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1.
Understanding genetic diversity is very useful for scientific utilization for breeding. In this study, we estimated the genetic distances in a panel of 84 kenaf accessions collected from 26 countries and regions using ISSR markers. The results of UPGMA analysis showed that kenaf germplasm had abundant genetic variation, with genetic dissimilarity coefficients ranging from 0.01 to 0.62. The in-group dissimilarity coefficient (0.29) was observed in 84 kenaf accessions, and all the accessions could be divided into three groups: cultivars (L1–1), relatively wild species (L1–2 and L1–3), and wild species (the others). Further in-group analysis in group L1–1 (0.19) revealed that the kenaf cultivars could be divided into five subgroups with distinct regional characteristics. It is imperative that genes be exchanged among all kinds of tested varieties from different origins. The results provide a useful basis for kenaf germplasm research and breeding.  相似文献   

2.
红麻(Hibiscus cannabinus L.)种质资源的鉴定与分类研究   总被引:1,自引:0,他引:1  
对300份野生红麻和337份栽培红麻的形态学鉴定发现,红麻的茎、叶、花、果等植物学性状的类型多样,差异明显,遗传多样性十分丰富。野生红麻和栽培红麻一样,染色体数为2n=36,同属红麻种(Hibiscus cannabinus L.);核型有2n=36=32M+2SM+2M(SAT)、2n=36=34M+2M(SAT)和2n=36=32M+2ST+2M(SAT)等;综合形态学研究结果,将野生红麻分为普通、多毛、螺旋花和扁圆果4种类型,其中普通型又可分为3个亚类,普通型与栽培红麻亲缘关系最近,并发现红麻存在亚种。栽培红麻可分为9个变种17个类型,其中4个为新发现变种,7个为新发现类型。  相似文献   

3.
Kenaf (Hibiscus cannabinus L.) and roselle (H. sabdariffa L.) are valuable fibre crop species with diverse end use. Phylogenetic relationship of 73 accessions of kenaf, roselle and their wild relatives from 15 countries was assessed using 44 inter-simple sequence repeat (ISSR) and jute (Corchorus olitorius L.) specific simple sequence repeats (SSR) markers. A total of 113 alleles were identified of which 61.95 % were polymorphic. Jute specific SSR markers exhibited high polymorphism and resolving power in kenaf, although ISSR markers exhibited higher resolving power than SSR markers. Number of polymorphic alleles varied from 1 to 5 for ISSR and 1 to 6 for SSR markers. Cultivated species exhibited higher allele polymorphism (57 %) than the wild species (35 %), but the improved cultivars exhibited lower genetic diversity compared to germplasm accessions. Accessions with common genetic lineage and geographical distribution clustered together. Indian kenaf varieties were distinct from cultivars bred in other countries and shared more genetic homology with African accessions. High genetic diversity was observed in the Indian (J = 0.35–0.74) and exotic kenaf germplasm collections (J = 0.38–0.79), suggesting kenaf might have been introduced in India from Africa through Central Asia during early domestication. Genetic similarity-based cluster analysis was in close accordance with taxonomic classification of Hibiscus.  相似文献   

4.
DNA指纹图谱对新品种选育、种质资源保存和管理具有重要的意义。然而,利用SSR标记构建红麻DNA指纹图谱的研究仍十分有限。在本研究中,利用课题组开发并筛选出的131对SSR引物,分析不同来源的96份红麻种质资源,包括红麻品种审定的区试对照品种福红952。结果表明,131对引物共扩增出375条带,平均每对引物扩增出2.6条带。以遗传相似系数0.614为切割线时,可以分为2个类群,52个为类群P1,44个为类群P2;以遗传相似系数0.710做切割线,可分为5个亚群。利用这131对引物标记所得的数据成功绘制了一份85个品种独特的指纹图谱,其中福红952可被HcEMS238引物特异识别。其他11份因存在遗传相似性高的现象,未被识别。上述结果为红麻品种的真实性鉴定及遗传多样性分析提供依据。  相似文献   

