要的科学依据。     

微卫星标记对籼稻品种遗传多样性分析

从水稻全基因组12条染色体上的439对SSR引物中选取30对,对国内外的12个籼稻品种进行遗传多样性研究。结果显示,试验选取的30对SSR引物中有29对具有多态性,多态性位点百分率为96.7%。这些多态性引物在12个材料中共扩增出137条多态性条带,平均每对SSR引物可检测到2～8个等位基因,平均4.7/位点。等位基因有效数(Ae)变幅为1～5.539,平均为3.47。多样性指数中,香浓多样性指数(I)为0～0.819,平均0.651;而Nei基因多样性指数变幅为0～1.907,平均1.3。Nei遗传距离及系统聚类和带型分析结果表明,利用SSR标记可将12份材料分为2个类群,国内和国外两个群体。说明SSR标记在区分水稻品种的生态型及遗传多样性研究方面具有重要作用,进一步证实了SSR标记是研究水稻种质资源分类、地理分布、生态类型的有效手段     

利用SSR标记划分微胚乳超高油玉米的杂种优势群

利用SSR分子标记研究了50份微胚乳超高油玉米自交系的遗传变异。从64对SSR引物中,选出扩增带型稳定的58对引物进行遗传多样性分析,共检测出207个多态性条带,涉及58个SSR位点,平均每个位点检测到的等位基因变异数为3.569个,变化范围2~7个;平均PIC值为0.560,变化范围从0.232到0.784。经遗传多样性和聚类分析把供试微胚乳超高油玉米自交系划分为4个类群(8个亚群)。聚类后的群内遗传相似系数大于群间遗传相似系数,这表明所选取的SSR引物可以有效地区分微胚乳超高油玉米自交系的遗传多样性,划分结果是客观合理的。     

山东核桃主要分布区种质资源遗传多样性AFLP分析

利用AFLP技术对山东省核桃主要分布区收集的55份核桃材料进行遗传多样性分析。结果表明,9对AFLP引物共扩增出566条谱带,其中440条为多态性条带,占总条带数的77.82%。聚类分析表明,材料间的遗传相似系数变幅为0.67～0.86;位点多态性信息含量(PIC)变幅为0.705～0.904,平均值为0.786;在遗传相似系数0.738水平上,55份核桃种质资源可聚成3大类。AFLP标记揭示出该55份核桃各群体之间存在较大遗传变异,各地区群体内遗传相似系数较高。     

Genetic diversity of Ustilago hordei in Tibetan areas as revealed by RAPD and SSR

Covered smut, which is caused by Ustilago hordei(Pers.) Lagerh., is one of the most damaging diseases of highland barley(Hordeum vulgare Linn. var. nudum Hook. f) in Tibetan areas of China. To understand the molecular diversity of U. hordei, a total of 27 isolates, which were collected from highland barley plants from Tibet, Sichuan, Qinghai, and Gansu provinces/autonomous region, were analyzed using random amplified polymorphic DNA(RAPD) and simple sequence repeat(SSR) markers. Among the 100 RAPD primers used, 24 primers exhibited polymorphism. A total of 111 fragments were amplified, of which 103 were polymorphic with a polymorphic rate of 92.79%. The average observed number of alleles(Na), effective number of alleles(Ne), Nei's genetic diversity(H), Shannon's information index(I) and polymorphism information content(PIC) value in the RAPD markers were 1.9279, 1.5016, 0.2974, 0.4503 and 0.6428, respectively. For the SSR markers, 40 of the 111 primer pairs exhibited polymorphism and provided a total of 119 bands, of which 109 were polymorphic and accounted for 91.60% of the total bands. The Na, Ne, H, I and PIC values of the SSR markers were 1.9160, 1.4639, 0.2757, 0.4211 and 0.4340, respectively. The similarity coefficients ranged from 0.4957 to 0.9261 with an average of 0.7028 among all the 27 isolates used. The dendrogram, which was developed based on the RAPD and SSR combined marker dataset showed that the 27 U. hordei isolates were divided into 3 clusters at similarity coefficient of 0.7314. We determined that RAPD and SSR markers can be successfully used to assess the genetic variation among U. hordei isolates. The RAPD markers revealed higher levels of genetic polymorphism than did the SSR markers in this study. There existed a moderate genetic difference among isolates. The molecular variation and differentiation was somewhat associated with geographical origin but not for all of the isolates.     

