云南椰子种质资源遗传多样性的ISSR分析

为摸清云南椰子种质资源遗传多样性现状,促进资源的有效利用,以在云南收集的60份椰子种质为试材,利用ISSR分子标记技术对其遗传多样性进行了分析。结果表明：27条ISSR引物共扩增出272个位点,其中230个为多态性位点,多态性比率为84.56%,引物多态性指数为0.85,SM遗传相似系数平均值为0.664。根据各种质的SM,运用NTSYSpc2.10e软件的UPGMA方法构建了种质的系统聚类图,60份椰子被聚为3个类群(A、B、C)。其中,A类群为全部由本地种质组成的一个独立类群;C类群既包括部分本地种质,也包括来源于本地以外的其他种质。研究结果显示出云南椰子种质具有较高的遗传多样性;这些种质与外地种质具有独立性和关联性的特点。该研究结果可为云南椰子种质资源的进一步研究和利用提供参考。     

Genetic diversity in mustard (Brassica juncea L.) germplasm from Pakistan as determined by RAPDs

The genetic diversity and the relationships among a collection of mustard (B. juncea) germplasm, including 41 accessions collected from Pakistan, 6 oilseed cultivars/ lines and 5 Japanese vegetable cultivars, were evaluated using random amplified polymorphic DNA (RAPD) markers. A total of 198 polymorphic amplified products were obtained from 30 decamer primers. Of these, 14 were unique to the accession PAK-85835 and 37 were specific to PAK-85839. Based on pair-wise comparisons of RAPD amplification products, genetic similarity was estimated using similarity coefficients of Nei & Li (1979) and a dendrogram was constructed using the unweighted pair-group method with arithmetic averages (UPGMA). Cluster analysis based on these genetic similarities placed most of the collected germplasm and oilseed cultivars/lines close to each other, showing a low level of polymorphism between the oilseed accessions collected in Pakistan. However, the clusters formed by the oilseed collections and cultivars were distinct from those formed by the vegetable cultivars. A low level of genetic variability of oilseed mustard in Pakistan was attributed to the selection for similar traits and horticultural uses. The farmers' preference for more remunerative crops and perhaps the close parentage of these accessions further contributed towards their little diversity. The study demonstrated that the RAPD is a simple and fast technique to compare the genetic relationships and the patterns of variation among accessions of this crop. This revised version was published online in August 2006 with corrections to the Cover Date.     

Random amplified polymorphic DNA variation among German and Dutch asparagus cultivars

DNA polymorphism among nine cultivars of Asparagus officinalis L. was measured using random amplified polymorphic DNA (RAPD). Of 69 reproducible amplification products from 12 arbitrary decamer primers, 49 RAPD markers were polymorphic and could be used to distinguish six German and three Dutch asparagus cultivars. Even with very small sample sizes, genetic similarity measurements based on the RAPD data allowed accurate grouping of the nine cultivars into distinct clusters, with the exception of two individuals which clustered to closely related varieties. Two German cultivars showed high genetic similarity and were distinct from the remaining German varieties. The German and Dutch cultivars were clearly separated by a relatively large genetic distance.     

利用ISSR标记研究鹅观草属种质资源的遗传多样性

为进一步了解鹅观草属种质资源的遗传背景和拓宽牧草育种的遗传基础,科学指导鹅观草属种质资源的收集、评价和利用,利用ISSR(Inter simple sequence repeat marker)标记对鹅观草属20个种,6个变种,共60份材料进行了遗传多样性检测。结果发现,被测材料间ISSR标记的多态性较高,在20个引物中,有16个引物可扩增出清晰且重复性好的DNA片段,共产生125条DNA片段,其中104条具有多态性,多态性比率为83.20%;每个引物可扩增出6～10条DNA片段,平均7.81条,材料间遗传相似系数GS变幅为0.188～0.879,平均值为0.375;聚类分析表明,在遗传相似系数为0.441的水平上,60份材料可以聚为5类,属于同种、同组、同系的不同材料首先聚在一起,然后再与其他种的材料聚在一起,此外,材料的聚类还表现出一定的地域性规律。     

