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1.
Forty-four accessions of cultivated peanut (Arachis hypogaea L.) representing sixbotanical varieties of two subspecies along with three accessions ofthe wild relative A. monticola Krapov et Rigoni were evaluated for their genetic relationships using theAFLP marker technology. Fifteen AFLP primer pairs (EcoRI/MseI) generated 28distinct polymorphic markers that were employed to develop uniqueprofiles of all accessions and to construct a phenogram. The resultsshowed that the botanical varieties aequatoriana and peruviana werecloser to subspecies hypogaea than subspeciesfastigiata Waldr. to which they belong, and the wildA. monticola was notdistinct from the cultivated A.hypogaea. Although the extent of geneticdiversity in peanut is low compared to many other crops, our studiesshow that by employing the AFLP approach, sufficient DNA variationcan be detected in the cultivated peanut germplasm to conductevolutionary studies.  相似文献   

2.
Genetic diversity among some important Syrian wheat cultivars was estimated using Amplified Fragment Length Polymorphism (AFLP) markers. Five Triticum aestivum L. and 10 Triticum turgidum ssp. durum were analyzed with 11 EcoRI–MseI primer pair combinations. Of the approximately 525 detected AFLP markers, only 46.67% were polymorphic. Cluster analysis with the entire AFLP data divided all cultivars into two major groups reflecting their origins. The first one contained T. aestivum L. cultivars, and the T. turgidum ssp. durum cultivars and landraces were grouped in the second. Narrow genetic diversity among all cultivars was detected with an average genetic similarity of 0.884. The lowest similarity index (0.9) was found between Cham5 and Hamary (durum wheat), whereas this value was 0.93 between Salamony and Bouhouth 4 (T. aestivum L.). The narrow genetic diversity level indicates that these genotypes could be originated from the same source. AFLP analysis provides crucial information for studying genetic variation among wheat cultivars and provides important information for plant improvement.  相似文献   

3.
Cowpea is an important grain legume and hay crop of many tropical and subtropical regions, especially in the dry savanna region of West Africa. The cowpea gene pool may be narrow because of a genetic bottleneck during domestication. Genetic variation within specific breeding programs may be further restricted due to breeding methods, ‘founder effects’ and limited exchange of germplasm between breeding programs. Genetic relationships among 60 advanced breeding lines from six breeding programs in West Africa and USA, and 27 landrace accessions from Africa, Asia, and South America were examined using amplified fragment length polymorphism (AFLP) markers with six near infrared fluorescence labeled EcoRI + 3/1bases/MseI + 3/1bases primer sets. A total of 382 bands were scored among the accessions with 207 polymorphic bands (54.2%). Despite a diverse origin, the 87 cowpea accessions shared a minimum 86% genetic similarity. Principal coordinates analysis showed clustering of breeding lines by program origin, indicating lack of genetic diversity compared to potential diversity. Accessions from Asia and the Americas overlapped and were distinct from West African breeding lines, indicating that germplasm from Asia and the Americas have common origins outside West Africa. US and Asian breeding programs could increase genetic variability in their programs substantially by incorporating germplasm from West Africa, while national programs in West Africa should consider introgression of Asian germplasm and germplasm from other parts of Africa into their programs to ensure long-term gains from selection.  相似文献   

4.
A total of 561 amplified fragment length polymorphism (AFLP) loci were generated and used to study the genetic diversity of wild and cultivated genotypes of pigeonpea. Out of 561 marker loci, 558 were polymorphic with an average of 76.12 bands. Analysis of molecular variation (AMOVA) revealed significant strong population structure when genotypes were structured according to continent of origin (FST = 0.22) also when structured into cultivated and wild genotypes (FST = 0.16). Maximum polymorphic loci were observed in cultivated species C. cajan (352) which is due to more number of genotypes used while, a minimum number of 45 polymorphic bands were obtained in C. acutifolius. Highest (0.291) average gene diversity was recorded in species C. mollis and lowest (0.079) average gene diversity was recorded in C. acutifolius. The 33 genotypes grouped into 14 clusters at 26% Jaccard’s similarity coefficients. Clustering analysis revealed most cultivated genotypes grouped into one major cluster while, the wild genotypes grouped into many clusters at 26% Jaccard’s similarity revealing greater diversity within wild species as compared to cultivated genotypes. From among the various cultivated genotypes studied, four genotypes BRG 3, ICP 7035, TTB 7 and ICP 8863 were molecularly and morphologically diverse and were used as parental genotypes to study nature of inheritance and to identify markers linked to sterility mosaic disease.  相似文献   

