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1.
Target region amplification polymorphism (TRAP) markers were used to assess genetic variability among 38 germplasm accessions
and 10 commercial hybrids of spinach (Spinacia oleracea L.), an economically important leafy vegetable crop in many countries. Germplasm accessions with different geographic origins
and 10 commercial hybrids were examined. For assessing genetic diversity within accessions, DNA was extracted from 12 individual
seedlings from six germplasm accessions and two hybrids. A relatively high level of polymorphism was found within accessions
based on 59 polymorphic TRAP markers generated from one fixed primer derived from the Arabidopsis-like telomere repeat sequence and two arbitrary primers. For evaluating interaccession variability, DNA was extracted from
a bulk of six to 13 seedlings of each accession. Of the 492 fragments amplified by 12 primer combinations, 96 (19.5%) were
polymorphic and discriminated the 48 accessions from each other. The average pair-wise genetic similarity coefficient (Dice)
was 57.5% with a range from 23.2 to 85.3%. A dendrogram indicated that the genetic relationships among the accessions were
not highly associated with the geographic locations in which the germplasms were collected. The seven commercial hybrids were
grouped in three separate clusters, suggesting that the phenotype-based breeding activities tended to reduce the genetic variability.
This preliminary study demonstrated that TRAP markers are effective for fingerprinting and evaluating genetic variability
among spinach germplasms.
Mention of trade names or commercial products in this article is solely for the purpose of providing specific information
and does not imply recommendation or endorsement by the US Department of Agriculture.
The U.S. Government's right to retain a non-exclusive, royalty-free license in and to any copyright is acknowledged. 相似文献
2.
Jane M. Marita Julie M. Rodriguez James Nienhuis 《Genetic Resources and Crop Evolution》2000,47(5):515-526
The development of a core collection, one which represents the genetic diversity of a crop with minimal redundancy and increases utility of the collection as a whole, is especially important as the funding for germplasm collections decreases. With limited resources, it is difficult to manage large germplasm collections and disperse genetically diverse germplasm to plant breeders. An algorithm was developed to assist in selection of core collections based on estimates of genetic distance. The criteria for selection of the maximum genetically diverse set were based on rankings of genetic distance between an accession with respect to all other accessions. Depending on the size core which a user wished, a zone around each selected accession was determined and no other accession within these limits was selected. The premise for the algorithm was that the genetic variability represented in the core must be representative of the distribution of genetic distances within the population of interest. In the present study, the algorithm was used with RAPD-marker-based estimates of genetic distance for 270 Theobroma cacao L. accessions and 134 Capsicum accessions that chose a set representing 18.5% of the population and representing the breadth of RAPD-based variation. 相似文献
3.
V. Sérgio Emílio Dos Santos M. Aparecido Gimenes J. Francisco Montenegro Valls C. Romero Lopes 《Genetic Resources and Crop Evolution》2003,50(8):841-848
Some Arachis species are widely used as commercial plants, e.g. the groundnut A. hypogaea, an important source of good quality protein and oil, and A. pintoi and A. glabrata, that are utilized as forage species. Germplasm of most Arachis species is available in germplasm banks. However, little it is known about the genetic attributes of this germplasm, and mainly about its genetic variability, which is very important for its maintenance. In the present study RAPDs were used to assay the genetic variation within and among 48 accessions of five sections of the genus Arachis and to establish the genetic relationships among these accessions. Ten of 34 primers tested were selected for DNA amplification reactions since they yielded the largest numbers of polymorphic loci. A dendrogram was constructed based on data from the 10 primers selected. Eighty RAPD polymorphic bands were analyzed among the accessions studied. The relationships among species based on RAPDs were similar to those previously reported based on morphological, cytological and crossability data; demonstrating that RAPDs can be used to determine the genetic relationships among species of the different sections of the genus Arachis. In general, wide variation was found among accessions and low variation was found within the accessions that had two or more plants analyzed. However, higher polymorphism was found in the section Trierectoides and in one accession of A. major, indicating that generalizations should be avoided and each species should be analyzed in order to establish collection and maintenance strategies. 相似文献
4.