越橘种质资源的CDDP遗传多样性及聚类分析

分析保守DNA序列多态性(CDDP)标记在蓝莓中的分布及其与生物性状之间的联系,为蓝莓种质的科学评价和合理开发提供理论指导及技术支持。通过筛选多态性丰富的CDDP引物,对32份蓝莓种质资源的基因组DNA进行扩增,根据统计结果分析品种的遗传多样性及聚类关系。共筛选出17条多态性高、产物清晰易辨的CDDP引物。32份样品共检测到207条带,其中多态性条带188条,比例为90.82%,特异条带17条,比例为8.21%。可以用2条引物组合完全区分32种蓝莓。在种群水平上,有效等位基因数、Nei’s基因多样性指数和Shannon信息指数分别为1.59、0.37和0.56。样本间的遗传相似系数范围在0.44~1.00之间,平均为0.73。在相似系数为0.69时,32个蓝莓种质分为3类,野生种笃斯越桔单独聚为一类,矮丛品种‘Blomidon’和半高丛品种‘Northblue’聚为一类,其他品种聚为一大类。CDDP标记在蓝莓中具有较高的多态性及特异性,与种质的需冷量、抗寒性及果实颜色具有一定的相关性。CDDP技术可有效用于蓝莓种质资源遗传多样性分析、品种鉴定及分子标记辅助育种。     

Genetic diversity within spelta and macha wheats based on RAPD analysis

Genetic diversity in a crop species is basic to improvement of the species and can be estimated at the molecular level. The objective of this study was to estimate genetic diversity within and between spelta and macha wheats. Random amplified polymorphic DNA (RAPD) analysis was conducted on 69 spelta and 32 macha wheat accessions. The classification of spelta and macha accessions, based on Jaccard genetic similarity coefficients for RAPD markers, was consistent with their geographic origin. The results indicated that the germplasm of macha wheat was more diverse than that of spelta wheat. In the dendrogram of macha wheat, four spelta-like accessions grouped together, separate from the remaining macha accessions, suggesting that these accessions were misclassified. In addition, accessions with identical RAPD patterns were found, indicating that these accessions were probably duplicated. Thus RAPD analysis can be used to estimate genetic diversity and identify duplicate accessions in wheat germplasm collections. This revised version was published online in August 2006 with corrections to the Cover Date.     

基于分子标记的野生棉遗传关系研究

利用RAPD技术研究了野生棉种间遗传关系。采用45条随机引物获得758个条带,根据UP GMA聚类分析将16个野生棉种分为5组。第1组包括B组染色体的4个棉种,其中异形棉(G.anomalum)与三叶棉(G.triphyllum)相似系数高达0.96。第2组包括瑟伯氏棉(G.thurberi)等7种,长萼棉(G.longicalyx)、比克氏棉(G.bickii)分别单独构成第4,5组,斯特提棉(G.sturtianum)、澳洲棉(G.australe)和细毛棉(G.pilosum)组成第3组。     

Molecular characterization of taro (Colocasia esculenta) using RAPD markers

Forty-four taro (Colocasia esculenta), two tanier (Xanthosoma species) and one Colocasia gigantea accessions were evaluated for genetic diversity using random amplified polymorphic DNA (RAPD) primers. Seventy-three of 112 primers amplified PCR DNA products used to fingerprint the accessions. Thirty-two primers were considered highly informative because they amplified more than 5 bands or amplified one or more polymorphic bands that distinguished between accessions. RAPDs showed high genetic diversity in taro accessions from Indonesia, were capable in distinguishing between Hawaiian accessions, and could separate triploid from diploid accessions. UPGMA cluster analysis of genetic similarity estimates (Jaccard's coefficient), separated the accessions into 3 main groups with C. esculenta divided into 5 subgroups. These primers will be useful for future genetic analysis and provide taro breeders with a genetic basis for selection of parents for crop improvement. Polymorphic markers identified in the DNA fingerprinting study will be useful to screen a segregating population which is being generated in our laboratory aimed at developing a taro genetic linkage map. This revised version was published online in July 2006 with corrections to the Cover Date.     

