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1.
Native species show adaptive traits that are difficult to find in introduced species. The Pampas region in Argentina is a valuable nature reserve of grasses and Paspalum dilatatum Poir. is one of the most important grasses found there. Based on ploidy level and on morphological traits, five biotypes of P. dilatatum have been described. Two of them were included in this study: a tetraploid biotype with sexual reproduction and a pentaploid biotype with apomictic reproduction. We analyzed the genetic diversity in eight native populations from the Salado basin, Argentina, using both quantitative traits and molecular data (RAPD) with these aims: to obtain information of the degree of phenotypic variation in that area, to know which the pattern of distribution of this variation is and to look for association between molecular markers with populational or biotypic differentiation. Cluster analysis based on morphological data grouped the individuals of the different populations by ploidy level. Molecular markers showed the inverse situation because individuals were grouped by geographic origin as opposed to biotype. Moreover, since RAPD did not discriminate between biotypes with sexual or apomictic reproduction, they are probably not associated with mating system. The results let us conclude that polygenic traits such as LP, LBSR, NRT and NSP can discriminate between biotypes and molecular markers such as bands 12, 40, 19 and 46 can be used to discriminate among populations, probably because they detect neutral variation. The article is part of a thesis presented by María Victoria García in partial fulfillment of the requirements for the Doctor’s degree, Facultad de Ciencias Naturales y Museo, Universidad Nacional de La Plata, La Plata, Argentina.  相似文献   

2.
The genus Paspalum L. comprises approximately 400 species worldwide and about 220 in Brazil. Paspalum is ecologically and economically important, and has been very useful as pasture and P. notatum Flügge (bahiagrass) is a valuable forage grass in the subtropics. This species consists of several sexual (diploid) and apomictic (tetraploid, ocasionally tri and pentaploids) biotypes. In this work, inter simple sequence repeats (ISSR) markers were used to assess the genetic variability of a bahiagrass (P. notatum) collection. Vegetative tissues of 95 bahiagrass accessions were obtained from various locations in South America (Brazil, Argentina and Uruguay). A total of 91 reproducible ISSR fragments were observed and 89 fragments (97.5% of the total observed) were polymorphic. Cluster analyses (UPGMA) were performed from the ISSR data set and the results illustrate the genetic relationships among the 95 accessions of P. notatum. A comparison among molecular, morphological and ploidy levels data were done. ISSR markers were effective in distinguishing the genotypes analyzed, and a wide variability was observed for this species. These results add new information regarding the genetic diversity in P. notatum, thus contributing toward the biological knowledge of this species, and providing with subsides for future plant breeding and conservation programs.  相似文献   

3.
One hundred and thirty SSR markers from wheat, maize and sorghum were screened for the transferability to Paspalum. The transfer rate was 67.5, 49.0 and 66.8% respectively. This would be a very efficient approach for DNA marker development for species which are not well studied molecularly. The polymorphism level for transferred SSR markers was 51.5% within species (Paspalum vaginatum) and 87.1% among Paspalum species. The high level of polymorphism is directly related to the high degree of heterozygosity maintained by its way of reproduction, i.e. self-incompatibility. Forty transferred polymorphic SSR markers were selected and used for characterization and evaluation of seventy-three Paspalum accessions. In total, 209 polymorphic bands were detected from these 40 SSR markers, with an average of five polymorphic bands per marker. The Paspalum accessions clustered into three major groups. Two very similar dendrograms can be generated from either 109 or 209 polymorphic bands. This led us to determine that 18 of the transferred SSR markers were sufficient for genetically differentiating the investigated germplasm accessions. The number of SSR markers required for germplasm characterization and evaluation is discussed. This is the first report of the transfer of SSR markers from major field crops to newly emerged environmental turfgrasses.  相似文献   