5.
Genetic variation and relationships among members of the azuki bean complex (Vigna angularis) including wild (V. angularis var. nipponensis), weedy, and cultivated types (V. angularis var. angularis), V. nakashimae, and rice bean (V. umbellata) from Korea were examined using the Amplified fragment length polymorphism (AFLP) method. AFLP analysis of 50 accessions revealed 333 (72.1%) polymorphic fragments out of 462 fragments amplified using seven primer combinations. The number of polymorphic fragments within each species was 70 in the azuki bean complex and 41 in V. nakashimae, but there was no polymorphism in rice bean. The number of shared fragments among species ranges from 142 between the azuki bean complex and V. nakashimae to 166 between the azuki bean complex and rice bean. Within the azuki bean complex, the range of shared bands was from 231 between cultivated and weedy types to 238 between cultivated and wild types. A dendrogram generated from Jaccard’s similarity matrix was divided into three groups, which correspond to V. nakashimae, azuki bean complex, and rice bean. The relationship between azuki bean and rice bean is closer than between azuki bean and V. nakashimae. Phenetic distances averaged 0.502 between the azuki bean complex and V. nakashimae and 0.467 between the azuki bean complex and rice bean. Within the azuki bean complex, the weedy type was more closely related to wild than cultivated types. But UPGMA dendrogram of the azuki bean complex reveals that each type is not clearly isolated. These results will help to understand genetic diversity and evolutionary dynamics of Vigna in Korea.  相似文献   

6.
Yams (Dioscorea spp.) rank as the fourth most important root and tuber crop after potatoes, cassava and sweet potatoes. They are an economic crop in most of the tropics especially in West Africa, which produces over 95 % of the world output. Despite their cultural and economic importance there is taxonomic confusion regarding Guinea yams. The currently used classification scheme, which relies on vegetative and inflorescence characters, does not consistently delimit species boundaries between members of Guinea yams (D. cayenensis Lam.–D. rotundata Poir. complex), their wild relatives (D. abyssinica Kunth and D. praehensilis Benth.,) and D. sagittifolia Pax. Establishing the taxonomic identity of the germplasm and understanding the systematic relationships among crops is vital to the management of genetic resources and the utilization of accessions. In this study, amplified fragment length polymorphism (AFLP) genetic fingerprinting was used to evaluate and characterize 43 individual plants, belonging to different populations of wild and cultivated Guinea yams. The three primer combinations used in the AFLP analyses generated 158 scorable bands, with an overall polymorphism of 78 %. Ordination and cluster analyses of AFLP data failed to produce any clear species boundary between either the Guinea yam accessions or between them and their wild relatives. The average genetic similarity between the study individuals of Guinea yams and their wild relatives ranged from 60 to 100 %. The first, second and third principal coordinates axes cumulatively account for 77.45 % of the total variation. AFLP analyses also revealed a higher genetic divergence among cultivated Guinea yam accessions of the Sheko cultivars. Ordination and cluster analysis using UPGMA revealed no clear species boundaries between members of the complex. Thus, the taxonomy of these “species” needs to be revisited using other markers.  相似文献   

7.
Amplified fragment length polymorphism (AFLP) markers were used to characterize the genetic diversity within and among natural populations and cultivars of Hedysarum coronarium. Twelve populations within Tunisia were evaluated with three AFLP primer combinations. A total of 207 reproducible bands was detected of which 178 (86%) were polymorphic. The great discriminative power of AFLP markers and their ability to represent genetic relationships among Hedysarum plants was demonstrated. Genetic diversity within and among populations was assessed through Principal Component Analysis (PCA) and cluster analysis by using the Neighbor-joining clustering algorithm. AFLP technology has provided evidence of a high degree of intra- and inter-population genetic diversity in H. coronarium. AFLP banding patterns provided molecular markers correlated with the plants’ geotropism. In addition, AFLP markers can differentiate wild accessions from cultivars. Moreover, geographical origins did not correspond to population clustering.  相似文献   

