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1.
The domestication of cultivated flax (Linum usitatissimum L. subsp.usitatissimum) is briefly discussed. Using data documented as a matter of routine in genebank work, 63 accessions of cultivated flax from the flax germplasm collection of the Gatersleben Genebank are compared with 73 accessions of its wild progenitor pale flax (subsp.angustifolium (Huds.) Thell.), which have been observed in systematic field trials. Range of variation, genetically based variation, heritability and correlation of several characters are considered, especially with respect to the influence of domestication. Cultivated flax shows higher variation in the characters of generative plant parts, while pale flax varies more in the vegetative parts of the plant. The character correlations are similar in both subspecies. Of the 29 characters studied in pale flax the parameters describing tillering, height of plant, weight of seeds, width of petals and width of leaves are especially suitable for distinguishing between different accessions. In spite of the high heritabilities of most of the characters, the influence of the environment is significant in most cases.  相似文献   

2.
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3.
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   

4.
Crop wild relatives are invaluable sources of novel genes for crop improvement and adaptation to changing environments. We assessed phylogenetic relationships among 29 Linum accessions representing 16 species, including cultivated flax and its progenitor pale flax, based on four non-coding regions of chloroplast DNA sequences. We obtained a cpDNA network showing that these 16 Linum species are appropriately connected based on previously defined taxonomic sections; these connections reflect the same evolutionary pathways as determined from earlier morphological and cytological data. These relationships also support an earlier hypothesis that cultivated flax is probably descended from a single domestication of pale flax plants, apparently for oil usage. The detailed species network not only is significant for understanding evolutionary relationships of Linum species, but also useful for classifying exotic gene pools of cultivated flax as a part of the ongoing exploration of new genetic diversity for flax improvement.  相似文献   

5.
RAPD analysis was applied to five species belonging to the genusLathyrus (Fabaceae): L.sativus, L.cicera, L.ochrus, L.sylvestris and L.latifolius. All the species under study belong to thesection Lathyrus except L.ochrus which is in section Clymenum.Nine populations representing these species were used and ten random10-mer primers were sampled. A total of 129 amplification products,ranging in size from 0.3 to 3 Kb, were generated. Partitioning ofvariation was studied using the AMOVA technique. The genetic variation proved tobe nearly equally distributed among species and among populations withinspecies. A similar approach was carried out to distinguish populations, whichproved to be efficient. The between population dissimilarities were calculatedand a dendrogram of genetic relationships was drawn. The RAPDs obtained weresufficient to distinguish between the two accessions of a species and toseparate these accessions by clustering them according to species. A highgenetic similarity between the populations of L.sylvestris and L.latifolius was established. A similar result is also shownfor the populations of L. sativus andL. cicera.  相似文献   

6.
The present study was performed to investigate genetic diversity of Kenyan landraces of the white-flowered gourd (Lagenaria siceraria), which exhibits tremendous morphological variation. RAPD analyses were performed on 53 landraces of the cultivated species L. siceraria and 42 accessions of three wild species (40 L. sphaerica, 1 L. abyssinica, and 1 L. breviflora). A total of 432 polymorphic bands were detected using 54 primers. The four species were clearly differentiated from one another. Intra-specific variations were investigated with L. siceraria and its wild relative L. sphaerica. Landraces of the cultivated species collected from different ethnic communities or regions were differentiated. Morphological variations were not associated with RAPD variations. Bitter landraces collected in Maasai communities showed two specific RAPD bands. In the wild species, accessions collected from the eastern and western sides of the Great Rift Valley were genetically differentiated from each other. In both species, genetic and geographical distance matrices computed among all pairs of accessions were significantly correlated, implying that the observed geographical variation can be explained by the 'Isolation by distance model'. Progeny plants derived from a common mother in L. siceraria showed a low level of segregation in RAPD pattern, suggesting that collected landraces are cultivated, maintaining their inherent traits although they are monoecious and insect-pollinated, whereas the wild relative L. sphaerica showed a higher level of segregation. The morphological diversity observed among landraces of L. siceraria is the result of human selection and their genetic identities are maintained by inbreeding probably resulting from frequent self-pollination.  相似文献   