The genetic diversity and the relationships among a collection of Brassica napus L. European populations were evaluated using random amplified polymorphic DNA markers. The study included 33 accessions of
B. napus collected from Galicia (northwestern Spain) and 18 British cultivars, 16 accessions of B. napus and two accessions of Brassica oleracea L. used as controls. DNA from 25 individuals per population was analyzed using 18 decamer primers. One hundred thirty-eight
amplification products were scored of which 105 were polymorphic. These bands ranged in size from 350 to 2500 base pairs.
Similarity coefficients and cluster analysis were computed and six groups were obtained. Cluster I was the largest and included
all the landraces from northwestern Spain, except two accessions that grouped separately into Clusters III and IV, respectively.
A low level of genetic variability was detected among the B. napus Spanish genotypes, while considerable diversity was present among the British ones, which grouped into three groups, two
main clusters and one group formed by one accession. Cluster II included all commercial varieties grown in Great Britain whereas
Cluster V grouped local varieties maintained by the growers for many years. Cluster VI was a singularity formed by one entry.
British accessions of B. oleracea had the greatest dissimilarity with all the other populations and grouped separately in Clusters VII and VIII. As conclusion,
B. napus landraces used in northwestern Spain as leafy-green vegetable probably have an independent origin from B. napus crops grown in other European regions. Besides, separate domestication in northwestern Spain and Great Britain for a different
end use might have led to two distinct gene pools. 相似文献
5.
The identification of seedling resistance to white rust of crucifers was performed in a screening of a B. oleracea core collection with 400 accessions representing the genetic and geographic diversity of the species. Fifty seedlings per accession were tested against the Portuguese isolate Ac502 using the methodology and evaluation procedures developed by and . The percentage of resistant seedlings (%R) and the conventional rating criteria of the mean Disease Index (DI) based on the two different evaluation procedures of disease expression used, were compared and adopted as the criteria to rank the accessions for their interest as sources of resistance. A great variability of reactions was found between and within accessions of the core collection, ranging from complete resistance to full susceptibility. Sources of resistance were found namely among the cauliflowers, broccoli and tronchuda cabbages gene pools. Forty-seven accessions presented at least 20% of resistant seedlings. Nine accessions (the kales INRA18 and INRA62, the cauliflowers HRI4856, HRI4866 and HRI5424, the loose-head cabbage HRI11555, the savoy cabbage BRA848, the black broccoli HRI6318 and the Portuguese tronchuda cabbage ISA207) presented 50–78% of resistant seedlings and so they should be considered as potential and useful sources for direct use in breeding programs for white rust resistance. Fourteen inbred lines, representing the full range of disease expression, derived from resistant accessions of the core collection were also tested for resistance to other two Portuguese isolates (Ac503 and Ac504) and to a UK isolate. The results provided no evidence of differential reaction to the A. candida isolates tested. 相似文献
6.
Pigeonpea is an important pulse crop grown by smallholder farmers in the semi-arid tropics. Most of the pigeonpea cultivars
grown to date are selections from the landraces, with a narrow genetic base. With the expansion of the crop to newer areas,
problems of local importance are to be addressed. Hence, an economically feasible and faster germplasm evaluation mechanism,
such as a core collection, is required. This article describes the development of core collection from 12,153 pigeonpea accessions
collected from 56 countries and maintained at ICRISAT, Patancheru, India. The germplasm accessions from 56 countries were
placed under 14 clusters based primarily on geographic origin. Data on 14 qualitative morphological traits were used for cluster
formation by Ward’s method. From each cluster ≈10% accessions were randomly selected to constitute a core collection comprising
1290 accessions. Mean comparisons using Newman–Keuls test, variances’ comparisons by Levene’s test, and comparison of frequency
distribution by χ2-test indicated that the core collection was similar to that of the entire collection for various traits and the genetic variability
available in the entire collection is preserved in the core collection. The Shannon–Weaver diversity index for different traits
was also similar for both entire and core collection. All the important phenotypic associations between different traits available
in the entire collection were preserved in the core collection. The core collection constituted in the present study facilitates
identification of useful traits economically and expeditiously for use in pigeonpea improvement. 相似文献
7.