Correlation between morphological,chemical and RAPD markers for assessing genetic diversity in Withania somnifera (L.) Dunal

Genetic diversity among 14 Withania accessions were studied using morphological, chemical, and RAPD (Rapid Amplification of Polymorphic DNA) markers. On the basis of morphological variation and maximum assimilation of chemical constituents, wild accessions were considered elite as compared to cultivated. The molecular study showed that a total of 12 DNA fragments were amplified with five random decamer primers 75% of which were polymorphic. Genetic similarity matrix based on the Dice index detected coefficients ranging from 0.556 to 0.941. These coefficients were used to construct a dendrogram using unweighted pair group method with arithmetic mean (UPGMA). These accessions were clustered into two major groups; the first group included AGB-009, AGB-012, AGB-042, AGB-030, AGB-053, AGB-019, AGB-017, AGB-002, and AGB-003; the second included AGB-025, AGB-001, AGB-036, AGB-015, and AGB-055. The highest similarity among the Ashwagandha accessions was observed between AGB-009 and AGB-030, AGB-009 and AGB-012, AGB-042 and AGB-030, AGB-025 and AGB-001, AGB-036 and AGB-015, AGB-015 and AGB-055 and between AGB-015 and AGB-055. The most distant populations in the dendrogram were AGB-053 and AGB-055. The combination of morphological, chemical, and molecular markers assessment will be useful in studying the genetic diversity of Withania for identification, conservation, breeding, improvement activities, and in order to achieve elite type in terms of bioactive metabolites.     

Genetic Relationships in Malus Evaluated by RAPD 'Fingerprinting' of Cultivars and Wild Species

The potential use of RAPD markers for taxonomic studies in Malus was investigated using 18 accessions of wild species and 27 apple cultivars. 29 preselected random decamer primers were applied to three sets of Malus genotypes. Random amplified polymorphic DNA (RAPD) ‘fingerprints’ were analysed for polymorphic amplification fragments, and coefficients estimating genetic similarity were calculated on the basis of about 50 polymorphic RAPD loci in each set of genotypes. Cluster analysis by an unweighted pair-group method with arithmetic averages (UPGMA) revealed that, in the cultivars, the molecular classification was in good agreement with the known lineage. A dendrogram generated for the wild species gave relationships that were, in principle, in accordance with the known phylogenetic information. Closely related species from section I were clearly distinguishable from those of sections III and IV. On the molecular level, a high degree of genetic diversity was found among both different apple cultivars and wild species of the genus Malus. The results gave additional evidence for the hypothesis that M. pumila and M. sylvestris were involved in the origin of the cultivated apples.     

薄皮甜瓜种质资源遗传多样性的RAPD分析

RAPD分子标记对来源不同的41份薄皮甜瓜种质资源进行了遗传多样性分析。11个随机引物共扩增出78条带,平均每个引物扩增的多态性带数为5.3条,多态性带百分率为74.4%。利用NTSYS-pc软件计算种质间的遗传距离,用UPGMA法进行聚类分析,将供试的41份种质可分为3个类群8组,用EIGEN方法进行主坐标分析,将其分为4个类群12组。两种分类方法结果基本一致,后者能更为直观地反映群体之间的关系。     

瓠瓜种质资源遗传多样性的RAPD分析

采用RAPD分子标记对源自中国7个省份的38份瓠瓜种质资源进行遗传多样性分析.20个随机引物共扩增出104条多态性带,平均每个引物扩增的多态性带数为5.2条,多态性位点百分率为51.2%.利用NTSYS-pc软件计算种质问的遗传距离,用15PGMA法进行聚类分析,将供试的38份种质可分为3个类群8组,用EIGEN方法进行主坐标分析,将其分为3个类群13组.两种分类方法所获结果基本一致.RAPD分子标记表现出与瓠瓜的农艺性状分类和地区分布有一定的相关性.     