7.
The cultivated peanut (Arachis hypogaea L.) is an allotetraploid, with two types of genomes, classified as AA and BB, according to cytogenetic characters. Similar genomes to those of A. hypogaea are found in the wild diploid species of section Arachis, which is one of the nine Arachis sections. The wild species have resistances to pests and diseases that affect the cultivated peanut and are a potential source of genes to increase the resistance levels in peanut. The aim of this study was to analyze the genetic variability within AA and BB genome species and to evaluate how they are related to each other and to A. hypogaea, using RAPD markers. Eighty-seven polymorphic bands amplified by ten 10-mer primers were analyzed. The species were divided into two major groups, and the AA and the BB genome species were, in general, separated from each other. The results showed that high variation is available within species that have genomes similar to the AA and the BB genomes of A. hypogaea.  相似文献   

8.
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   

9.
The diversity of pale flax (Linum bienne Mill.) as the progenitor of cultivated flax (L. usitatissimum L.) has not been well documented and the domestication syndromes in cultivated flax are poorly understood. An attempt was made to characterize 34 pale flax accessions and six cultivated flax accessions collected during 2007 summer in Turkey. A total of 12 quantitative and 7 qualitative characters covering vegetative and generative plant parts, including phenological traits, were assessed. The occurrence of yellow anthers well known in cultivated flax is reported for the first time in pale flax. Pale flax displayed larger variation in vegetative plant parts and growth habit than the cultivated flax and more heterogeneity within accessions. Within pale flax, a higher degree of variation was observed in many generative parts such as the flower characters than in the capsule and seed characters. Based on the assayed characters, the pale flax from Turkey was grouped into three clusters and these clusters were associated with site elevation and longitude, further confirming local genetic differentiation in pale flax from Turkey. These findings are significant for further studies of flax domestication history and useful for further exploitation of wild flax in genetic improvement of cultivated flax.  相似文献   

10.
A RAPD analysis was conducted to clearify the mode of evolution of barley in the western Mediterranean basin. Twenty-nine barley accessions (Hordeum vulgare) and 13 populations of the wild progenitor (H. v. subsp. spontaneum) together with two outgroup species were analysed with seven RAPD primers, resulting in 101 polymorphic amplified fragments. Phenetic and cladistic analyses of the RAPD data resulted in trees indicating a monophyletic origin of cultivated barley, thus making a secondary domestication in Morocco unlikely. In Morocco spontaneous back mutation to wild type and crossing between wild barley (introduced from the E Mediterranean) and cultivated lines occurred, which gave rise to the local weedy forms of barley.  相似文献   

11.
Cultivated lentil (Lens culinaris Medik. subsp. culinaris) has a relatively narrow genetic base and many commercial cultivars are susceptible to ascochyta blight caused by Ascochyta lentis Vassilievsky. A total of 375 accessions of six wild species of lentil received from ICARDA and 18 cultivated genotypes were screened for resistance to A. lentis under both field and greenhouse conditions in Saskatoon, Canada. A mixture of three monoconidial isolates of A. lentis was used as an inoculum and the level of infection rated using the Horsfall-Barratt scale (0–11). Accessions with resistance to A. lentis were observed in all wild species except for L. culinaris subsp. tomentosa (Ladiz.) Ferguson et al. showing no resistant accessions. Several consistently resistant accessions were found among entries of L. ervoides (Brign.) Grande and L. nigricans, (M. Bieb.) Godr., both of which belong to the secondary gene pool and a few in L. culinaris subsp. orientalis (Boiss.) Ponert and L. culinaris subsp. odemensis (Ladiz.) Ferguson et al. belonging to the primary gene pool. Some accessions of L. ervoides exhibited lower disease ratings and AUDPC values than the resistant control cv. ‘Indianhead.’ Thirteen accessions, previously reported as resistant to Syrian isolates of A. lentis were also resistant to the Canadian isolates; some also had resistance to anthracnose. The highest frequency of resistance was found in accessions of L. ervoides which originated from Syria and Turkey. These wild accessions represent a useful and untapped source for improving disease resistance in lentil.  相似文献   

