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Hirut Kebede Gloria Burow Raviprakash G. Dani Randy D. Allen 《Genetic Resources and Crop Evolution》2007,54(4):885-895
Since Upland cotton (Gossypium hirsutum) is known to have relatively low levels of genetic diversity, a better understanding of variation and relationships among
possible sources of novel genes would be valuable. Therefore, analysis of genetic variation of the genus Gossypium, especially the diploids, which are the putative donors of the A and D genomes for the commercially important allotetraploid
cottons (AADD), G. hirsutum and G. barbadense, could provide important information about the feasibility of using these genetic resources for cotton improvement. The primary
objective of this study was to analyze the genetic diversity in A-genome diploid cotton species, G. herbaceum (A1) and G.␣arboreum (A2) by using microsatellite markers. Forty-one A-genome germplasm accessions were evaluated with 32 microsatellite loci.
Genetic similarities between A1 and A2 ranged from 0.62 to 0.86 with a mean of 0.70. Within each A-genome species similarities
ranged from 0.80 to 0.97 with a mean of 0.89 for A1 and from 0.82 to 0.98 with a mean of 0.89 for A2. A UPGMA tree and principal
coordinate analysis based on genetic similarity matrices showed distinct clusters consistent with the genomic groups. 相似文献
3.
F. Shan H. J. Clarke G. Yan J. A. Plummer K. H. M. Siddique 《Genetic Resources and Crop Evolution》2007,54(3):519-527
Wild annual Cicer gene pools contain valuable germplasm for chickpea improvement programs. Previous research showed that duplication might
exist in accessions collected from these gene pools, which would hinder chickpea breeding and related research. AFLP (amplified
fragment length polymorphism) markers were used to fingerprint the world collections of the primary and secondary gene pools
including C. reticulatum Lad., C. bijugum K.H. Rech., C. judaicum Boiss. and C. pinnatifidum Jaub. et Sp. Duplicates were detected in a total of 24 accessions in both the gene pools, highlighting the necessity to fingerprint
the germplasm. Genotypic difference was detected as gene pool specific, species specific and accession specific AFLP markers.
These were developed into fingerprinting keys for accession identification between and within species and gene pools. Use
of AFLP markers to detect duplicates and to identify accessions is a reliable method which will assist in the characterisation
and use of wild annual Cicer germplasm in chickpea improvement programs. We recommend the procedure presented in this paper as a standard approach for
the precise genetic identification and characterisation of future world collections of wild Cicer, to keep germplasm integrity and to benefit chickpea breeding and related research programs. 相似文献
4.
W. M. Kelman 《Genetic Resources and Crop Evolution》2006,53(8):1707-1713
Extensive germplasm resources are present in collections of Lotus corniculatus and L. uliginosus, two forage species that are valuable in situations where other legumes are not persistent. Naturalised populations in many
regions are the primary gene pool for genetic improvement of these species and interspecific hybrids are an important source
of variation for agronomic and forage quality traits. Although previous research has provided evidence that selection for
optimal levels of condensed tannins and herbage productivity are feasible breeding objectives, less is known about correlations
of condensed tannin with other parameters of nutritive value. A germplasm collection of 38 accessions in both species from
9 geographic regions was used as a data base to determine these correlations. Forage of each accession was sampled in two
successive years from a field site in south-eastern Australia and analysed for condensed tannin, in vitro digestible dry matter, nitrogen, acid detergent fibre and neutral detergent fibre. In both species condensed tannin was negatively
correlated with in vitro digestible dry matter and nitrogen. This result helped to identify potentially valuable accessions with low condensed tannin
(<4% of dry weight) and high in vitro digestible dry matter (>70%). One of these was an interspecific hybrid of L. uliginosus and L. corniculatus, confirming the view that interspecific hybridization would be a valuable avenue for improvement of agronomic and forage
quality characters in Lotus species. 相似文献
5.
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
6.
Alex Beharav Roi Ben-David Ivana Doležalová Aleš Lebeda 《Genetic Resources and Crop Evolution》2010,57(5):679-686
The wild lettuce, Lactuca aculeata Boiss. et Ky., is closely related and fully interfertile with cultivated lettuce, Lactuca sativa L. Altogether, 155 accessions of this wild species, which is rare conserved within the world’s germplasm collections, were
collected from 12 localities throughout northeastern Israel. Ten of these localities represent different sites across the
Golan Heights, while two, high-density populations were suprisingly found at the Hula Plain (first report of this species
in this region). Lactuca aculeata was recorded at various elevations (222–968 m a.s.l.) and habitats. The taxonomic status of 30 L. aculeata accessions was morphologically validated during ex situ seed regeneration of 31 random accessions representing all 12 localities. Characterization of 12 traits showed that the Israeli
populations of L. aculeata do not exhibit broad morphological variability, but more great levels of variation were obtained for developmental traits.