8.
Amplified fragment length polymorphism markers were evaluated to determine the genetic diversity and relationships among cultivated and weedy ryes (Secale cereale L.) using a large global set of accessions. On the basis of 395 polymorphic bands resulted from nine PstI-MseI primer combinations, cultivated rye exhibited higher average genetic diversity (Ht?=?0.34) than that of the weedy rye (Ht?=?0.27), however, it had lower genetic differentiation (Fst?=?0.16). The average genetic diversity of cultivated rye varied from region to region ranging from 0.21 to 0.31. As expected, all cultivated accessions clustered together both in dendrogram and principal coordinate diagram indicating common breeding program selection criteria based on similar value-added agronomic characteristics. A clustering of cultivated rye accessions into groups based strictly on geographical origin was not found. The relationships among cultivated, weedy and wild ryes were discussed.  相似文献   

9.
Detection of genetic relationships between 19 chickpea cultivars and five accessions of its wild progenitor Cicer reticulatum Ladizinsky were investigated by using RAPD and ISSR markers. On an average, six bands per primer were observed in RAPD analysis and 11 bands per primer in ISSR analysis. In RAPD, the wild accessions shared 77.8% polymorphic bands with chickpea cultivars, whereas they shared 79.6% polymorphic bands in ISSR analysis. In RAPD analysis 51.7% and 50.5% polymorphic bands were observed among wild accessions and chickpea cultivars, respectively. Similarly, 65.63% and 56.25% polymorphic bands were found in ISSR analysis. The dendrogram developed by pooling the data of RAPD and ISSR analysis revealed that the wild accessions and the ICCV lines showed similar pattern with the dendrogram of RAPD analysis. The ISSR analysis clearly indicated that even with six polymorphic primers, reliable estimation of genetic diversity could be obtained, while nearly 30 primers are required for RAPD. Moreover, RAPD can cause genotyping errors due to competition in the amplification of all RAPD fragments. The markers generated by ISSR and RAPD assays can provide practical information for the management of genetic resources. For the selection of good parental material in breeding programs the genetic data produced through ISSR can be used to correlate with the relationship measures based on pedigree data and morphological traits to minimize the individual inaccuracies in chickpea.  相似文献   

10.
To evaluate the genetic diversity and to clarify the genetic relationships of Japanese peach cultivars, we analyzed the amplified fragment length polymorphism (AFLP) and traced the pedigree of 17 Japanese commercial peach cultivars and six traditional accessions. Sixteen AFLP primer combinations produced a total of 837 fragments and 146 polymorphic bands with a polymorphism percentage of 17.5%. All of the peach accessions could be identified from differences in at least 10 polymorphic bands. A cluster analysis showed that all the Japanese commercial peach cultivars, except ‘Kiyomi’ and ‘Jichigetsuto’, formed a major group consisting of three sub-groups. Of the six traditional accessions, four were genetically distant from the Japanese commercial peach cultivars while two accessions from China were classified into the Japanese commercial peach cultivars group. Both the AFLP analysis and pedigree tracing suggested that Japanese commercial peach cultivars are mainly derived from ‘Shanhai Suimitsuto’, one of the traditional accessions from China. Although the genetic relationships revealed by AFLP were generally in agreement with those shown by the pedigree information, some contradictions were found. Combining the AFLP results and pedigree information can provide a better understanding of the genetic relationships of Japanese peach cultivars.  相似文献   

