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1.
B. J. Stodart H. Raman N. Coombes M. Mackay 《Genetic Resources and Crop Evolution》2007,54(4):759-766
Bread wheat (Triticum aestivum L.) landraces held within ex situ collections offer a valuable and largely unexplored genetic resource for wheat improvement
programs. To maximise full utilisation of such collections the evaluation of landrace accessions for traits of interest is
required. In this study, 250 accessions from 21 countries were screened sequentially for tolerance to aluminium (Al) using
haematoxylin staining of root tips and by root regrowth measurement. The staining test indicated tolerance in 35 accessions,
with an intermediate response to Al exhibited in a further 21 accessions. Of the 35 accessions classified as tolerant, 33
also exhibited increased root length following exposure to Al. The tolerant genotypes originated from Bulgaria, Croatia, India,
Italy, Nepal, Spain, Tunisia, and Turkey. AFLP analysis of the 35 tolerant accessions indicated that these represent diverse
genetic backgrounds. These accessions form a valuable set of germplasm for the study of Al tolerance and may be of benefit
to breeding programs for expanding the diversity of the gene pool from which tolerant cultivars are developed. 相似文献
2.
Jinggui Fang Chih-Cheng T. Chao Philip A. Roberts Jeffrey D. Ehlers 《Genetic Resources and Crop Evolution》2007,54(6):1197-1209
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
3.
Tobias W. Eschholz Roland Peter Peter Stamp Andreas Hund 《Genetic Resources and Crop Evolution》2008,55(7):971-983
About 65 years ago, more than 150 Swiss maize landraces (Zea mays L. ssp. mays) of the flint type were collected and conserved ex situ. Due to the climatically and culturally diverse environment of the Alps, a considerable genetic diversity of this material
was assumed. To prove this, an efficient method was required to carry out genetic profiling of all the accessions in the Swiss
Gene Bank. Simple sequence repeat marker (SSR) profiling in combination with the visualization of the polymerase chain reaction
(PCR) products on agarose gels was chosen. Here a set of 19 different landrace accessions was analyzed to: (i) investigate
their genetic diversity, (ii) investigate and display the population structure and (iii) determine whether DNA bulks rather
than single plants can be used for such analyses. Four repeated samples of one accession were found to be much closer to one
another than to the rest of accessions. Furthermore, specific alleles were identified for several accessions. The PCR products
of the bulked DNA samples represented only a small part of the variation revealed by the analysis of individuals. Loci with
four base repeat motifs performed better in the analysis of bulks than loci with other repeat motifs. The correlation between
genetic distance matrices, based on the analysis of individuals and bulks, respectively, was significant. Thus, the single
plant approach allowed for sufficient differentiation of accessions, and DNA bulks visualized on agarose gels led to correlated
genetic distances although a limited number of alleles were detected. Although the limited resolution of agarose gels likely
causes some bias, profiling of larger sets with the individual plant approach appears feasible and more informative compared
to the bulk analysis we conducted. 相似文献
4.
Katarina Wedelsbäck Bladh Erland Liljeroth Gert Poulsen Flemming Yndgaard Agnese Kolodinska Brantestam 《Genetic Resources and Crop Evolution》2014,61(2):383-394
176 horseradish accessions from the Nordic countries Denmark, Finland, Norway and Sweden were analysed to estimate the level of genetic diversity and to propose conservation strategies for this cultivated plant. Most of the accessions were collected in old gardens of the Nordic countries but selections from European countries and Danish breeding lines were also included in the study. Since horseradish is mainly vegetative propagated the genetic diversity has been assumed to be small. However, using the AFLP method with three primer combinations we revealed a significant genetic diversity among Nordic horseradish. The analysis yielded 65 polymorphic bands and we found an overall diversity index of 0.5 (Shannon–Weaver). The highest diversity was found among the Finnish accessions followed by the Danish accessions. An overall AMOVA analysis indicated that 90 % of the variation could be explained by among accession variation. The AFLP data assigned the different accessions into groups that corresponded with their country of origin. A closer relationship was observed between the Swedish, Danish and some of the Norwegian accessions while the Finnish accessions separated more clearly from the other three countries. A possible explanation for the diversity is that horseradish probably has been introduced to the Nordic countries at many occasions during a long period of time. 相似文献
5.