Relatively little variability was observed in the morphology of cauline leaves or in the distribution of anthocyanin pigmentation
in bracteae. In two cases, L. aculeata plants lacked trichomes in the inflorescence, a typical feature in the majority of plants. These unique collections of wild
lettuce may carry novel sources of genetic variation for a wide range of traits and, thus, should be of interest for careful
evaluation and exploitation in lettuce breeding. 相似文献
7.
Axel Diederichsen 《Genetic Resources and Crop Evolution》2007,54(3):661-678
An overview of ex situ collections of cultivated flax (Linum usitatissimum L.) and 53 other species of the genus Linum L. is presented. The names of 33 genebanks in 23 countries preserving Linum germplasm and the species preserved at these places are provided. World genebanks engage in ex situ preservation of about
48,000 accessions of cultivated flax (Linum usitatissimum). However, possibly only 10,000 accessions of these are unique. Of the ca. 200 species of the genus Linum, other than L. usitatissimum, 53 are reported to be represented in the world’s ex situ collections with a total of about 900 accessions. Of these, 279
accessions alone refer to the wild progenitor of cultivated flax, Linum bienne Mill. However, L. bienne from the region of origin of cultivated flax is rarely represented in genebank collections. References to publications describing
the techniques for ex situ conservation and the infraspecific variation of cultivated flax are made. It is suggested that
taxonomic species delimitation within the genus Linum is in need of clarification and that the variation in Linum species for ornamental use or use in breeding is investigated. 相似文献
8.
On the specific status of Gossypium lanceolatum Todaro 总被引:2,自引:0,他引:2
Summary
Gossypium lanceolatum comprises a group of laciniate-leaved commensal cottons from the Mexican states of Oaxaca and Guerrero. This geographically restricted, morphologically distinct group of perennial cottons has been considered conspecific with G. hirsutum, with which it is sympatric. In addition to its questionable specific status, G. lanceolatum has added importance because it represents the focal point of an hypothesis that New World tetraploid Gossypium have a polyphyletic origin—an hypothesis that conflicts with the more widely accepted view that New World tetraploid Gossypium have a monophyletic origin. To reassess the systematic and genetic relationships between G. lanceolatum and G. hirsutum, historical data were reconsidered in the context of recently published molecular marker based data. Chloroplast and nuclear DNA markers fail to discriminate G. lanceolatum from G. hirsutum, uniting both into a single phylogenetic lineage. A new analysis of allelic variability at 50 allozyme loci in 11 G. lanceolatum and 527 G. hirsutum accessions demonstrates that G. lanceolatum has no unique alleles relative to G. hirsutum. Genetic identity estimates were uniformly high (> 0.96) among G. lanceolatum and geographically adjacent, mainland Mesoamerican groups of G. hirsutum accessions. Multivariate analyses demonstrated that G. lanceolatum is genetically embedded within geographically adjacent populations of G. hirsutum. These data, in conjunction with the complete interfertility between the two taxa and previous evidence for conspecificity, lead to the conclusion that G. lanceolatum does not warrant specific status. Rather, it is more properly recognized as a locally developed, domesticated form of G. hirsutum, i.e., G. hirsutum race palmeri. 相似文献
9.
D. Minoo V. N. Jayakumar S. S. Veena J. Vimala A. Basha K. V. Saji K. Nirmal Babu K. V. Peter 《Genetic Resources and Crop Evolution》2008,55(3):459-470
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
10.
M. Costea D. M. Brenner F. J. Tardif Y. F. Tan M. Sun 《Genetic Resources and Crop Evolution》2006,53(8):1625-1633
The ‘Morelos’ accessions of Amaranthus from Mexico demonstrate taxonomic ambiguity at the basic morphologic level. The main cause is the enormous morphological
and genetic variation exhibited by the species in the genus. Although basic morphological criteria can be applied to herbarium
specimens or germplasm collections for quick taxonomic identification, the morphological data alone can be misleading. To
ascertain the taxonomic identity of the ‘Morelos’ accessions and their hypothesized species affiliation to Amaranthus caudatus or Amaranthus cruentus, we conducted a comparative analysis of phylogenetic relationships among these taxa/accessions using amplified fragment length
polymorphism (AFLP) and micromorphology methods. Based on AFLP data, all the controversial ‘Morelos’ accessions can be consistently
placed into a single A. cruentus species clade, which is clearly separated from the A. caudatus species clade. The AFLP-based phylogenetic relationship of ‘Morelos’ and delimitation of A. cruentus and A. caudatus are further supported by micromorphology, showing that the combination of these techniques can provide more reliable data
for germplasm identification than each method used alone. 相似文献
11.
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
12.