东南亚茄子种质资源ISSR遗传多样性分析

为探讨东南亚和中国华南地区茄子育种资源的遗传差异,研究采用ISSR分子标记对来自泰国和马来西亚的10份茄子材料及中国和南美的8份材料进行遗传多样性分析。结果表明,17条ISSR引物共扩增出433条谱带,其中多态性条带390条,平均多态率为92%。17条引物在18份材料中的平均观测等位基因数、平均有效等位基因数、平均Nei’s基因多样度和平均香农信息指数分别为1.8971、1.4778、0.2850、0.4336,18份材料间的遗传相似系数GS在0.55~0.81之间。运用NTSYSpc2.10软件的UPGMA方法进行聚类分析,结果表明在遗传相似系数0.67时18份材料可分为2个类群,其中来自于东南亚的10份材料在第1类群,来自于南美的3份材料在第2类群。研究结果表明,东南亚茄子材料与中国和南美茄子材料间遗传多样性丰富,可为茄子种质资源的进一步研究和利用提供理论依据。     

首批海岛棉基因组来源的微卫星标记的分离、评价和定位

海岛棉(Gossypium barbadense)是世界上最重要的栽培棉种之一。海岛棉纤维品质优良,是优质棉的重要产源。为了研究海岛棉的遗传多样性,为海岛棉育种提供参考依据,从海岛棉遗传标准系中分离基因组来源的微卫星标记用于海岛棉遗传评价。采用两种方法分离微卫星标记,一是用ISSR (inter simple sequence repeat) 引物扩增Pima3-79,克隆测序后从中开发微卫星标记;二是利用简并引物扩增Pima3-79,克隆测序后从中开发微卫星标记。共挑选1 447个克隆,筛选出239个独立克隆。测序后得到214个单一序列,其中包含微卫星并可用于引物设计的序列70个,获得86对引物。86对引物用于扩增56个海岛棉材料和4个陆地棉材料,16对引物没有扩增,43对引物在所有材料中没有多态性;27对引物在海岛棉和陆地棉之间有多态性,19对引物在海岛棉中表现多态性。利用Jaccard相似系数和UPGMA方法进行聚类分析可以明显区分陆地棉和海岛棉,并且将海岛棉分为4类。14对引物在BC₁群体中表现多态性,产生14个位点。9个位点整合到BC₁连锁图的7个染色体上,4个位于A亚基因组,5个位于D亚基因组。海岛棉微卫星标记扩展了棉花微卫星标记,有助于海岛棉遗传多样性的研究,有利于棉花遗传图谱的进一步丰富。     

Genetic relationships of sesame germplasm collection as revealed by inter-simple sequence repeats

Inter‐simple sequence repeats (ISSR) polymorphism was used to determine genetic relationships among 75 Sesamum indicum L. accessions of Korean and exotic sesame. Fourteen reliable ISSR primers were selected for the assessment of genetic diversity, yielding 79 amplification products. Of these polymerase chain reaction products, 33% revealed polymorphism among the 75 accessions. Genetic distances ranged from 0 to 0.255, with a mean genetic distance of 0.0687. The 75 accessions were divided into seven groups on the basis of unweighted pair‐group method with arithmetic averages (UPGMA) cluster analysis. The largest group consisted of 25 Korean cultivars, eight Korean breeding lines and 17 world‐wide accessions. The other groups included 25 accessions, several of which contained useful traits. The dendrogram did not indicate any clear division among sesame accessions based on their geographical origin. However, all Korean sesame cultivars except ‘Namsankkae’ were clustered in the same group, indicating a narrow gene pool. Some of the Korean breeding lines were spread along the dendrogram, showing enlargement of genetic diversity. The genetic diversity data uncovered in this study can be used in future breeding programmes.     

Genomic variation and genetic relationships in Ipomoea spp.

Random amplified polymorphic DNA (RAPD) markers were used to develop genetic fingerprints and analyse genetic relationships among 29 Ipomoea accessions from different geographical locations around the world, including unique wild species, and reproducible profiles were obtained for all accessions using random decamer primers. The primers generated 46 polymorphic markers, one primer alone having 10 products, enabling the discrimination of all 29 accessions. A high level of genetic variability in sweet potato collections was suggested by the degree of polymorphism. Half of the Japanese land races were closely related while accessions from Papua New Guinea and The Philippines were distinct and exhibited the greatest genetic diversity. The wild species Ipomoea gracilis and Ipomoea tiliacea formed a group distinct from the cultivated sweet potato. The wild tetraploid accession K233 and the species Ipomoea trifida were progressively more related genetically to the cultivated sweet potato and are the probable progenitors of Ipomoea batatas, and may be suitable as germplasm for genetic enhancement. RAPDs proved to be useful for sweet potato systematics and should be valuable for germplasm management, gene tagging and efficient choice of parents in breeding programmes.     