Genetic variability of Coffea arabica L. accessions from Ethiopia evaluated with RAPDs 总被引：1，自引：0，他引：1
A.P. Chaparro M.A. Cristancho H.A. Cortina A.L. Gaitán 《Genetic Resources and Crop Evolution》2004,51(3):291-297
The genetic diversity of 50 wild and semi-wild accessions of the Coffea arabica L. germplasm collection, gathered by the FAO and ORSTOM missions to Ethiopia, and maintained in Colombia by CENICAFE, was evaluated with RAPD markers. The evaluation was carried out in two phases: In phase one, the polymorphism of 8 Ethiopian accessions of different geographic origin, plus the cultivated variety 'Caturra' was assessed with the RAPD technique with forty-two 10-mer oligonucleotides. In phase two, 51 accessions were assessed with a set of 5 polymorphic primers that reproduced, with a correlation of 95%, the groups generated by the 24 polymorphic primers found in phase one. Principal Coordinate Analysis of molecular data revealed that a closely related group consisting of 86% of the Ethiopian C. arabica accessions evaluated are significantly different from the Caturra variety and could be used in a genetic breeding initiative to increase the variability of cultivated varieties. The results also indicate that a larger polymorphism is present in the Colombian replica of FAO Ethiopian coffee germplasm collection than previously reported. 相似文献
8.
Robert R. Wieners Shui-zhang Fei Richard C. Johnson 《Genetic Resources and Crop Evolution》2006,53(8):1531-1541
Kentucky bluegrass (Poa pratensis L.) is an important turf and forage grass species with a facultative apomictic breeding behavior. In this study, mature seed
and leaf tissue from 38 accessions of a USDA core collection of Kentucky bluegrass were analyzed with flow cytometry to characterize
the reproductive mode and DNA content for each accession. Major reproductive pathways for each accession were determined based
upon the presence and the position of the peaks observed and the known methods of reproduction for Kentucky bluegrass. While
the majority of the accessions exhibited facultative apomictic reproductive behavior with a combination of reduced, zygotic
and unreduced, parthenogenic embryo production, obligate sexual or obligate apomictic accessions were also found to be present
in this core collection. In addition, reduced, parthenogenic and unreduced zygotic embryos were also detected in several accessions.
Flow cytometric analysis of somatic tissue revealed a large range of DNA variation within this core collection. We also examined
the sensitivity of flow cytometry in analyzing bulked samples containing a large number of plants with varied DNA content
and determined that flow cytometry can effectively detect a plant having a different DNA content within a 15-plant bulk sample.
Overall the combination of mature seed and somatic tissue analysis generated important information for the Kentucky bluegrass
core collection and can be an effective and affordable tool to characterize even greater numbers of Kentucky bluegrass accessions. 相似文献
9.
Twenty-one apple accessions were characterised and classified taxonomically with randomly amplified polymorphic DNA (RAPD). The results were compared with morphological and isoenzymatic classifications of the same material by calculating the congruence between similarity matrices. The results confirmed the greater discrimination capacity of RAPD compared with isoenzymes, although the taxonomic clusters obtained with both types of markers were congruent. The genetic relationships calculated using RAPD and isoenzymes showed little congruence with the morphological relationships among accessions. Isoenzymatic markers are useful in germplasm banks to evaluate the diversity of newly introduced accessions. The use of RAPD markers are especially beneficial to discriminate between material that is genetically similar, to evaluate genetic variability within a collection and to choose the components of the core collection. 相似文献
10.