Effect of resolving medium and staining procedure on inter-simple-sequence-repeat (ISSR) patterns in cultivated flax germplasm 总被引:3,自引:0,他引:3
We compared ISSR patterns generated by three variants of resolving medium/staining procedure: agarose/ethidium bromide, polyacrylamide/silver staining, and polyacrylamide/SYBR Green I in order to prepare methodology for large-scale screening of genetic diversity in flax (Linum usitatissimum L.) germplasm collections. We found out that polyacrylamide/SYBR Green I system is the most suitable variant for large-scale characterization of genetic diversity within flax germplasm collections. 相似文献
13.
S. K. Malik R. Chaudhury O. P. Dhariwal Rajwant K. Kalia 《Genetic Resources and Crop Evolution》2006,53(7):1485-1493
Citrus indica and C. macroptera are the wild endangered species of Citrus occurring in northeastern India. Surveys were undertaken in this region for ascertaining distribution, studying variability
and for collection of germplasm of these two species. C. indica, an endemic species of this region, was collected from the Citrus Gene Sanctuary located in buffer zone of Nokrek Biosphere
Reserve in the Garo hills of Meghalaya. In addition, a putative natural hybrid of C. indica and C. limon was collected for the first time from the south Garo hills. C. macroptera had much wider distribution and was collected from Mizoram and Meghalaya states. In Jantia hills of Meghalaya, natural populations
of this species are in a highly threatened state. The two species were unevenly distributed all over the explored territory.
Morphological characterization of leaves, fruits and seeds indicated the presence of sizable variability within collected
accessions of these two Citrus species. Indigenous technical knowledge gathered on the use and socio-economic importance indicated commercial potential
for these two species in northeastern India. However, lack of cultivation of these species and clearing of forest cover at
an alarming rate has led to an urgent need to adopt complementary conservation strategies to safeguard these species and to
ensure their availability for future utilization. A major emphasis on developing methods for their propagation, multiplication
and regeneration in in situ and ex situ conditions is required. 相似文献
14.
R. G. Bennett M. H. Ryan T. D. Colmer D. Real 《Genetic Resources and Crop Evolution》2011,58(1):83-100
In the face of a drying climate, identification of perennial pasture species suited to low-rainfall agricultural areas is
needed. Effective prioritisation of putative pasture species may be possible through the use of desktop methods that are commonly
employed to investigate the effect of climate change on native plant populations or the weed risk potential of plants. Species
of Cullen Medik. native to Australia may be useful as perennial pasture legumes. It is not known, however, if species have adaptations
for growth in low rainfall regions like the wheatbelt of Western Australia (WA). We tested the hypothesis that some Cullen species would be adapted to the climate and soils of the low-rainfall wheatbelt of WA using an analysis of soils and climate
niche models of herbarium and germplasm records of 16 perennial, herbaceous and Australian Cullen species. We identified nine Cullen species that had some likely adaptation to the climate in the wheatbelt of WA, five of which (C. australasicum, C. cinereum, C. discolor, C. patens and C. tenax) had widespread adaptation to the climate and showed some adaptation to the soils of the wheatbelt of WA, making these priorities
for further evaluation as perennial pasture species. The methodology is useful to identify species with likely best adaptation
to low rainfall regions, generate expectations of where these may be most successful and to identify gaps in existing germplasm
collections. 相似文献
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16.
Sheji Mary N. V. Nair Pankaj Kumar Chaturvedi A. Selvi 《Genetic Resources and Crop Evolution》2006,53(6):1221-1231
Saccharum spontaneum L. a wild relative of sugarcane is the most variable and diverse among the Saccharum species. This species had been successfully exploited in sugarcane improvement programmes since 1915 and most of the present day commercial varieties are derivatives of interspecific hybrids involving S. spontaneum. The S. spontaneum germplasm available today in the World collections is diverse and represent different geographical groups. In the present investigation, an attempt was made to characterize 40 S. spontaneum clones collected from 4 different geographical areas in India using 20 random, 2 ISSR and 2 telomere primers. Of the 491 bands generated by these primers 83.9% were polymorphic. The genetic diversity estimated based on these markers was found to be moderate (48.9%). The pair-wise genetic distance between the accessions ranged from 29.8 to 60.0. The accessions from Arunachal Pradesh were found to be the most diverse, while Tamil Nadu accessions showed relatively less diversity. Diversity between Tamil Nadu and Kerala collections was found to be low, while the diversity between the Orissa group and the rest was found to be high. The collections from Mayurbanj and Cuttack regions of Orissa were found to be distinct. Arunachal Pradesh accessions, being more diverse, are a potential source for exploitation in sugarcane breeding programmes. 相似文献
17.