5.
Kenaf is a multipurpose crop, but a lack of genetic information hinders genetic and molecular research. In this study, we aimed to develop EST-SSR markers from mutant and wild-type cultivars, and to assess the genetic diversity of the kenaf resources. A total of 33 Gb of sequence data comprising 130,480 unigenes was assembled by de novo RNA-sequencing of six kenaf cultivars, and 5619 SSRs were identified. Tri-nucleotide motifs occurred most frequently (82.67%) followed by di-, tetra-, and penta-motifs. In total, 515 polymorphic EST-SSRs were derived by pairwise comparisons of the cultivars based on in silico analyses. Of these, 70 markers were successfully validated among six cultivars. We used the six cultivars, together with 39 kenaf accessions from worldwide to assess genetic diversity and to characterize the EST-SSRs. The number of alleles per locus ranged from 2 to 8. PIC and genetic diversity values ranged from 0.08 to 0.79 and 0.08–0.82, respectively. The phylogenetic and population structure showed that the 45 accessions could be clearly divided into three groups based on different days to flowering (DTF). Genetic differentiation among the DTF groups showed a proportionally high level of variance. Association analysis between the DTF and the markers revealed three significant associations. Furthermore, using a multiplex PCR with three markers, DTF could be perfectly discriminated. These markers will be useful in marker-assisted selection after further validation with segregating populations of kenaf.  相似文献   

6.
The genetic diversity of 255 taro (Colocasia esculenta) accessions from Vietnam, Thailand, Malaysia, Indonesia, the Philippines, Papua New Guinea and Vanuatu was studied using AFLPs. Three AFLP primer combinations generated a total of 465 scorable amplification products. The 255 accessions were grouped according to their country of origin, to their ploidy level (diploid or triploid) and to their habitat—cultivated or wild. Gene diversity within these groups and the genetic distance between these groups were computed. Dendrograms were constructed using UPGMA cluster analysis. In each country, the gene diversity within the groups of wild genotypes was the highest compared to the diploid and triploid cultivars groups. The highest gene diversity was observed for the wild group from Thailand (0.19), the lowest for the diploid cultivars group from Thailand (0.007). In Malaysia there was hardly any difference between the gene diversity of the cultivars and wild groups, 0.07 and 0.08, respectively. The genetic distances between the diploid cultivars groups ranges from 0.02 to 0.10, with the distance between the diploid accessions from Thailand and Malaysia being the highest. The genetic distances between the wild groups range from 0.05 to 0.07. First, a dendrogram was constructed with only the diploids cultivars from all countries. The accessions formed clusters largely according to the country from which they originated. Two major groups of clusters were revealed, one group assembling accessions from Asian countries and the other assembling accessions from the Pacific. Surprisingly, the group of diploid cultivars from Thailand clustered among the Pacific countries. Secondly, a dendrogram was constructed with diploid cultivated, triploid cultivated and wild accessions. Again the division of the accessions into an Asian and a Pacific gene pool is obvious. The presence of two gene pools for cultivated diploid taro has major implications for the breeding and conservation of germplasm.  相似文献   

7.
Summary Allozyme analysis was performed on 83 wild Phaseolus vulgaris accessions, representing a wide geographical distribution from Mesoamerica to Argentina, to determine levels of genetic diversity and geographic patterns of variability at nine polymorphic isozyme loci. The collection can be divided into two major groups, one consisting of accessions from Mexico, Central America, Colombia and Peru, and the other consisting of accessions from Peru and Argentina. One accession from northern Peru is distinct from the two major groups, and may delineate a transition zone between the two divergent groups. The level of genetic diversity within wild P. vulgaris (Ht=0.132) is comparable with those found in other Phaseolus species. There was no significant within-accession gene diversity (Hs=0.006); however, there is a moderate level of genetic diversity (Dst=0.126) between accessions. Our results are consistent with previous studies on the genetic diversity of wild P. vulgaris using phaseolin, the major seed storage protein of beans.  相似文献   