Genetic Diversity of Traditional Chinese Mustard Crops Brassica juncea as Revealed by Phenotypic differences and RAPD Markers 总被引：1，自引：0，他引：1
This investigation was aimed at exploring the genetic diversity among nine typical accessions of Chinese mustard crops using
random amplified polymorphic DNA (RAPD) markers and morphological comparison. Totally, 111 reproducible DNA bands were generated
by 16 arbitrary primers, of which 91 bands were proved to be polymorphic. Based on pair-wise comparisons of the amplified
bands, genetic similarities were obtained using Nei & Li's similarity coefficients and a dendrogram reflecting their relationships
was made using the unweighted pair–group method with arithmetic averages (UPGMA). The result of cluster analysis indicated
that the nine accessions were capable of being classified into two primary groups, one including accession 2 with expanded
root (root mustard), accession 3 with entirely expanded whole stem (long-stem mustard), accession 6 with edible leaves (leaf
mustard), accession 8 with edible seed stalk (seed stalk mustard) and another one including accession 4 with expanded basal
stem (short-stem mustard), accession 5 with bulgy petiole (leafy bulgy mustard), and accession 9 with mustard-rich seed (seed
mustard). Besides, accession 1 with expanded root (root mustard) and accession 7 with edible leaves and seed stalk (seed stalk
mustard) were independent of other accessions in the dendrogram. Additionally, by cluster analysis based on highly reproducible
RAPD markers, the accessions with similar edible parts of leaves or roots were not actually in the same phylogenetic groups.
This implied that they were probably derived from different geographical origins with dissimilar genetic background and possessed
higher genetic diversification. Furthermore, the results indicated that the traditional method for classifying Chinese mustard
crops was not much reliable as it was largely dependent on phenotypic behaviors. Meanwhile, the phenotypic differences among
individuals did not necessarily mean they must have sharp difference in genetic background as they met in the same group.
Undoubtedly, these results aforementioned make this crop quite interesting to researchers for further investigating the molecular
evolution of this special AABB group. 相似文献
11.
As an oilseed crop, the cultivation of Ethiopian mustard (Brassica carinata) is restricted only to Ethiopia. Even though geographic diversity is a potent source of allelic diversity, the extent of genetic diversity among germplasm material of Ethiopian mustard from different countries has not been assessed. Forty-three accessions, comprising 29 accessions from eight different geographic regions of Ethiopia and 14 exotic accessions from Australia, Pakistan, Spain, and Zambia were analysed for their genetic diversity using random amplified polymorphic DNA (RAPD) technique. A set of 50 primers yielded a total of 275 polymorphic bands allowing an unequivocal separation of every Ethiopian mustard accession. The usefulness of the 50 RAPD primers in measuring heterozygousity and distinguishing accessions was variable such that polymorphic information content (PIC) varied from 0.05 to 0.40, band informativeness (BI) from 0.05 to 0.65 and primer resolving power (RP) from 0.15 to 6.83. Jaccard's similarity coefficients ranged from 0.44 to 0.87 indicating the presence of a high level of genetic diversity. On the average, Australian and Ethiopian accessions were the most similar while, Spanish and Zambian accessions were the most distant ones. Cluster analysis grouped the 43 accessions into four groups, which has quite a high fit (r = 0.80) to the original similarity matrix. With no prior molecular information, the RAPD technique detected large genetic diversity among the 43 accessions from five different countries and their grouping by dendrogram and principal coordinate analysis (PCoA) was inclined towards geographic differentiation of RAPD markers. Conversely, RAPD differentiation along geographic origin was not apparent within the Ethiopian accessions. 相似文献
12.
EL-Habib Dakir María-Luisa Ruiz Pedro García Marcelino Pérez de la Vega 《Genetic Resources and Crop Evolution》2002,49(6):619-631
The genetic variation existing in a set of barley (Hordeum vulgare L.) landrace samples recently collected in Morocco was estimated. Two kinds of genetic markers, seed storage proteins (hordeins) and random amplified polymorphic DNA (RAPD), were used. Only six out of 31 landraces were subjected to RAPD analysis. Both kinds of markers, RAPD and storage proteins, yielded similar results, showing that the level of variation observed in Moroccan barley was high: all landraces showed variability; 808 different storage protein patterns (multilocus associations) were observed among 1897 individuals (2.32 seeds per association, on average) with an average of 43 multilocus associations per accession. In general, genetic variation within accessions was higher than between accessions. The 100 polymorphic RAPD bands generated by 21 effective primers were able to generate enough patterns to differentiate between uniform cultivars and even between individuals in variable accessions. One of the aims of this work was to compare the effectiveness of RAPD versus storage protein techniques in assessing the variability of genetic resource collections. On average hordeins were more polymorphic than RAPDs: they showed more alternatives per band on gels and a higher percentage of polymorphic bands, although RAPDs supply a higher number of bands. Although RAPD is an easy and standard technique, storage protein analysis is technically easier, cheaper and needs less sophisticated equipment. Thus, when resources are a limiting factor and considering the cost of consumables and work time, seed storage proteins must be the technique of choice for a first estimation of genetic variation in plant genetic resource collections. 相似文献
13.