12.
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   

13.
Isozyme variation and phylogenetic relationships between ten annual andperennial Lathyrus species: L.aphaca, L.articulatus, L.cicera, L.hirsutus, L.latifolius, L.nissolia, L.odoratus, L.ochrus, L.sativus and L.sylvestris were studied. Four enzyme systems,leucine-amino-peptidase (LAP), 6-phosphogluconatedeshydrogenase (6-PGD), glutamateoxalo-acetate transaminase (GOT) and phosphoglucoisomerase(PGI) were analyzed, using gel electrophoresis. Fivepolymorphic loci were detected and eleven alleles were identified at these loci.Zymogram data revealed that almost all-present species studied exhibited isozymepolymorphism. L. latifolius andL. sylvestris maintain high levels ofisozyme diversity, which is probably associated with the perenniality of thesetwo species and their predominantly outcrossing reproduction system. Incontrast, the low level of genetic diversity observed in other species isattributed to their breeding systems. These species are annuals and have higherproportions of selfing. The distribution of genetic variation within and amongspecies showed large genetic differences between the analysed species.PGD-1 andPGD-2 loci contributed the most to thedistinction between species. GOT-2,LAP-1 and PGI-1loci contributed to the distinction within species. The low level of gene flowrevealed could be partly related to the high level of autogamy in the majorityof species. The regroupement of species revealed by Nei's genetic similarityagrees only in parte with Kupicha's classification based on morphologicalcharacters. Thus, these isozymic markers are important in germplasm collectionand conservation.  相似文献   

14.
The genus Arachis is endemic to South America and comprises 80 species, 69 of which have already been described and eleven not yet published. The genus includes the cultivated peanut (A. hypogaea) and several forage species, the most important ones being A. glabrata and A. pintoi. Accessions of section Rhizomatosae, including three tetraploid species 2n = 4x = 40 (A. glabrata, A. pseudovillosa and A. nitida nom. nud.) and one diploid species 2n = 2x = 20 (A. burkartii), were evaluated using RAPD markers to assay genetic variability within and among species. The ten random primers used yielded a total of 113 polymorphic bands. The data were scored as the presence or absence of each band in each sample. A distance matrix and dendrogram were obtained using Link's coefficient and the neighbor-joining method. Most accessions analyzed grouped into two major clusters: the first comprised most accessions of A. glabrata and accessions of A. nitida, and the second cluster comprised accessions of A. burkartii. Arachis pseudovillosa and a few accessions of A. glabrata and A. nitida were placed between these major clusters. The diploid and tetraploid species were grouped quite separately, suggesting that the tetraploids did not originate from the diploid species analyzed.  相似文献   

15.
RAPD variation in wild, weedy and cultivated azuki beans in Asia   总被引：12，自引：0，他引：12  
RAPD (Random Amplified Polymorphic DNA) variation was assessed in 42 accessions of azuki bean (Vigna angularis) including wild, weedy and cultivated races and in three accessions of two related species used as outgroups. A much lower level of genetic variation was observed in cultivated and weedy azuki beans compared to wild azuki bean. Wild azuki bean (V. angularis var. nipponensis) has relatively high genetic variation in subtropical highlands of Asia compared to the Far East. Although cultivated azuki bean has low RAPD variation, accessions from subtropical highlands and Southeast Asia showed different RAPD features compared to those of the Far East. It is hypothesized that the cultivated azuki bean has been derived from wild azuki bean in the Far East; the high variation in wild azuki bean has been created through its natural dissemination; and the relatively low variation in cultivated azuki bean has come about through human dissemination after genetic bottleneck reduced by domestication. In addition, high genetic diversity in wild azuki bean in subtropical highlands of Asia is regarded as an important genetic resource in azuki improvement.  相似文献   

16.
Soybean (Glycine max L.) is the most widely cultivated crop in the world and an important commodity. Besides its main role in human nutrition, this grain is also used in animal feed and production of biofuels, among other purposes. Due to these factors, soybean became important in the global economy and is the most exported agricultural product from Brazil. Fungal diseases are among the limiting factors on soybean production; sudden death syndrome, caused by Fusarium spp., has been responsible for severe losses on this crop in Brazil. Four species of Fusarium can be considered causal pathogens: F. brasiliense, F. crassistipitatum, F. tucumaniae, and F. virguliforme. The Fusarium spp. isolates characterized in this work were collected in different soybean-producing regions in Brazil. The genetic variability of these isolates was determined through the random amplified polymorphic DNA (RAPD) technique. Disease severity was evaluated on moderately resistant and susceptible soybean cultivars in greenhouse trials. RAPD analysis demonstrated a great genetic diversity among the isolates and a clear tendency to split into two main species groups, F. tucumaniae and F. brasiliense, both prevalent in Brazil. The disease severity experiments, in which soybean plants were artificially inoculated, have shown that all isolates caused significant damage to the seedling root system. In fact, the genetic diversity of isolates does not correlate with disease severity, and also does not correlate with geographic distribution.  相似文献   