6.
Yong-Jin Park Anupam Dixit Kyung-Ho Ma Ju-Kyung Lee Myoung-Hee Lee Chan-Sik Chung Miyuki Nitta Kazutoshi Okuno Tae-San Kim Eun-Gi Cho V. Ramanatha Rao 《Genetic Resources and Crop Evolution》2008,55(4):523-535
The present study demonstrates utilization of 11 microsatellite markers to explore genetic diversity held in Perilla frutescens (L.) Britt. landrace accessions growing on farms in different parts of Korea and Japan and to assess their genetic relationships.
All microsatellite loci were polymorphic and produced a total of 96 alleles ranging from 4 to 20, with an average of 8.7 alleles
per locus. Of the 96 alleles found, a total of 15 unique landrace-specific alleles were observed at 9 different loci. The
locus GBPFM203 provided the highest number of alleles (20), of which five were unique and each specific to a particular landrace
accession. The occurrence of unique, accession-specific alleles presented molecular evidence for the generation of new alleles
within on-farm collection of Perilla. The mean values of observed (H
O) and expected heterozygosity (H
E) were 0.39 and 0.68, respectively, indicating a considerable amount of polymorphism within this collection. A genetic distance-based
phylogeny grouped the two Perilla varieties, var. frutescens and var. crispa (Thunb.) Decne into two distinct groups. Accessions belonging to var. frutescens could also be divided into two subgroups at a close genetic distance (GD = 0.432). The overall clustering pattern did not
strictly follow the grouping of accessions according to their geographic origins. These observations are indicative of extensive
germplasm exchange among farms from different geographical regions. The genetic similarity observed among the Perilla landraces may be useful for future Perilla crop variety identification, conservation, and improvement programs. 相似文献
7.
Weiwei Wen Suketoshi Taba Trushar Shah Victor H. Chavez Tovar Jianbing Yan 《Genetic Resources and Crop Evolution》2011,58(2):189-207
Twenty maize landrace accessions regenerated and conserved in five maize genebanks were investigated for genetic integrity
using 1,150 Single Nucleotide Polymorphisms (SNPs) and 235 SNP haplotypes. The genetic diversity of three accessions changed
significantly in terms of the average number of alleles per locus. Ten out of twenty accessions had significantly different
SNP allelic frequencies, either after regeneration or in the same accession held in different genebanks. The proportion of
loci with significant changes in SNP allelic frequency was very low (37/1,150). Changes in the major allelic frequency (MAF)
for the majority of SNP loci (60.2–75.2%) were less than 0.05. For SNP haplotypes, the genetic diversity of four accessions
changed significantly in terms of average number of haplotype alleles and polymorphic information content (PIC) per locus.
The proportion of SNP haplotype alleles lost in the later generations ranged between 0 and 22.6%, and at the same time 0–19.9%
of the SNP haplotype alleles appeared in later generations, however, these were absent in the earlier generations. Dynamic
changes in genetic integrity, in terms of presence and absence of genes (alleles), by both SNP and SNP haplotype analysis
were detected during regeneration. A suboptimum number of ears harvested in one generation can be combined with those from
another, repeated regeneration to capture the diversity of the previous generation. Use of molecular markers during regeneration
of accessions can help in understanding the extent of genetic integrity of the maize accessions in ex situ genebanks and in recommending the best practice for maintaining the original genetic diversity of the genebank accessions. 相似文献
8.