Bernardette Primieri Carelli Lee Tseng Sheng Gerald Felipe Gobbi Grazziotin Sergio Echeverrigaray 《Genetic Resources and Crop Evolution》2006,53(2):395-400
Random amplified polymorphic DNA markers (RAPD) were used to estimate the variability of 35 tomato accessions (Lycopersicon esculentum Mill.). A total of 257 reproducibly scorable bands were obtained from 20 primers, 78.6% of which were polymorphic. The percentage
distribution of RAPD markers shows a bimodal distribution, and the frequency of rare alleles is similar in commercial and
landrace accessions. Genetic distances among accessions were calculated and a dendrogram showing the genetic relationships
among them was constructed allowing for the separation of four groups. Twenty out of 23 Brazilian landraces fell within one
group, whereas commercial cultivars were distributed in the four groups. AMOVA analysis of RAPD data showed that, despite
the high within Brazilian landraces and commercial cultivars variation, these two groups are significantly different, indicating
that landraces can be a source of variation for breeding programs. 相似文献
14.
Genetic diversity of eighteen accessions of Ae. geniculata (2n=28; UUMM) was assessed using the random amplified polymorphic DNA (RAPD) technique. We optimized RAPD conditions including the template DNA, the concentration of AmpliTaq DNA polymerase Stoffel fragment, and MgCl2 concentration for revealing polymorphisms. Thirty-eight decamer oligonucleotides were individually used as primers under optimized conditions. Seventeen of these primers produced polymorphic RAPDs among the 18 accessions of Ae. geniculata. Polymorphisms were recorded by noting presence or absence of an amplification product from the total genomic DNA. Comparisons of unique and shared amplification products of each pair of accessions were used to generate genetic similarity coefficients (GSCs). These GSCs were used to construct a phenogram using an unweighted pair-group method with arithmetical averages (UPGMA). The phenogram shows that RAPD data is useful in the measurement of genetic variation or similarity within a species. It also indicates that we can select eight or nine accessions of the eighteen accessions to maintain at least 80% genetic variability of the Chinese collection of Ae. geniculata.
Address for correspondence: Dr X-Y. Zhang, USDA-ARS-FRRL, Utah State University, Logan, UT 84322-6300, who is visiting the USA under an agreement between USDA-ARS and CMA-CAAS on germplasm resources. 相似文献
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17.
A polymerase chain reaction (PCR) based approach involving the directed amplification of minisatellite DNA region (DAMD-PCR)
was used to identify accession specific DNA markers and study genetic relationships between and within 15 accessions corresponding
to 11 species in genus Capsicum. A touch down PCR profile and unique chemical concentration of ingredients resulted in reproducible and reliable DNA amplifications.
The number of amplified products varied from 1 to 12 fragments depending on the template DNA and the primers. The DAMD-PCR
technique provided a total of 38 accession specific DNA markers (diagnostic DAMD-PCR) which can be utilized in accession identification,
preservation and genetic studies of Capsicum germplasm. Based on 1,292 polymorphic and monomorphic DNA markers directed with 22 minisatellite specific primers, accessions
were divided into four major groups, three of which corresponded to the three distinct Capsicum complexes. Capsicum chacoense was found to be the most distinct species. 相似文献
18.