4.
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5.
Andrographis paniculata is a medicinal plant of immense therapeutic value. The present study was aimed to elucidate its genetic diversity based on morphochemical and RAPD markers from 53 accessions belonging to 5 eco-geographic regions. Analysis of variance and D 2 statistics revealed significant differences in all the metric traits and sufficient inter-cluster distances indicating considerable diversity among the accessions. The complementary approach of RAPD was used to evaluate the genetic dissimilarities among all the accessions using 6 highly polymorphic primers. The average proportion of polymorphic loci across primers was 96.28%. The molecular genetic diversity based on Shannon index per primer averaged 5.585 with values ranging from 3.08 to 8.70 indicating towards wide genetic base. RAPD based UPGMA and D 2 cluster analysis also revealed that various accessions available in different eco-geographic regions might have originated from native places of wild abundance. Similarity matrices were generated for molecular markers and morphometric data to determine the degree of congruence between the two. A highly significant but low correlation (r = 0.547, P < 0.001) was obtained thus implying the correspondence between the two. The species is hermaphroditic and a habitual inbreeder. The present study yielded a typical triangular congruence between its breeding system, morphometric traits and RAPD markers thus elucidating the usefulness of complementary approaches to make diversity analysis more explanatory and purposeful for optimum genetic amelioration and effective conservation of its genotypic variability.  相似文献   

6.
Amplified fragment length polymorphism (AFLP) markers were evaluated for determining the phylogenetic relationships, and the diversity in the Saccharum complex using 30 clones belonging to S. officinarum, S. robustum, S. spontaneum, S. barberi, S. sinense and the related genus Erianthus. The phenetic tree of the species clones based on AFLP data was consistent with the known taxonomical relationships. AFLP gave higher resolution of closely related species into discrete groups than that by RAPD and RFLP markers, reported earlier. The levels of diversity within the various Saccharum species were also found to be higher than those obtained previously with the same set of clones using RAPD markers. The intraspecies similarity in S. barberi and S. sinense was much higher than interspecies similarity suggesting a clear separation of the two, which are considered ‘horticultural species’. The genetic similarity matrix derived from a single primer combination highly correlated (r = 0.980) with that obtained from all the 12 primer combination used in the study, thus highlighting the efficiency of a single primer combination in delineating species relationships. All the primer combinations could identify markers that are specific to each of the species and the genus Erianthus. Among the species, specific markers were highest in S. spontaneum followed by S. robustum, S. barberi, S. officinarum and S. sinense. Erianthus had a distinct profile with 30% of the total amplified fragments being specific to it. This offers great scope for identifying intergeneric hybrids, which has been very difficult using morphological traits and RAPD markers. High degree of correspondence between the results from the cluster analysis based on Jaccard's similarity index, Neighbour Joining tree based on Sokal and Michener distance matrix and AFTD (Analyses Factorielle on Table of Distances) analysis clearly demonstrated that AFLP markers would be an appropriate tool in providing better information about the relationships among the species, estimation of diversity, and in revealing species and genus specific markers that could be directly applied in sugarcane breeding programmes.  相似文献   

7.
The phylogenetic relationship of cultivated apple and its closely related species is still not clear in the taxonomy of genus Malus. To try to find new evidence for the origin and evolution of the cultivated apple, random amplified polymorphic DNA (RAPD) markers of 14 taxa of Malus, among which a reference species (M. toringoides) and six presumably ancestral species of cultivated apple in the genus were investigated. The RAPD data obtained were used to construct both unrooted and rooted trees using TREECON software package. The result showed in our rooted tree that M. sieversii from the Xinjiang Autonomous Region of China is the species which is most closely related to the cultivated apple, M. domesticacv. `Golden Delicious'. The phylogenetic relationships among the species studied are discussed.  相似文献   

8.
In several regions of Italy as well as other parts of southern Europe, the heterogeneity of the land, the climate and the soil favour the survival in cultivation of a large number of landraces specifically adapted to local conditions. Knowledge on the level and distribution of their genetic variation can help to develop appropriate strategies, in order to suistainably manage in situ these germplasm resources at risk of genetic erosion. C. annuum is an herbaceous diploid species and is considered to be self-pollinating, although different rates of out-crossing have been recorded. We used random amplified polymorphic DNA (RAPD) and amplified fragment length polymorphism (AFLP) markers to assess genetic diversity within and between five populations of a landrace of Capsicum annuum L., grown in a limited area in north-west Italy and locally known as Cuneo pepper. Partitioning the genetic variation with Shannon's diversity index revealed that 41.6% occurred between and 58.4% within populations. Analogous results were obtained when the analysis was based only on RAPD or AFLP markers. However, AFLP was more reliable, since a lower range of variation was observed among primer combinations in detecting the two components of genetic variation. Notwithstanding the rather high level of within genetic variation detected, the five populations were clearly differentiated and differed in the frequency of alleles exclusive and/or present at very low frequencies. Our results show the need for accurate estimation of allele frequencies, in order to identify populations to which priority should be given for dynamic conservation of landraces.  相似文献   