M. R. Naghavi M. J. Aghaei A. R. Taleei M. Omidi J. Mozafari M. E. Hassani 《Genetic Resources and Crop Evolution》2009,56(4):499-506
Simple sequence repeats (SSRs), highly dispersed nucleotide sequences in genomes, were used for germplasm analysis and estimation
of the genetic relationship of the D-genome among 52 accessions of T. aestivum (AABBDD), Ae. tauschii (DtDt), Ae. cylindrica (CCDcDc) and Ae. crassa (MMDcr1Dcr1), collected from 13 different sites in Iran. A set of 21 microsatellite primers, from various locations on the seven D-genome
chromosomes, revealed a high level of polymorphism. A total of 273 alleles were detected across all four species and the number
of alleles per each microsatellite marker varied from 3 to 27. The highest genetic diversity occurred in Ae. tauschii followed by Ae. crassa, and the genetic distance was the smallest between Ae. tauschii and Ae. cylindrica. Data obtained in this study supports the view that genetic variability in the D-genome of hexaploid wheat is less than in
Ae. tauschii. The highest number of unique alleles was observed within Ae. crassa accessions, indicating this species as a great potential source of novel genes for bread wheat improvement. Knowledge of
genetic diversity in Aegilops species provides different levels of information which is important in the management of germplasm resources. 相似文献
18.
This paper presents an effective method for prioritizing areas within a country for acquisition of germplasm of a crop gene
pool for ex situ conservation. The method was applied to the rare wild pepper species, Capsicum flexuosum Sendtn., in south-east Paraguay. A model to prioritize areas for collecting germplasm was constructed by combining (1) a
prediction of the species' geographic distribution based on the climate at previous collection points, (2) the distribution
of forest margins (the species' natural habitat) and (3) areas accessible by road. The model was then tested in the field
by visiting 20 sites having both high and low predicted probability of occurrence of C. flexuosum. Six new populations were found, representing a significant improvement over two previous collecting missions for the species
in the same region, undertaken without the use of GIS targeting. Using the most optimistic analysis of model performance,
C. flexuosum was found at five out of seven points predicted to harbour the species and not found at four of five points predicted not
to harbour the species. The model was then improved by the use of higher resolution climate surfaces. It is recommended that
future explorers use more recent and higher resolution satellite images to locate suitable habitats. The method is replicable
for different species in different geographic regions and is offered as a means of optimizing efficiency in financially constrained,
national plant genetic resources programs. 相似文献
19.
Riccardo Aversano Maria Raffaella Ercolano Luigi Frusciante Luigi Monti James M. Bradeen Gennaro Cristinzio Astolfo Zoina Nicola Greco Salvatore Vitale Domenico Carputo 《Genetic Resources and Crop Evolution》2007,54(8):1797-1806
Worldwide, a variety of pathogens negatively affect potato production, resulting in an estimated 22% annual yield reduction.
Wild Solanum species represent a unique gene pool where all the traits necessary to improve the cultivated potato can be found.
Therefore, breeding efforts for improved disease resistance and research aimed at characterizing wild germplasm have been
extensively made. In this paper, sources of resistance to Phytophthora
infestans, Erwinia carotovora subsp. carotovora, Fusarium solani and Globodera spp. have been investigated in several clones of two Solanum species originating from Central Mexico (S. bulbocastanum and S. cardiophyllum). Interestingly, we found sources of combined resistance to late blight and bacterial soft rot. This is an important finding
considering that the development of resistant potato varieties has been hindered by the scarcity of resistant germplasm. In
addition, we explored molecular differences within and between the two species generating AFLP fingerprints. By means of six
primer pair combinations, we found 13 and 16 putative species-specific AFLP markers for S. bulbocastanum and S. cardiophyllum, respectively, and a bounty of markers useful for mapping, MAS, and cloning purposes. The phenotypic and molecular information
associated to S. bulbocastanum and S. cardiophyllum for designing strategies of assisted selection are discussed. 相似文献
20.
Oryza granulata, an upland wild rice species, represents an unique germplasm for possessing abilities of tolerance to shade and drought,
immune to bacterial blight and resistance to brown planthopper. Although low degree of genetic variability has been revealed
within its populations, little genetic information at the species level is available in determining rational conservation
strategies. Here we used dominant DNA marker random amplified polymorphism DNA (RAPD) to assess the genetic variability among
23 accessions of O. granulata that collected from main distribution areas worldwide. Twenty decamer primers generated a total of 243 bands, with 83.5%
of them (203 bands) being polymorphic. Calculation of Shannon index of diversity revealed an average value of 0.42 ± 0.25,
indicating that O. granulata maintains a relatively high degree of genetic diversity on the species level. Analysis of genetic dissimilarity (GD) showed
that genetic differentiation occurred among studied accessions, which supports the feasibility of current ex situ conservation strategies. We also suggested that information based on population studies, which could be achieved by international
co-operation, is needed to conserve this widespread germplasm more effectively. 相似文献