Assessment of the Genetic Diversity of Pummelo Germplasms Using AFLP and SSR Markers

The genetic diversities of 110 pummelo germplasms and 12 of their relatives were analyzed by SSR and AFLP methods. Approximately 99.1% of the 335 SSR loci were polymorphic, and 9.85 alleles per SSR locus were identified. The gene diversity values changed from 0.1939 to 0.9073, and 46 SSR polymorphic bands were scored. 72% of the 343 AFLP loci were polymorphic, and 82 polymorphic loci per AFLP were identified. Heterozygosity changed from 0.21863 to 0.28445, and 44 AFLP polymorphic bands were scored. The UPGMA result showed that 122 pummelo genotypes and their relatives could be divided into eight groups, and the pummelo genotypes composed mainly of Shatian pummelo varieties group, Wendan pummelo vareties group and a huge hybrid pummelo varieties group. The classification result was expected to widen the genetic background of pummelos using various target varieties.     

陕西省水稻种质资源的遗传多样性分析和指纹图谱构建

对陕西省40份大田推广品种及其亲本和100份省水稻区域试验材料进行遗传多样性分析。结果表明,从陕西省40份大田推广品种及其亲本共检测到160个等位基因,平均每个标记检测到6个等位基因,每个SSR位点的遗传多态性信息含量为0.29～0.97,平均为0.64。聚类分析表明,40份大田推广品种及其亲本的遗传相似系数为0.55～0.97。100份陕西省水稻区域试验材料中,72个晚熟水稻材料的遗传相似系数为0.43～0.91,平均为0.67。28个中早熟水稻材料的遗传相似系数为0.56～0.87。     

油茶AFLP反应体系建立及其在遗传多样性研究上的应用

通过试验分析建立了适合油茶且简便易行的AFLP反应体系,筛选出了4对能够反映多态性的有效引物,并对油茶的遗传多样性进行了初步分析。平均每对引物扩增出23个具有清晰条带的位点,其中多态性位点数N为18,多态性位点百分率PPL为79.13%,有效等位基因数ne为1.320,Nei’s期望杂合度He为0.184,Shannon多态性信息指数I为0.267。研究结果表明了AFLP标记技术在油茶遗传多样性研究上的适用性,同时也显示了油茶具有较高的遗传多样性,为进一步研究油茶多居群的遗传多样性奠定了重要的理论和技术支持。     

柚类种质资源AFLP与SSR遗传多样性分析

 结合SSR引物和AFLP分子标记对110份柚类基因型、12份野生近缘种进行遗传多样性研究。结果表明，SSR标记的335个位点中99.1%为多态性位点，每个位点可检测到9.85个等位基因，基因多样度 （GD）变幅为0.1939～0.9073，获得了46个特异性SSR标记；AFLP标记的343个位点中72%为多态性位点，3对引物平均期望杂合度变幅为0.21863～0.28445,平均每对引物组合能产生82个多态位点，获得了44个AFLP特异性标记。UPGMA聚类结果显示，122份基因型在相似系数0.61时，分成8个组群，其中柚类主要由沙田柚品种群、文旦品种群与庞大的杂种柚品种群组成。分类结果将有利于更好地利用这些丰富的育种资源。     

Assessment of genetic diversity in glandless cotton germplasm resources by using agronomic traits and molecular markers