Evaluation of genetic diversity of bread wheat landraces from Pakistan by AFLP and implications for a future collection strategy 总被引:1,自引:0,他引:1
Ryoko Hirano Akira Kikuchi Makoto Kawase Kazuo N. Watanabe 《Genetic Resources and Crop Evolution》2008,55(7):1007-1015
We used amplified-fragment-length polymorphism (AFLP) markers to evaluate genetic variation in a set of bread wheat (Triticum aestivum L.) landraces and improved materials. Landraces collected from different geographic and agro-ecological zones in Pakistan
in 1987, 1989 and 1991 were separated into two groups based on their geographic origins: northern (Himalaya) and south-western
(Balochistan) Pakistan. Six AFLP primer combinations detected 453 AFLP markers in the 43 landrace accessions and four high-yield
varieties (HYVs). Of these, 225 (49.67%) were rare (shared with < 5% of all accessions). Among these rare alleles, 23 (10.22%)
were common in the Himalaya (shared with > 10% of accessions collected there) but were not found in Balochistan. We conclude
that there is a higher probability of collecting rare alleles at overall, but which are in contrast locally common ones in
the Himalayan region. Gene diversity was 0.17 in the Himalayan group and 0.15 in the Balochistan group. Considerable genetic
variability was found in both groups. Accessions from different agro-ecological zones were indistinguishable by cluster analysis,
indicating intensive seed trading within the country. Cluster analysis indicated that the landraces and the HYVs are genetically
distinct; suggesting that genetic erosion of wheat landraces has been unlikely taken in place. This study provides an example
of how analysis of existing materials and data, can serve as a basis for future collection planning and conservation policies. 相似文献
9.
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
10.
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
11.
Yong-Bi Fu Sarah Guerin Gregory W. Peterson John E. Carlson K.W. Richards 《Genetic Resources and Crop Evolution》2003,50(7):743-746
Effectiveness of several bulking strategies was empirically assessed in detecting RAPD variations and determining genetic relationships of five flax (Linum usitatissimum L.) landrace accessions. Bulking ten individuals before and after DNA isolations generated consistent RAPD variations. About 30% of the polymorphic RAPD loci observed in the plant-by-plant (PBP) sample were difficult to score and/or undetected in the bulked samples of the same accession. Heterogeneity among the six bulked samples of the same accession was observed at 5.6% of the loci scored. The frequency of a specific RAPD band present in those individuals used to form a bulk was at least 1/11 for its detection in the bulked sample. In spite of these limitations, bulking still generated compatible genetic relationships of the five accessions from its PBP sampling. 相似文献
12.
Opaque endosperm is the main phenotypic indicator for waxy rice, but other phenotypic and genotypic variation among waxy rice
accessions has largely been ignored. Previous studies showed that wide diversity in starch physiochemical properties exists
in both indica and japonica waxy rices, especially for starch gelatinization temperature (GT) which could be divided into a high- and a low-GT group.
In the present study, amplified fragment length polymorphism (AFLP) and inter-simple sequence repeat (ISSR) molecular markers
were employed to examine genetic diversity and relationships of 56 waxy rice accessions. A total of 358 AFLP fragments were
amplified with five primer combinations, showing a high level of polymorphism (78.3%). A total of 190 ISSR bands were generated
with a single primer and a primer pair, showing a very high level of polymorphism (92.2%). The genetic distance matrices obtained
from the two sets of markers were significantly correlated (r = 0.731, P = 0.004). The dendrogram generated with combined AFLP and ISSR markers could clearly differentiate the indica and japonica groups. Newly released varieties and breeding lines within each subspecies tended to be clustered together, whereas landraces
were more distantly placed in the dendrogram. Only one AFLP band was found specific to the indica type, while no specific bands were found for starch GT. The implications for the conservation and breeding of waxy rice are
discussed. 相似文献
13.
AFLP (Amplified Fragment Length Polymorphisms) and SSR (Simple Sequence Repeat) markers were utilized to assess genetic diversity and relatedness between Vigna unguiculata subspecies. Three AFLP primer combinations and 10 SSR primer sets successfully identified closely related accessions, and the presence of heterogeneity in some accessions. AFLP methodology was successful in separating different species of Vigna. However, the level of intra-subspecies variation was as great as was the interspecies variation with both marker methods. The number of markers employed was insufficient to successfully group the subspecies into distinct clades. 相似文献
14.