Verónica Nilda Ispizúa Irma Rosana Guma Sergio Feingold Andrea Martina Clausen 《Genetic Resources and Crop Evolution》2007,54(8):1833-1848
Andean potato varieties are cultivated in the northwest of Argentina and constitute the most important staple food for the
local farmers. The genetic diversity of 155 accessions conserved at the Genebank of Balcarce (INTA) was tested using four
microsatellites. Three commercial potato varieties of Tuberosum group and one accession of Curtilobum group were used as outgroups.
The presence of bands was scored for each microsatellite and for each accession and the data were analysed by principal coordinate
analysis. The polymorphism information content was obtained for each molecular marker from banding patterns. Analysis of molecular
variance was carried out with a variable number of accessions for each landrace, from different departments and sites within
departments. More than one genotype was detected in the majority of the potato landraces. Some accessions within each landrace
did not differentiate. AMOVA revealed that most of the genetic variation occurred among sites within departments and among
local varieties. These findings are discussed considering the agricultural practices carried out in the Andean farming system. 相似文献
19.
Taro [Colocasia esculenta (L.) Schott] germplasm accessions collected from different parts of India were subjected to RAPD (Random Amplified Polymorphic DNA) analysis to assess the genetic diversity prevalent and also to test the genetic basis of morphotypic classification. Thirteen random decamer primers out of the 22 tested were used to analyse 32 taro accessions belonging to 28 morphotypes. Three out of these thirteen primers analysed showed 100 per cent polymorphism. Per cent polymorphism varied from 60 to 100 among the polymorphic primers. High genetic diversity was revealed as the similarity coefficient values ranged from 0.50 to 0.98. No two accessions analysed in the present study showed a similarity coefficient value of one thereby indicating their distinctness and presence of high genetic diversity in Indian taro germplasm. Dendrogram obtained from UPGMA analysis grouped 32 accessions in four clusters and three accessions were placed as outliers. Clustering pattern did not show any strict relationship with geographical distribution, morphotype classification and genotypic diversity. Further, accessions classified, as belonging to the same morphotypic group did not always cluster together. Presence of a very close genepool of the wild, weedy and cultivated forms with extreme levels of phenotypic and genotypic variation is suggested as the reason for high genetic diversity reported. Usefulness of DNA markers such as RAPD in characterising and assessing the genetic diversity in Indian taro germplasm is hereby demonstrated. 相似文献
20.
Reliable characterization of the variation among wild and cultivated yams in Nigeria is essential for improved management
and efficient utilization of yam genetic resources. RAPD and double stringency PCR (DS-PCR) analyses were used to investigate
genetic relationships and the extent of redundancy among 30 accessions of two cultivated, and 35 accessions of four wild yam
species collected from Nigeria. Twenty-five selected random decamer and two microsatellite primers were used individually
and in combination to generate DNA profiles for each accession of the six Dioscorea species. The number of amplified fragments varied from 7 to 18 fragments per primer/primer combination. Different levels
of intraspecific genetic diversity were found, with Dioscorea rotundata Poir. being the most variable. Based on identical profiles for the RAPD and DS-PCR primers, 12 duplication groups consisting
of a total number of 37 accessions were observed in the present study. An UPGMA analysis grouped the majority of plants according
to the species. Cultivated yams belonging to the D. cayenensis–rotundata species complex, which were classified into seven morphotypes/varietal groups, could be clearly separated into two major
groups corresponding to D. rotundata Poir. and D. cayenensis Lam. D. cayenensis cultivars exhibited a low level of intraspecific variation and were genetically close to the wild species Dioscorea burkilliana J. Miège. D. rotundata cultivars classified into six varietal groups showed a high degree of DNA polymorphism and were separated into two major
groups that appeared most closely related to Dioscorea praehensilis Benth. and Dioscorea liebrechtsiana de Wild. We propose, based on these results, that cultivars classified into D. cayenensis should be considered as a taxon separate from D. rotundata. The implications of intraspecific variability for the ex situ conservation of wild and cultivated yam germplasm in Nigeria are discussed. 相似文献