8.
Two molecular marker technologies, random amplified microsatellite polymorphism (RAMP) and simple sequence repeats (SSR), were used to determine genetic diversity of 27 accessions of the wild barley Hordeum vulgare ssp. spontaneum. 19 primer combinations were used to generate RAMP fragments and 16 SSR loci were analysed. A high level of polymorphism was found with both kind of markers as revealed by the mean polymorphism information content (PIC) values obtained: 0.838 and 0.855 for RAMP and SSR, respectively. Genetic dissimilarities between genotypes were estimated from RAMP and SSR data. A lack of correlation was found between both sets of data. This was reflected in the two dendrograms obtained which presented accessions clustered differently. The results suggest that both sets of markers reveal genetic variation induced by different mechanisms. The dendrogram produced from the RAMP dissimilarity estimates showed most of the groups related to the geographic origin of the accessions.  相似文献   

9.
野生狗牙根种质遗传多样性的SRAP研究   总被引:10,自引:0,他引:10  
易杨杰  张新全  黄琳凯  凌瑶  马啸  刘伟 《遗传》2008,30(1):94-100
采用SRAP分子标记技术, 对采自中国四川、重庆、贵州、西藏四省区的32份野生狗牙根(Cynodon dactylon)材料进行遗传多样性分析, 获得下述结果:(1)用14对引物组合共得到132条多态性条带, 平均每对引物扩增出9.4条多态带, 多态性位点百分率为79.8%, 材料间的遗传相似系数范围在0.591到0.957之间, 平均GS值为0.759, 这些结果说明, 供试野生狗牙根具有较为丰富的遗传多样性; (2)对所有材料进行聚类分析, 可聚为4类, 大部分来自相同或相似生态地理环境的材料聚为一类, 表明供试材料的聚类和其生态地理环境间有一定的相关性; (3)基于Shannon多样性指数估算了6个狗牙根生态地理类群内和类群间的遗传分化, 发现类群内遗传变异占总变异的65.56%, 而类群间遗传变异占总变异的34.44%; (4)对各生态地理类群基于Nei氏无偏估计的遗传一致度的聚类分析表明, 各生态地理类群间的遗传分化与其所处的生态地理环境具有一定的相关性。  相似文献   

10.

Cowpea (Vigna unguiculata (L.)) is an important crop for food security in Senegal; therefore, understanding the genetic diversity of local germplasm is relevant for crop improvement and genetic maintenance in the era of climate change. For this purpose, 15 microsatellite markers were used to estimate the genetic diversity of Senegalese cowpea germplasm, including 671 accessions grown in eight regions and 66 wild relatives and intermediate forms (weedy). For the cultivated, the main expected heterozygosity (mHe) ranged between 0.317 (Fatick) and 0.439 (South). A narrow genetic variation between accessions from the different regions was observed with genetic similarity ranging from 0.861 to 0.965 and genetic differentiation indices (Fst) between 0.018 and 0.100. The accessions from southern Senegal (Kédougou, Sédhiou, and Kolda regions) are more diverse than the others. However, the accessions from the North (Saint-Louis) are genetically different from other regions. The diversity analysis in wild relatives from Senegal, which had never been performed before, revealed that the wild/weedy forms remain more diverse than the cultivated with genetic diversity values (He) of 0.389 and 0.480, respectively. STRUCTURE software divided the Senegalese germplasm into five subpopulations. Three of them (i, ii, and iii) included only cultivated accessions from several regions, one (v) mainly from Saint-Louis, and one (iv) the wild/weedy with some cultivated accessions. Our results support the hypothesis that Vigna unguiculata var. spontanea is the wild progenitor of cowpea. The accessions from the South, the northern recession accessions, and the wild/weedy could serve as sources of new genes for the genetic improvement of cowpea in Senegal.

  相似文献   

11.
Guineagrass (Panicum maximum Jacq.) is a forage grass found in tropical and subtropical regions. It is an apomictic and tetraploid species from Africa. The objective of this study was to evaluate the genetic diversity of guineagrass accessions sampled from its regions of origin, which is in Tanzania and Kenya. In this study, a total of 396 accessions were analyzed, and a collection of reproducible and informative microsatellites was developed. Thirty microsatellites were employed to characterize these accessions. A total of 576 clones were sequenced from microsatellite-enriched libraries. Flanking primers were designed for 116 microsatellite loci and screened using a sample of 25 guineagrass accessions. The thirty selected polymorphic microsatellites employed in this study produced a total of 192 bands when evaluated in the 396 P. maximum accessions, with an average of 6.4 bands per microsatellite. Four genetic clusters were identified in the collection using STRUCTURE analysis, and these results were confirmed using AMOVA. The largest genetic variation was found within clusters (65.38%). This study revealed that the collection of accessions from the P. maximum region of origin was a rich source of genetic variability. The geographical distances and genetic similarities among accessions did not indicate a significant association between genetic and geographical variation, supporting the natural interspecific crossing between P. maximum, P. infestum and P. trichocladum as the origin of the high genetic variability and the existence of an agamic complex formed by these three species.  相似文献   