9.
Molecular and morphological variation of six perennial and five annual species including domesticated chickpea, C. arietinum, were inferred on the basis of RAPD and S.E.M. seed coat features using three outgroup taxa (Lens ervoides, Lathyrus japonica and Pisum sativum). Of the 66 decamer arbitrary primers tested, eight primers revealed 87 informative fragments. Neighbor-joining cluster analysis using Jaccard's coefficient of similarity on the basis of polymorphic fragments indicated a narrow variation in C. arietinum and recognized two major clusters in the genus Cicer. The first one included four species of sect. Monocicer: C. echinospermum, C. arietinum, C. reticulatum and Iranian material of C. bijugum. The second cluster contained annual and perennial species belonging to sections Chamaecicer, Polycicer and Acanthocicer. The character state of morphological and ecological traits on the RAPD phenogram indicated no monophyletic incision. Our results suggested that the high genetic difference between annual and perennial species might be regarded as a rapid speciation of section Monocicer. Reconsideration of traditional classification of sections Polycicer and Acanthocicer is necessary. The Desi and Kabuli types of C. arietinum could not be separately grouped at the DNA level, and the low level of genetic variation of C. arietinum may result from a bottleneck during the domestication process.  相似文献   

10.
The genus Arachis is divided into nine taxonomic sections. Section Arachis is composed of annual and perennial species, while section Heteranthae has only annual species. The objective of this study was to investigate the genetic relationships among 15 Brazilian annual accessions from Arachis and Heteranthae using RAPD markers. Twenty-seven primers were tested, of which nine produced unique fingerprintings for all the accessions studied. A total of 88 polymorphic fragments were scored and the number of fragments per primer varied from 6 to 17 with a mean of 9.8. Two specific markers were identified for species with 2n = 18 chromosomes. The phenogram derived from the RAPD data corroborated the morphological classification. The bootstrap analysis divided the genotypes into two significant clusters. The first cluster contained all the section Arachis species, and the accessions within it were grouped based upon the presence or absence of the ‘A’ pair and the number of chromosomes. The second cluster grouped all accessions belonging to section Heteranthae.  相似文献   

11.
Vanilla is naturally distributed in Mexico and parts of Central America and the history of origin of cultivated vanilla suggests that the entire stock outside Mexico may be from a single genetic source. In the present study, RAPD polymorphism was used to estimate the level of genetic diversity and interrelationships among different collections of Vanilla planifolia Andr., and few related species, including both leafy and leafless types such as V. tahitensis J.W.Moore, V. andamanica, Rolfe, V. pilifera Holtt., and V. aphylla Blume. Studies revealed that there are very limited variation within collections of V. planifolia, indicative of its narrow genetic base, and of the related species we tested, V. tahitensis is nearest to V. planifolia. The species studied are diverse and have a similarity ranging from 1.2 to 57.3 %. Of the sampled taxa, V. andamanica is the most divergent and there is also reasonable variability within its collections, indicating the possibility of natural seed set. A total of 82 polymorphic bands expressed in the RAPD profiles were used to generate a genetic distance matrix, which was then used in cluster analysis. Specific groupings were revealed by the cluster analysis whereby the leafless forms (V. aphylla, V. pilifera and the new species) and V. andamanica formed separate clusters. This is the first report of species interrelationship studies, including both cultivated and wild vanilla species.  相似文献   