Abdelhameed Elameen Siri Fjellheim Arild Larsen Odd Arne Rognli Leif Sundheim Susan Msolla Esther Masumba Kiddo Mtunda Sonja S. Klemsdal 《Genetic Resources and Crop Evolution》2008,55(3):397-408
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
15.
16.
Warren F. Lamboy James R. McFerson Anne L. Westman Stephen Kresovich 《Genetic Resources and Crop Evolution》1994,41(2):99-108
Summary Management of a genetic resources collection is more effective if a curator can accurately identify genotypes and accessions as well as assess intraspecific genetic relationships and the genetic structure of species. Consequently, a study was conducted to determine whether data from starch gel electrophoresis of a specific set of isozymes from plants of Brassica oleracea (cole crops) would be useful in answering four questions the answers to which are essential for effective curatorial activities: Can individual plants be identified? Can specific accessions be identified? What are the genetic relationships among botanical varieties within B. oleracea? What is the genetic structure of the species B. oleracea? Six loci from 4 enzyme systems (LAP, PGD, PGI, and PGM) were analyzed. Individuals and accessions could not usefully be identified using these isozymes, but genetic relationships within and genetic structure of the species were easily determined, resulting in specific recommendations for improving collection management. As expected, highly selected commercial lines exhibited less diversity than average, and so may be of limited value when trying to maximize diversity with a minimum number of accessions. In contrast, landraces and weakly selected lines are more diverse than average, and thus are useful in maximizing per accession diversity. Not only was 93% of the genetic variability in B. oleracea found among accessions and a mere 7% among varieties, but also a cluster analysis showed that accessions of a single botanical variety are often more similar to those of a different variety than to each other. These results suggest that in order to create a genetic resources collection of B. oleracea that faithfully represents the diversity in the species, a curator should assemble a broad array of accessions originating from diverse agroecological niches, having different levels of improvement, and representing all botanical varieties.Abbreviations LAP
Leucine amino peptidase
- PGD
6-Phosphogluconate dehydrogenase
- PGI
Phosphoglucoisomerase
- PGM
Phosphoglucomutase
- RAPD
Random amplified polymorphic DNA
- RFLP
Restriction fragment length polymorphism
- UPGMA
Unweighted pair-group method using arithmetic averages 相似文献
17.
S. I. Warwick R. K. Gugel T. McDonald K. C. Falk 《Genetic Resources and Crop Evolution》2006,53(2):297-312
Information on genetic diversity and genetic relationships among genotypes of Brassica carinata is currently limited. The objectives of this study were to evaluate patterns and levels of genetic diversity in B. carinata based on amplified fragment length polymorphisms (AFLP) as compared with Brassica juncea and Brassica nigra, and to evaluate agronomic and seed quality data for plants grown in the field in western Canada. A total of 296 AFLP bands
were generated from four primer pair combinations and scored for presence/absence in 66, 20 and 7 accessions of B. carinata, B. juncea and B. nigra, respectively. B. carinata was less genetically diverse than the other two species. Differences in diversity were evident in the proportion of polymorphic
loci within each species: 23, 35 and 50% for B. carinata, B. nigra and B. juncea, respectively. Pair-wise similarity measures based on the Jaccard coefficient were highest among accessions of B. carinata and showed the narrowest range: 0.911 (0.810–0.981) compared to B. nigra: 0.569 (0.438–0.660) and B. juncea: 0.715 (0.345–0.951). AFLP-based genetic distance information can be used by plant breeders to select diverse genotypes.