12.
Zombi pea (Vigna vexillata (L.) A. Rich) is an underutilized legume species and a useful gene source for resistance to biotic and abiotic stresses, although there is little understanding on its genetic diversity and structure. In this study, 422 (408 wild and 14 cultivated) accessions of zombi pea from diverse origins (201 from Africa, 126 from America, 85 from Australia, 5 from Asia and 5 from unknown origin) were analyzed with 20 simple sequence repeat (SSR) markers to determine its genetic diversity and genetic structure. The SSR markers detected 273 alleles in total with a mean of 13.6 alleles per locus. Polymorphism information content values of the markers varied from 0.58 to 0.90 with an average of 0.76. Overall gene diversity was 0.715. Gene diversity and average allelic richness was highest in Africa (0.749 and 8.08, respectively) and lowest in America (0.435 and 4.10, respectively). Nei’s genetic distance analysis revealed that the highest distance was between wild Australia and cultivated Africa (0.559), followed by wild West Africa and wild Australia (0.415). STRUCTURE, neighbor-joining (NJ), and principal coordinate analyses consistently showed that these zombi pea accessions were clustered into three major groups, viz. America, Africa and Asia, and Australia. NJ tree also suggested that American and Australian accessions are originated from East African zombi peas, and that the cultivated accessions from Africa and Asia were genetically distinct, while those from America were clustered with some cultivated accessions from Africa. These results suggest that Africa is the center of origin and diversity of zombi pea, and that domestication of this pea took place more than once in different regions.  相似文献   

13.
Most studies on the genetic diversity of common bean (Phaseolus vulgaris L.) have focussed on accessions from the Mesoamerican gene pool compared to the Andean gene pool. A deeper knowledge of the genetic structure of Argentinian germplasm would enable researchers to determine how the Andean domestication event affected patterns of genetic diversity in domesticated beans and to identify candidates for genes targeted by selection during the evolution of the cultivated common bean. A collection of 116 wild and domesticated accessions representing the diversity of the Andean bean in Argentina was genotyped by means of 114 simple sequence repeat (SSR) markers. Forty-seven Mesoamerican bean accessions and 16 Andean bean accessions representing the diversity of Andean landraces and wild accessions were also included. Using the Bayesian algorithm implemented in the software STRUCTURE we identified five major groups that correspond to Mesoamerican and Argentinian wild accessions and landraces and a group that corresponds to accessions from different Andean and Mesoamerican countries. The neighbour-joining algorithm and principal coordinate clustering analysis confirmed the genetic relationships among accessions observed with the STRUCTURE analysis. Argentinian accessions showed a substantial genetic variation with a considerable number of unique haplotypes and private alleles, suggesting that they may have played an important role in the evolution of the species. The results of statistical analyses aimed at identifying genomic regions with consistent patterns of variation were significant for 35 loci (~20 % of the SSRs used in the Argentinian accessions). One of these loci mapped in or near the genomic region of the glutamate decarboxylase gene. Our data characterize the population structure of the Argentinian germplasm. This information on its diversity will be very valuable for use in introgressing Argentinian genes into commercial varieties because the majority of present-day common bean varieties are of Andean origin.  相似文献   