17.
Flax (Linum usitatissimum L.) is the earliest oil and fibre crop, but little is known about its domestication process. Attempt was made here to assess genetic relationships of 63 Linum accessions representing seven typical groups of cultivated flax and its wild progenitor, pale flax (Linum bienne Mill.), by using 49 informative expressed sequence tag-derived simple sequence repeat (EST-SSR) primer pairs. The seven groups were pale flax from Turkey, pale flax from other countries, and five groups of cultivated flax (landrace, fibre, oil, winter, and dehiscent). From these 63 samples, 366 polymorphic bands were detected, which likely represented 79 loci. These polymorphic bands had frequencies that ranged from 0.016 to 0.984 and averaged 0.284. Group-specific EST-SSR variation (Fst values) ranged from 0.339 to 0.373 and averaged 0.349 and pairwise group EST-SSR variation ranged from 0.067 to 0.507. A neighbor-joining clustering of these seven groups revealed that dehiscent flax clustered most closely to its wild progenitor, pale flax, followed by oil flax and fibre flax. Winter flax clustered most closely to oil flax and less to pale flax. These clustering patterns were essentially the same when individual samples were analyzed via neighbor-joining. These findings strongly suggest that capsular dehiscence was among the first flax traits modified by human after initial domestication, reflecting the importance that reducing capsular dehiscence likely played in early flax domestication.  相似文献   

18.
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   

19.
Genetic diversity of seven cultivated populations of Codonopsis pilosula Nannf. from Longxi County, Gansu Province of China was estimated using randomly amplified polymorphic DNA (RAPD) markers. The 17 selected RAPD primers amplified 205 polymorphic bands out of a total of 235 (87.2%). Nei’s gene-diversity statistics and population differentiation parameters based on AMOVA analysis indicated that the cultivated C. pilosula populations remained a high level of genetic diversity with Hs = 0.299 and I = 0.450. A greater proportion of genetic diversity was found within (77%) rather than among (23%) the populations. In addition, we also detected that populations from different altitudes had a considerable genetic differentiation after 40 years of cultivation at the same site. Populations from higher altitude had lower genetic diversity than those from lower altitude. Our results suggested that irregular and sparse cultivation practices, i.e., random collecting, preserving, and planting seeds of the medicinal species without deliberate selection, might be an efficient way to conserve genetic resources of medicinal plants, in addition to their effective uses.  相似文献   

20.
Allozyme polymorphism at seven loci (TPI, G6PD-2,IDH-1, SKD-2, MDH-1, GOT-1, andGOT-2) was employed to detect the level of geneticdiversity in C.alismatifolia populations from both cultivatedand wild habitats in Thailand. High diversity was observed in allpopulations with relatively lower values in cultivated populations.Percentage of polymorphic loci (P)varied from 85.7–100% in cultivated populations comparedwith 100% in all natural populations. Allele number per locus(A L) was 3.14 in cultivatedpopulations, and from 2.86–4 in natural populations. Allelenumber per polymorphic locus(A P) of cultivated andnatural populations ranged from 3.14–3.5 and 2.86–4,respectively. Genetic diversity within populations(H S) varied from0.586–0.611 in cultivated and from 0.621–0.653 in naturalpopulations. The genetic identity(I SP) for the species was0.833. The cultivated populations yielded higher value of geneticidentity with highland populations(I C /H =0.776) than with the lowland ones(I C /L =0.754). The analysis of genetic similarities with theNeighbor-Joining algorithm results in the separation ofcultivated populations from all wild populations. One highlandpopulation from the tourist spot, H2, was placed in a separatecluster between the cultivated and other wild populations. It isconsidered as the possible origin of the cultivatedpopulations.  相似文献   

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