11.
Amplified fragments length polymorphism (AFLP) was used to distinguish 20 cultivars of sesame (Sesamum indicum L.) and to elucidate the genetic relationship among these genotypes. The data were also used to estimate the usefulness of parameters currently used to assess the informativeness of molecular markers. A total of 339 markers were obtained using 8 primer combinations. Of the bands, 91% were polymorphic. Five primer combinations were able to distinguish all 20 cultivars used. None of the remaining three primer combinations could distinguish all accessions if used alone, but using all three combinations reduced the probability of a random match to 5 × 10−5. Polymorphic information content (PIC), resolving power (Rp) and marker index (MI) of each primer combination failed to correlate significantly with the number of genotypes resolved. Jaccard’s similarity coefficients ranged from 0.31 to 0.78. Fifteen cultivars were grouped by four UPGMA-clusters supported by bootstrapping values larger than 0.70. The grouping pattern was similar to the grouping generated by principal coordinate analysis. The results demonstrated that AFLP-based fingerprints can be used to identify unequivocally sesame genotypes, which is needed for cultivar identification and for the assessment of the genetic variability of breeding stocks. We recommend to use the number of cultivars identified by a primer combination instead of PIC, Rp and MI; and to calculate the maximal, instead of average probability of identical match by chance in the assessment of the informativeness of a marker for cultivar identification.  相似文献   

12.
Couepia is a genus distributed in tropical regions of America. The nut of some Couepia species is used as fresh fruit and oil source for local communities. Despite its critical situation of conservation and its economic potential, there is a lack of information on the genetic variability of Couepia species. This study examines AFLP variation among 40 accessions of Couepia collected in the Colombian Amazonian region, representing two species: Couepia dolichopoda and Couepia subcordata. The individuals were examined for 96 markers generated from four EcoRI/MseI primer pairs, with 80% polymorphism across all accessions studied. According to cluster analysis, 40 accessions were grouped into two major clusters, corresponding to the two species analyzed, except one case whose situation is discussed. In C. dolichopoda accessions, significant correlation between the clustering pattern and the geographical origin was detected; the extent of variation within and among its collect sites was examined by AMOVA. The knowledge about the genetic variability of the accessions examined contributes to development of Couepia conservational efforts.  相似文献   

13.
Thirty-four durum wheat cultivars representing the Tunisian durum (Triticum durum Desf.) wheat collection and seven wild species of wheat relatives (Triticum turgidum L., T. dicoccon Schrank., T. dicoccoides (Körn) Schweinf., T. araraticum Jakubz., T. monococcum L., Aegilops geniculata Roth, and Aegilops ventricosa Tausch) were analysed with amplified fragment length polymorphism (AFLP) and microsatellite (SSR) markers. Both marker systems used were able to differentiate durum wheat cultivars from the wild relatives and to specifically fingerprint each of the genotypes studied. However, the two marker systems differed in the amount of detected polymorphisms. The 15 SSR markers were highly polymorphic across all the genotypes. The total number of amplified fragments was 156 and the number of alleles per locus ranged from 3 to 24 with an average of 10.4. Two SSR markers alone, Xwms47 and Xwms268, were sufficient to distinguish all 34 durum wheat genotypes. The five AFLP primer pair combinations analysed yielded a total of 293 bands, of which 31% were polymorphic. The highest polymorphic information content (PIC) value was observed for SSRs (0.68) while the highest marker index (MI) value was for AFLPs (7.16) reflecting the hypervariability of the first and the distinctive nature of the second system. For durum wheat cultivars, the genetic similarity values varied between 31.3 and 81% for AFLPs (with an average of 54.2%), and between 3.6 and 72.7% for SSRs (with an average of 19.9%). The rank correlation between the two marker systems was moderate, with r = 0.57, but highly significant. Based on SSR markers, highest genetic similarity (GS) values were observed within the modern cultivars (37.3%), while the old cultivars showed a low level of GS (19.9%). Moreover, the modern cultivars showed low PIC and MI values. UPGMA Cluster analysis based on the combined AFLP and SSR data separated the wild wheat species from the durum wheat cultivars. The modern cultivars were separated from the old cultivars and form a distinct group.  相似文献   