12.
Random-amplified polymorphic DNA (RAPD) markers were used to evaluate genetic variability among populations of an Italian strawberry ecotype, and to determinate genetic relationships between genotypes and their putative ancestor. A total of 65 selections and one cultivar ‘Madame Moutot’ (MM), were analysed to evaluate genetic variability present in Etna mountain area and to confirm as MM was one of the cultivars that originated the ecotype. A total of 222 RAPD markers was obtained using 16 decamer primers and 6 longer primers, 90.8% of the markers obtained by selected primers resulted polymorphic at least within analysed genotypes. RAPDs were used to calculate genetic similarity coefficients and to generate dendrograms representing genetic relationships among genotypes analysed. Cluster analysis displays as RAPD polymorphisms were able to characterize the genotype variability among closely related groups. The data show as MM could be considered the ancestral genotypes introduced in that area. The results obtained confirm that RAPD markers could be used as reliable markers to perform phylogenetic studies in Fragaria×ananassa Duch. ex Rozier. Giuseppe Bertino and Piero Spada - Coauthor involved in genotype selection and field management  相似文献   

13.
To assess the generic delimitation and the interspecific relationships between Hystrix and Elymus, three Hystrix and 10 Elymus species were used for random amplified polymorphic DNA(RAPD) assay. Of the 54 primers tested, 26 (48%) produced polymorphic products. A total of 167 products amplified from 16 primers were selected for RAPD analysis, among which 156 (93.4%) amplified products were found to be polymorphic among the 13 species. The polymorphism produced by each primer ranged from 4 to 13, with an average of 9.8. Data were used to generate Jaccard's similarity coefficients and to construct a dendrogram using UPGMA in the NTSYS computer programs. It is concluded from this study that: (1) there were clear differences between Hystrix and Elymus, which possibly suggest that Hystrix is a valid genus; (2) great diversity existed among the species of Hystrix and Elymus; (3) the species similar to each other in morphological characters were grouped together; (4) the species from neighboring geographical regions were clustered; (5) the species with the same genomes and polyploidy level were clustered together; (6) RAPD results are comparable with those obtained from studies on morphology and cytology. It is a useful additional method for assessing the relationships among genera and species in Triticeae.  相似文献   

14.
Malus sieversii (Ledeb.) Roem. is a wild apple species which is distributed in the western mountains in Xinjiang, P.R. China, as well as in Central Asia, including Kazakhstan, Kyrgyzstan, Tajikistan, Uzbekistan and Turkmenistan. M. sieversii germplasm is valuable for plant breeders for drought, cold and disease resistance. Genetic polymorphisms of 20 populations of M. sieversii and 2 populations of M. niedzwetzkyana in Xinjiang, China were analyzed using RAPD markers. We present geographical distribution data as well as the discovery of a rare king old tree. Different types of pollen grain morphology were analyzed.  相似文献   

15.
Randomly amplified polymorphic DNA (RAPD), inter-simple sequence repeat (ISSR) and a semi-random PCR system were used to analyze the genetic diversity of 16 Italian common bean landraces and their relationship to four commercial cultivars. Of the primers tested, 8 ISSR, 6 RAPD and 7 semi-random primers produced polymorphic and reproducible DNA fragments. A higher proportion of polymorphic bands were observed using ISSR (85%) and semi-random (90%) primers than RAPD (69%) method. The combination of any two semi-random markers allowed the identification of all 20 bean genotypes. In contrast ISSR (except for primer (CAC)3GC) and RAPD markers appeared to be less informative as more than two markers were necessary to achieve the same diagnostic level. Moreover, 7 ISSR, 2 RAPD and 8 semi-random exclusive bands were identified as putative population-specific markers. Semi-random and ISSR derived dendrograms showed similar tendencies in terms of genetic relatedness, whereas clustering of genotypes within groups was not similar when compared with the RAPD technique. Despite the different ability to resolve genetic variation among the investigated landraces, two major clusters with less than 60% (ISSR) and 40% (RAPD and semi-random) genetic similarity were formed with all three marker systems. The two groups were correlated with the phaseolin patterns and seed size of the landraces. The analysis showed that the cultivar ȁ8Lingua di Fuocoȁ9 and most of the landraces (13 out of 16) collected in Italy belong to the Andean gene pool, whereas only the three populations from Pratomagno belong to the Middle American gene pool.  相似文献   