14.
Coffee is an important beverage crop in the world and has a significant contribution to Kenya’s economy. Here, we analyzed the genome-wide distribution of microsatellites in the Coffea canephora genome. A total of 159,041 SSRs were identified, with an overall density of 308 SSRs per Mb. Tetra-nucleotide repeats are the most abundant, accounting for 32 % of the total SSRs. AT-rich motifs are dominant across all SSR repeat units, while GC-rich motifs were generally rare. A set of 100 SSRs was selected to amplify 96 coffee accessions, including 10 wild accessions collected from Mt. Marsabit (Kenya). Of these SSRs, 33 % generated clear polymorphic bands among all tested accessions, with an average of 3.9 alleles per SSR locus. Wild coffee species from Mt. Marsabit showed a close genetic similarity with cultivated accessions in Kenya, suggesting that the wild species in Mt. Marsabit played an important role in the domestication of cultivated coffee in Kenya. Significantly low pairwise genetic divergence was observed between cultivated and wild accessions in Kenya, suggesting a relatively narrow level of genetic basis among coffee germplasm in Kenya. In addition, cultivated and wild coffee accessions in Kenya show a great divergence from those in other countries. Our results not only provide molecular tools for genetic studies in coffee but are also helpful for conservation and coffee breeding programs in Kenya.  相似文献   

15.
Aegilops tauschii Coss. is the D‐genome progenitor of hexaploid wheat. Aegilops tauschii, a wild diploid species, has a wide natural species range in central Eurasia, spreading from Turkey to western China. Amplified fragment length polymorphism (AFLP) analysis using a total of 122 accessions of Ae. tauschii was conducted to clarify the population structure of this widespread wild wheat species. Phylogenetic and principal component analyses revealed two major lineages in Ae. tauschii. Bayesian population structure analyses based on the AFLP data showed that lineages one (L1) and two (L2) were respectively significantly divided into six and three sublineages. Only four out of the six L1 sublineages were diverged from those of western habitats in the Transcaucasia and northern Iran region to eastern habitats such as Pakistan and Afghanistan. Other sublineages including L2 were distributed to a limited extent in the western region. Subspecies strangulata seemed to be differentiated in one sublineage of L2. Among three major haplogroups (HG7, HG9 and HG16) previously identified in the Ae. tauschii population based on chloroplast variation, HG7 accessions were widely distributed to both L1 and L2, HG9 accessions were restricted to L2, and HG16 accessions belonged to L1, suggesting that HG9 and HG16 were formed from HG7 after divergence of the first two lineages of the nuclear genome. These results on the population structure of Ae. tauschii and the genealogical relationship among Ae. tauschii accessions should provide important agricultural and evolutionary knowledge on genetic resources and conservation of natural genetic diversity.  相似文献   

16.
烟草种质资源遗传多样性的IRAP和ISSR标记比较分析   总被引:7,自引:0,他引:7  
采用IRAP和ISSR两种分子标记方法,对国内外28份烟草种质资源进行聚类分析,并对两种方法的结果予以比较。结果如下:(1)用IRAP方法对供试材料进行PCR扩增,共得到214条条带,其中187条具有多态性,多态性比率达87.4%。当L1取值0.495时,可将28份材料划分为3个类群;L2取值0.34时,又可将第3类群划分为3个亚类群和3个单一品种组成的独立个类;(2)用ISSR方法进行PCR扩增时,共得到334条条带,其中250条有多态性,多态性比率为75%。当L1取值0.41时,可将28份烟草种质划分为2个类群和2个独立个类Coker176、BaSmaUovina,第一类群(Ⅰ)为来自美国的两个品种RG11和K730,其它24个品种为第二类群(Ⅱ);(3)IRAP和ISSR两种方法的相关系数为0.823(r0.01=0.478),说明这两种方法的结果高度相关,均可用来进行烟草种质资源遗传多样性的分析。用IRAP方法得到的品种间遗传相异系数(GD)平均为0.423,高于ISSR方法,而且条带更稳定、多态性比率更高,更易揭示不同品种材料的遗传差异。  相似文献   