14.
Twenty-five Pyrus communis L. cultivars including eight traditional Portuguese pears, and four commercial Pyrus pyrifolia (Burm.) Nak. (Japanese pear or `nashi') cultivars were analysed by RAPD and AFLP techniques focusing on their molecular discrimination and the assessment of their genetic relatedness. Twenty-five primers generated 324 RAPD markers, among which 271 (84%) were polymorphic. The AFLP technique, using seven primer combinations, revealed a similar level of molecular polymorphisms (87%), representing 418 polymorphic bands among a total of 478 scored in autoradiographs. The high reproducibility of RAPD and AFLP techniques was confirmed comparing DNA samples from different extractions and different digestions of DNA from the same plant. Three genetic similarity matrices and respective dendrograms were elaborated on using RAPD, AFLP or joint RAPD and AFLP data. Both molecular marker techniques proved their reliability to assess genetic relationships among pear cultivars. P. pyrifolia cultivars exhibit a closer genetic relatedness, clustering apart from P. communis cultivars. Within P. communis, `William's', as well as `Doyenne du Comice', cluster close to their hybrids. Most of the Portuguese cultivars tend to cluster together, indicating to constitute a relatively independent genetic pool, which can be of interest in pear breeding programs.  相似文献   

15.
Amplified fragment length polymorphism (AFLP) analysis was used to evaluate the genetic relationships and diversities of Chinese vegetable mustards. Fourteen pairs of primers generated a total of 366 scorable fragments among 16 accessions of Brassica juncea studied, of which 296 bands were polymorphic with an average of 21.1% polymorphic bands per primer combination. Genetic similarities were obtained using Nei and Li similarity coefficients, and a dendrogram of the 16 accessions was made by UPGMA clustering method. The Nei and Li Similarity coefficient value ranged from 0.63 to 0.88. This result indicated that the 16 accessions of B. juncea possessed high level genetic variations. The cluster analysis showed that the vegetable mustards could be grouped into two main groups and some minor rami, which was partially in accordance with the traditional classification that based on different edible organs of vegetable mustards. The incongruity between morphological and molecular classification might be attributed to the high selection pressure during domestication of Chinese vegetable mustards, producing some accessions with similar genetic backgrounds evolving into abundant morphological variations. The great diversification among Chinese vegetable mustards not only provides an excellent object for molecular evolution research of B. juncea but also is of great value for widening the genetic basis of breeding programs and breeding materials selection. Besides, our study also indicates that AFLP are informative and can provide significant insights for genetic diversity research in B. juncea.  相似文献   

16.
Levels of genetic variation and genetic structure of 15 wild populations and three domesticated populations of Capsicum annuum were studied by RAPD markers. A total of 166 bands (all of them polymorphic) and 126 bands (125 of them polymorphic) were amplified in wild and domesticated populations, respectively. Mean percentage of polymorphism was 34.2% in wild populations and 34.7% in domesticated populations. Mean and total genetic diversity were 0.069 and 0.165 for wild populations and 0.081 and 0.131 for domesticated populations. Parameters of genetic diversity estimated from 54 bands with frequencies ≥1 − (3/n) (n = sample size) showed that 56.7% of the total variation was within and 43.3% among wild populations, whereas 67.8% of the variation was within and 32.2% among domesticated populations. AMOVA indicated that total genetic diversity was equally distributed within (48.9 and 50.0%) and among (50.0 and 51.1%) populations in both wild and domesticated samples. Wild and domesticated populations were clearly resolved in a UPGMA dendrogram constructed from Jaccard’s distances (average GD = 0.197), as well as by AMOVA (17.2% of variance among populations types, p = 0.001) and by multidimensional scaling analysis. Such differentiation can be associated with domestication as well as different origin of gene pools of the wild (Northwestern Mexico) and cultivated (more probably Central Mexico) samples analyzed. The considerable genetic distances among cultivars (average GD = 0.254) as well as the high number of diagnostic bands per cultivar (33 out of 126 bands), suggest that genetic changes associated with domestication could have resulted from artificial selection intervening in different directions, but the inclusion of more domesticated samples might clarify the nature of distinctions detected here.  相似文献   