16.
Variation for 24 morphological traits measured in a greenhouse environment and 36 randomly amplified polymorphic DNA (RAPD) markers was assessed among 318 wild octoploid strawberry (Fragariaspp.) genotypes from diverse habitats across the northern USA. RAPD marker frequencies and certain leaf and flower morphology traits (petiole color, leaf mass/area ratio, leaflet length and width, flower and receptacle diameter, petal width, flowers/inflorescence) were significantly different between the F. chiloensis-platypetala and F. virginiana-glauca species complexes. The proportion of variation accounted for by provenance effects was lower for the RAPD markers than for most morphological traits, especially in the F. virginiana-glauca species complex. Morphological traits of potential adaptive importance group the collection into provenances within each species-complex, and reflect the significant habitat and geographic differences across the region from which the germplasm was collected. Variation among populations within provenances was low for the molecular and most morphological traits, with a much larger amount of variability among plants within populations. Most of the variation for the presumably more selectively-neutral RAPD data was among plants within populations and populations within provenances rather than among the provenances that were recognized based on morphological traits, especially in the F. virginiana-glauca complex. Patterns of diversity for morphological traits must be considered, along with more selectively-neutral molecular characters such as RAPDs, to formulate effective sampling strategies and to properly estimate the quantity and apportionment of diversity within this germplasm.  相似文献   

17.
Ninety four accessions of the cultivated triploid potatoS. chaucha were analyzed and classified in genotypic groups using 9 isozyme loci and RAPD markers disclosed by 20 arbitrary 10-mer primers. Eight isozyme loci out of nine were polymorphic. A total of 22 allozymes were analyzed but none of them were specific for any genotypic group. About half (52%) of the 102 RAPD markers scored, were polymorphic, all of them showing polymorphism among groups and rarely within groups. Eighteen RAPD markers were specific for certain genotypes. The isozyme markers showed a certain amount of intra group variation which made classification less reliable than with RAPD markers. A total of 10 triploid genetic groups were discriminated using both techniques together. A single primer was found to be sufficient to distinguish all 10 groups. All varieties of a single group are considered to have been derived from the same cross and then clonally propagated, even though there is a high amount of morphological variation within a single genotypic group due probably to somatic mutations. RAPD markers have been shown to be more reliable in the classification of triploid potato varieties than other genetic markers like isozymes, proteins and morphological traits.  相似文献   

18.
Summary An analysis of the amplification fragments polymorphism of DNA coming from different accessions of germplasm belonging to species and cultivars of the genus Vitis, was carried out using 40 primer decamers of arbitrary sequence. The RAPD profiles showed a great intraspecific diversity. In many cases a single primer produced a unique pattern for each species. A phylogram tree based upon presence/absence data of the principal DNA bands divided the species according to their geographical origins. The intraspecific polymorphism of DNA fragments was not sufficient for an unambiguous identification of Vitis vinifera cultivars but the RAPD profiles turned out to be highly reproducible. The high capacity of this technique to generate DNA markers offers a new possibility for the study of the genetic relationships in the genus Vitis.Abbreviations PCR Polymerase chain reaction - RAPD Random amplified polymorphic DNA  相似文献   

19.
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20.
Thirty Portuguese and eight foreign olive (Olea europaea L.) cultivars were screened using Random Amplified Polymorphic DNA (RAPD) and Inter-Simple Sequence Repeat (ISSR) markers. Twenty RAPD primers amplified 301 reproducible bands of which 262 were polymorphic; and 17 ISSR primers amplified 204 bands of which 180 were polymorphic. The percentage of polymorphic bands detected by ISSR and RAPD was similar (88 and 87%, respectively). The genetic variability observed was similar in the Portuguese and foreign olive cultivars. Seven ISSR and 12 RAPD primers were able to distinguish individually all 38 olive cultivars. Twenty specific molecular markers are now available to be converted into Sequence Characterised Amplified Region (SCAR) markers. Relationships among Portuguese and foreign cultivars is discussed.  相似文献   

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