AFLPs are also useful for fingerprinting cultivars and two primer pair combinations were sufficient to uniquely identify all
the accessions of B. carinata. More variation among accessions was identified in the agronomic trial than had previously been described in studies of B. carinata in western Canada, but the data were too limited to draw conclusions regarding specific accessions. Overall, the findings
were in agreement with other published work describing the favourable agronomic potential of this species. 相似文献
18.
Mohammad Reza Naghavi Mohsen Mardi Seyed Mostafa Pirseyedi Mehrbanu Kazemi Payam Potki Mohammad Reza Ghaffari 《Genetic Resources and Crop Evolution》2007,54(2):237-240
Genetic diversity of 54 accessions of Aegilops tauschii from five countries was assessed using sequence-tagged microsatellites (or simple sequence repeats, SSRs) and amplified fragment
length polymorphisms (AFLPs). In the case of AFLP analysis, a total of 256 amplification products obtained, 234 of them were
polymorphic across all the 54 accessions. A total of 224 fragments were obtained from the 24 SSR primers and 219 of fragments
were polymorphic across all the genotypes screened. Based on both AFLP and SSR markers, the highest percentage of polymorphisms
were obtained in Iranian and accessions of unknown origin. The highest polymorphic information content (PIC) value was observed
for SSRs (0.82) while the highest marker index (MI) value was for AFLPs (8.5) reflecting the hyper-variability of the first
and the distinctive nature of the second system. Principal co-ordinate analysis (PCO) revealed congruent patterns of genetic
relationships for both data sets, but did not group accessions strictly according to their geographical origins. Poor correlation
was found between AFLP and SSR marker loci. This low association may be due to low number of AFLP and SSR markers. These results
show that molecular markers can help to organize the genetic variability and expose useful diversity for breeding purposes. 相似文献
19.
Genetic variation within and among several Sorghum populations from different agroecological zones in Malawi were investigated using random amplified polymorphic markers (RAPDs). DNA samples from individual plants were analyzed using 35 oligonucleotides of random sequence. Twenty five of these primers allowed amplifications of random polymorphic (RAPD) loci. Overall, 52% of the scored loci were polymorphic. Every accession was genetically distinct. The analysis of molecular variance revealed that the within-region (among accessions) variations accounted for 96.43% of the total molecular variance. Observed variations in allelic frequency was not related to agroecological differences. The degree of band sharing was used to evaluate genetic distance between accessions and to construct a phylogenetic tree. Further analysis revealed that the sorghum accessions analyzed were genetically close despite considerable phenotypic diversity within and among them. It is suggested that all the sorghum landraces currently available in Malawi should be conserved both ex situ and in situ to maintain the current level of genetic diversity. 相似文献
20.
Smallanthus sonchifolius is a periennal herb originally cultivated in South America and now grown in several other countries. Recently, greater attention
has been focused on this plant due to its agronomical, nutritional and pharmacological characteristics. In this paper the
application of RAPDs and AFLPs for the analysis of genetic diversity in a group of 5 Smallanthus sonchifolius landraces is presented. Both methods proceed through the direct analysis of DNA, and their results were compared with the
total phenolic content of each landrace and its morphological traits. Using 61 RAPD primers, 85 informative bands were identified,
corresponding to 28.7% of polymorphism. In comparison, only six selected AFLP primer pairs produced 84 informative bands,
with a similar percentage of polymorphism (23.4%). RAPD and AFLP markers were analyzed separately. Total phenolic content
varied twofold among the five landraces analysed, ranging from 3,494 to 6,849 mg/g. Each type of molecular marker resolved
two main groups that included the same genotypes, but with different within-group relationships among genotypes. The two groups
are consistent with some phenotypic characters but they do not reflect faithfully their geographical origin. Most notably,
the two groups comprise landraces with higher and lower total phenolic content, respectively. Dendrograms based on the two
molecular data sets graphically depicted the ability of both methods to differentiate all the cultivars studied. Data obtained
suggest that the two molecular markers applied are useful to investigate intra-specific genetic variability in Smallanthus sonchifolius, and predict well the total phenolic content of each landrace. 相似文献