17.
Sweet potato (Ipomoea batatas L.) is the fifth most important crop in the developing countries after rice, wheat, maize and cassava. The amplified fragment length polymorphism (AFLP) method was used to study the genetic diversity and relationships of sweet potato accessions in the germplasm collection of Sokoine University of Agriculture, Morogoro and Sugarcane Research Institute, Kibaha, Tanzania. AFLP analysis of 97 sweet potato accessions using ten primer combinations gave a total of 202 clear polymorphic bands. Each one of the 97 sweet potato accessions could be distinguished based on these primer combinations. Estimates of genetic similarities were obtained by the Dice coefficient, and a final dendrogram was constructed with the un-weight pair-group method using arithmetic average. AFLP-based genetic similarity varied from 0.388 to 0.941, with a mean of 0.709. Cluster analysis using genetic similarity divided the accessions into two main groups suggesting that there are genetic relationships among the accessions. Principal Coordinate analysis confirmed the pattern of the cluster analysis. Analysis of molecular variance revealed greater variation within regions (96.19%) than among regions (3.81%). The results from the AFLP analysis revealed a relatively low genetic diversity among the germplasm accessions and the genetic distances between regions were low. A maximally diverse subset of 13 accessions capturing 97% of the molecular markers diversity was identified. We were able to detect duplicates accessions in the germplasm collection using the highly polymorphic markers obtained by AFLP, which were found to be an efficient tool to characterize the genetic diversity and relationships of sweet potato accessions in the germplasm collection in Tanzania.  相似文献   

18.
Comparative analyses of genetic diversity and phylogenetic relationshipsof sweetpotato (Ipomoea batatas (L.) Lam.) and its wildrelatives in Ipomoea series Batataswere conducted using amplified fragment length polymorphism (AFLP) and sequencedata from the internal transcribed spacer (ITS) region of the ribosomal DNA. LowITS divergence among thirteen species of ser. Batatasresulted in poorly resolved relationships. More variable AFLP characters werefound to be more efficient in characterizing genetic diversity and phylogeneticrelationships at both intra- and interspecific levels within ser.Batatas. Highly informative AFLP fingerprints of 36accessions representing 10 species of ser. Batatas weregenerated using only six primer combinations. Of the species examined,I. trifida was found to be the mostclosely related to I. batatas, whileI. ramosissima andI. umbraticola were the most distantlyrelated to I. batatas. The highlypolymorphic AFLP markers are a valuable tool in assessing genetic diversity andphylogenetic relationships of sweetpotato and its wild relatives.  相似文献   

19.
The extent and patterns of distribution of genetic variation among 80 sorghum (Sorghum bicolor (L.) Moench) germplasm accessions from Ethiopia and Eritrea were investigated using RAPD with 20 oligonucleotide primers. The primers generated a total of 147 polymorphic bands across the 80 accessions with a mean of 7.35 bands per primer. Estimation of the extent of variation by the Shannon-Weaver diversity index revealed an intermediate level of overall variation (H = 53), although the levels varied among regions of origin of the accessions. Partitioning of the total variation revealed considerable variation (77%) within the region of origin of the accessions and the remainder (23%) among regions of origin. Similarly, a large portion (94%) of the total variation was found within the adaptation zones compared to among the adaptation zones (6%). The results suggest a weak differentiation of the sorghum material both on regional and agro-ecological bases, which could be ascribed to the high rate of outcrossing in cultivated sorghum and its free natural hybridization with its wild and weedy relatives, as well as to seed movement by humans. The average genetic dissimilarity was found to be 36% among the 80 accessions and 13% among the 15 regions of origin. Cluster analysis failed to group accessions of the same region or the same adaptation zone, which further confirmed the weak differentiation of the material studied. The clustering pattern of the regions of origin was broadly concordant with previous clustering patterns obtained using morphological characters, in which regions with broad agro-climatic conditions were grouped together.  相似文献   

20.
Sixteen collections of the wild Musa species, Musa balbisiana Colla collected from different regions of India were studied for their intraspecific relationships using random amplified polymorphic DNA (RAPD) markers. Out of 80 primers screened, 34 primers produced reproducible bands and four primers among them showing polymorphic bands were used. In all, 43 DNA fragments were amplified averaging 10.75 per primer. Of these, 31 amplified fragments showed polymorphism (averaging of 7.75 per primer). The extent of polymorphism (74.6%) has indicated the existence of considerable variation at the DNA level within the species. The 16 accessions were clustered into four as against seven clusters obtained through morphotaxonomic characterization. The inter relationships based on geographical origin in comparison with molecular characterization have been discussed.  相似文献   

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