Assessment of genetic diversity among wheat (Triticum aestivum L.) cultivars from a range of localities across Pakistan using random amplified polymorphic DNA (RAPD) analysis

Genetic diversity among 20 wheat genotypes/cultivars from diverse locations of Pakistan was studied using random amplified polymorphic DNA (RAPD) analysis. A total of 445 DNA fragments were amplified with50 random decamer primers 64.38% of which were polymorphic. Genetic similarity matrix based on Nei & Li's (1979) index detected coefficients ranging from 75.60% to 92.74%. These coefficients were used to construct a dendrogram using unweighted pair group of arithmetic means (UPGMA). The wheat genotypes were clustered into one major group (A) and two small groups (B and C). The most distant genotype in the dendrogram was PARC-1 that was 75.60% to 84.94% genetically similar with the other genotypes and clustered with PARC-3 which formed a group distantly related with the other clusters. Moreover, most of the wheat genotypes developed from the same breeding centre clustered in one group. It has been clearly shown that most of the cultivars except PARC-1possessed narrow genetic background. The information would be helpful for future genome mapping programs as well as for the application of intellectual breeder rights in the country. The study will also work as indicator for wheat breeders to evolve varieties with diverse genetic background to achieve sustainability in wheat production in the country. This revised version was published online in August 2006 with corrections to the Cover Date.     

Genetic linkage maps of Citrus sunki Hort. ex. Tan. and Poncirus trifoliata (L.) Raf. and mapping of citrus tristeza virus resistance gene

The RAPD technique was used to identify genetic relationships in 19 accessions, including six species of the genus Chenopodium. A dendrogram was constructed using UPGMA from 399 DNA markers. The molecular data clustered species and accessions into five different groups. Group 1 with three cultivated varieties of C. nuttalliae, Group 2 included eight cultivars and two wild varieties of C. quinoa, Group 3 with C. berlandieri and C. album, Group 4 with two accessions of C. pallidicaule, and Group 5 with 2 accessions of C. ambrosioides. The polymorphic patterns generated by RAPD profiles showed different degrees of genetic relationship among the species studied. A low level of intraspecific variation was found within the accessions of C. quinoa, C. nuttalliae, and C. pallidicaule. The RAPD markers were found to be a useful tool for detecting genetic variation within the genus Chenopodium.     

Random amplified polymorphic DNA (RAPD) variation in Fagopyrum tataricum Gaertn. accessions from China and the Himalayan region

The diversity among 52 landraces and cultivars of tartary buckwheat (Fagopyrum tataricum Gaertn.) and one accession of its wild ancestor, F. tataricum ssp. potanini Batalin, from diverse geographic origins was examined using random amplified polymorphic DNA-polymerase chain reaction (RAPD-PCR) markers. Eighteen primers produced a total of 240 fragments, of which 153 (63.75%) were monomorphic and 87 (36.25%) polymorphic bands. UPGMA-based pairwise Jaccard’s coefficient of similarity was used to deduce the relationships among 53 genetically diverse accessions. The similarity between cultivated tartary buckwheat accessions ranged from 0.61 to 1.00. Four distinct clusters were formed which corresponded well with the geographic distribution of the tartary buckwheat. Nepalese accessions showed maximum diversity followed by Chinese accessions. Tartary buckwheat accessions from the Himalayan region of northwestern India revealed a narrow gene pool. The wild buckwheat accession did not group with any of the three cultivated tartary buckwheat groups, and formed its own single-entry group. Genetic similarity (0.59) of Chinese buckwheat accessions with the wild ancestor reaffirmed that cultivated tartary buckwheat originated in the Yunnan province of northwestern China. Consistent with some earlier reports, our study demonstrated the usefulness of the RAPD technique for the characterization of plant genetic resources and assessment of diversity between species. This revised version was published online in August 2006 with corrections to the Cover Date.