17.
Assessment of genetic diversity within and between pearl millet landraces   总被引:4,自引:0,他引:4  
A minimum core subset of pearl millet [Pennisetum glaucum (L.) R. Br.], which comprised 504 landrace accessions, was recently established from the global pearl millet germplasm collection of ICRISAT. The accessions for this core were selected by a random proportional sampling strategy following stratification of the entire landrace collection (about 16,000 accessions) according to their geographic origin and morpho-agronomic traits. In this study RFLP probes were used to quantify the genetic diversity within and between landrace accessions of this minimum core using a subset comprising ten accessions of Indian origin. Twenty five plants per accession were assayed with EcoRI, EcoRV, HindIII and DraI restriction enzymes, and 16 highly polymorphic RFLP probes, nine associated with a quantitative trait loci (QTLs) for downy mildew resistance, and five associated with a QTL for drought tolerance. A total of 51 alleles were detected using 16 different probe-enzyme combinations. The partitioning of variance components based on the analysis of molecular variance (AMOVA) for diversity analysis revealed high within-accession variability (30.9%), but the variability between accessions was significantly higher (69.1%) than that within the accessions. A dendrogram based on the dissimilarity matrix obtained using Ward's algorithm further delineated the 250 plants into ten major clusters, each comprised of plants from a single accession (with the exception of two single plants). A similar result was found in an earlier study using morpho-agronomic traits and geographic origin. This study demonstrated the utility of RFLP markers in detecting polymorphism and estimating genetic diversity in a highly cross-pollinated species such as pearl millet. When less-tedious marker systems are available, this method could be further extended to assess the genetic diversity between and within the remaining accessions in the pearl millet core subset.  相似文献   

18.
Inter-simple sequence repeat (ISSR) markers were employed to detect the genetic diversity among 70 grape accessions including 52 clones of 17 Chinese wild grape species, seven interspecific hybrids, 10 Vitis vinifera L. cultivars, and one strain of Vitis riparia L. A total of 119 polymorphic bands with an average of 11.9 per primer were observed. The unweighted pair-group method (UPGMA) analysis indicated that the 70 clones or accessions had a similarity range from 0.08 to 0.93, indicating that abundant diversities exist among these accessions. Based on cluster analysis and principal coordinate analysis, all accessions could be divided into two major groups, the Chinese wild grape group, and the American and European cultivar group. The largest distance was found among V. riparia MichX, Vitis piasezkii, V. vinifera L. interspecific hybrid (Vitis binifera × V. labrusca) and the wild grapes native to China.  相似文献   

19.
The genetic variability of the Brazilian physic nut (Jatropha curcas) germplasm bank (117 accessions) was assessed using a combination of phenotypic and molecular data. The joint dissimilarity matrix showed moderate correlation with the original matrices of phenotypic and molecular data. However, the correlation between the phenotypic dissimilarity matrix and the genotypic dissimilarity matrix was low. This finding indicated that molecular markers (RAPD and SSR) did not adequately sample the genomic regions that were relevant for phenotypic differentiation of the accessions. The dissimilarity values of the joint dissimilarity matrix were used to measure phenotypic + molecular diversity. This diversity varied from 0 to 1.29 among the 117 accessions, with an average dissimilarity among genotypes of 0.51. Joint analysis of phenotypic and molecular diversity indicated that the genetic diversity of the physic nut germplasm was 156% and 64% higher than the diversity estimated from phenotypic and molecular data, respectively. These results show that Jatropha genetic variability in Brazil is not as limited as previously thought.  相似文献   

20.
用19个RAPD引物和12个ISSR引物对14份野牛橡胶树种质和我国的37份栽培品种进行了遗传多样性分析。RAPD引物共产生132条带,多态性带占88.6%,相似系数变化范围在0.432—0.947。ISSR引物其产生101条带,多态性带占87.1%,相似系数为0.505—0.941。平均基因杂合度分析表明野生种质比栽培品种具有较高的遗传多样性。根据UPGMA法对51份材料进行聚类分析,结果表明,ISSR分析中所有材料可分为2类:第一类为野生种质,第二类为栽培品种:而RAPD分析中野牛种质和栽培品种不能被分为明显的两人类。虽然ISSR和RAPD的聚类分析结果存在差异,但对两种方法进行的相关分析表明,他们之间仍存在极显著相关性,相关系数为0.574。品种PR107、热研217等一些栽培品种可以通过特异带在51份供试材料中被区分开。这些结果可以对橡胶树的育种上作起到一定的指导作用,同时RAPD和ISSR技术也是进行橡胶树品种鉴定和遗传多样性研究的有效手段。  相似文献   

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