Seventy-one glandless cotton germplasm resources were firstly evaluated genetically by using nine agronomic traits, 33 simple sequence repeat (SSR) primers and ten amplified fragment length polymorphism (AFLP) primer combinations. Principal component analysis (PCA) of the agronomic traits showed that the first six principal components (PCs) explained a total of 86.352% of the phenotypic variation. A total of 329 alleles were amplified for 33 SSR primers, and 232 polymorphic bands in a total of 389 bands were obtained by using ten AFLP primer combinations. The average polymorphic information content (PIC) value was 0.80 and 0.18 for SSR primers and AFLP primer combinations, respectively. The DIST (average taxonomic distance) and DICE (Nei and Li’s pairwise distance) coefficients ranged from 0.373 to 3.164 and 0.786 to 0.948, respectively, for agronomic traits and SSR&AFLP data based on UPGMA analysis. This suggested that there was a higher diversity in the evaluated population for both agronomic traits and molecular markers. The Mantel’s test showed that the correlation between the dendrograms based on agronomic traits and SSR&AFLP data was non-significant.     

基于SSR标记的福建省若干水稻品种DNA指纹图谱构建及遗传多样性分析

以24份杂交稻品种和18份杂交稻亲本为材料,利用SSR分子标记进行DNA指纹图谱构建和遗传多样性分析。24对引物在研究材料中共检测到74个多态性片段,平均每对引物的多态性片段为3.1个。基于24个SSR标记的扩增结果,利用NTSYS 2.10e软件计算Dice遗传相似系数,并建立UPGMA聚类图,结果表明:42份材料之间的相似系数变化范围为0.60~1.00,在遗传相似系数0.68处可以将42份材料分为6个类群,较好地反映了供试材料的亲缘关系,可为水稻育种中亲本选择提供参考。同时建立了42份材料×12个SSR标记的指纹图谱,为杂交水稻品种纯度和真伪鉴定提供科学数据。     

吉林省龙井保护区野生大豆居群遗传多样性的研究

利用28对SSR引物对吉林省龙井保护区一个居群的32份野生大豆进行了遗传多样性分析,共检测到120个等位变异,平均等位变异数为4.29个。32份野生大豆的遗传相似系数为0.58～1.0,平均相似系数为0.63。聚类分析结果表明,此居群野生大豆的生长趋势与地理位置有明显的相关性,呈遗传斑块生长。28对SSR引物得到的Simpson指数分布范围为0.119 1～0.673 8,平均值为0.454 4;Shannon-weaver指数分布范围为0.277 1～1.478 3,平均值为0.8865。通过遗传多样性指数表明:吉林省龙井保护区此居群的野生大豆具有较高的遗传多样性。     

Development of a Highly Informative Microsatellite （SSR） Marker Framework for Rice （Oryza sativa L.） Genotyping

To select highly informative microsatellite markers （SSRs） and establish a useful genetic SSR framework for rice genotyping, 15 rice （Oryza sativa L.） cultivars including six indica varieties and nine japonica varieties were used to analyze the polymorphism information content （PIC） value of 489 SSR markers. A total of 1 296 alleles were detected by 405 polymorphic markers with an average of 3.2 per locus. The PIC value of each chromosome was ranged from 0.4039 （chromosome 2） to 0.5840 （chromosome 11）. Among the two rice subspecies, indica （0.3685-0.4952） gave a higher PIC value than japonica （0.1326-0.3164） and displayed a higher genetic diversity. Genetic diversity of indica was high on chromosome 12 （0.4952） and low on chromosome 8 （0.3685）, while that for japonica was high on chromosome 11 （0.3164） and low on chromosome 2 （0.1326）. A SSR framework including 141 highly informative markers for genotyping was selected from 199 SSR markers （PIC〉0.50）. Ninety-three SSR markers distributed on 12 chromosomes were found to be related to indica-japonica differentiation. Of these 93 pairs of SSR primers, 17 pairs were considered as core primers （all the japonica varieties have the same specific alleles, while the indica varieties have another specific alleles）, 48 pairs as the second classic primers （all the japonica or indica varieties have the same specific alleles, while the indica or japanica varieties have two or more other specific alleles ） and 28 pairs as the third classic primers （all the japonica and indica varieties have two or more alleles, but the specific alleles are different between japonica and indica）. Thirty-two SSR markers were selected to be highly informative and useful for genetic diversity analysis of japonica varieties. This work provides a lot of useful information of SSR markers for rice breeding programs, especially for genotyping, diversity analysis and genetic mapping.