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1.
Couepia is a genus distributed in tropical regions of America. The nut of some Couepia species is used as fresh fruit and oil source for local communities. Despite its critical situation of conservation and its economic potential, there is a lack of information on the genetic variability of Couepia species. This study examines AFLP variation among 40 accessions of Couepia collected in the Colombian Amazonian region, representing two species: Couepia dolichopoda and Couepia subcordata. The individuals were examined for 96 markers generated from four EcoRI/MseI primer pairs, with 80% polymorphism across all accessions studied. According to cluster analysis, 40 accessions were grouped into two major clusters, corresponding to the two species analyzed, except one case whose situation is discussed. In C. dolichopoda accessions, significant correlation between the clustering pattern and the geographical origin was detected; the extent of variation within and among its collect sites was examined by AMOVA. The knowledge about the genetic variability of the accessions examined contributes to development of Couepia conservational efforts.  相似文献   

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

3.
The present study was conducted to isolate and characterize rhizobial strains from root nodules of cultivated legumes, i.e. chickpea, mungbean, pea and siratro. Preliminary characterization of these isolates was done on the basis of plant infectivity test, acetylene reduction assay, C-source utilization, phosphate solubilization, phytohormones and polysaccharide production. The plant infectivity test and acetylene reduction assay showed effective root nodule formation by all the isolates on their respective hosts, except for chickpea isolate Ca-18 that failed to infect its original host. All strains showed homology to a typical Rhizobium strain on the basis of growth pattern, C-source utilization and polysaccharide production. The strain Ca-18 was characterized by its phosphate solubilization and indole acetic acid (IAA) production. The genetic relationship of the six rhizobial strains was carried out by random amplified polymorphic DNA (RAPD) including a reference strain of Bradyrhizobium japonicum TAL-102. Analysis conducted with 60 primers discriminated between the strains of Rhizobium and Bradyrhizobium in two different clusters. One of the primers, OPB-5, yielded a unique RAPD pattern for the six strains and well discriminated the non-nodulating chickpea isolate Ca-18 from all the other nodulating rhizobial strains. Isolate Ca-18 showed the least homology of 15% and 18% with Rhizobium and Bradyrhizobium, respectively, and was probably not a (Brady)rhizobium strain. Partial 16S rRNA gene sequence analysis for MN-S, TAL-102 and Ca-18 strains showed 97% homology between MN-S and TAL-102 strains, supporting the view that they were strains of B. japonicum species. The non-infective isolate Ca-18 was 67% different from the other two strains and probably was an Agrobacterium strain.  相似文献   

4.
This study aimed to investigate the effect of inoculation with plant growth-promoting Rhizobium and Pseudomonas species on NaCl-affected maize. Two cultivars of maize (cv. Agaiti 2002 and cv. Av 4001) selected on the basis of their yield potential were grown in pots outdoors under natural conditions during July. Microorganisms were applied at seedling stage and salt stress was induced 21 days after sowing and maintained up to 50% flowering after 120 days of stress. The salt treatment caused a detrimental effect on growth and development of plants. Co-inoculation resulted in some positive adaptative responses of maize plants under salinity. The salt tolerance from inoculation was generally mediated by decreases in electrolyte leakage and in osmotic potential, an increase in osmoregulant (proline) production, maintenance of relative water content of leaves, and selective uptake of K ions. Generally, the microbial strain acted synergistically. However, under unstressed conditions, Rhizobium was more effective than Pseudomonas but under salt stress the favorable effect was observed even if some exceptions were also observed. The maize cv. Agaiti 2002 appeared to be more responsive to inoculation and was relatively less tolerant to salt compared to that of cv. Av 4001.  相似文献   

5.
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   

6.
In a Robinia-pseudoacacia-dominated coastal forest in Tottori prefecture Japan, the growth and survival of Pinus thunbergii seedlings and the natural regeneration of P. thunbergii was disturbed by R. pseudoacacia. In order to improve the growth of P. thunbergii seedling in the Tottori sand dune, we tried to find a mycorrhiza helper bacteria (MHB) from P. thunbergii mycorrhizosphere in a Tottori sand dune. Two MHB, Ralstonia sp. and Bacillus subtilis, were selected from the nine bacterial species isolated from the mycorrhizosphere of P. thunbergii. The bacterial effect on the ectomycorrhizal fungus Suillus granulatus was investigated by confrontation assay and a microcosm experiment. The confrontation assay showed that Ralstonia sp. promoted the hyphal growth of S. granulatus. Moreover, the S. granulatusP. thunbergii symbiosis was significantly stimulated by Ralstonia sp. and B. subtilis. Ralstonia sp. and B. subtilis were regarded as MHB associated with P. thunbergii. This is the first report of Ralstonia sp. as an MHB.  相似文献   

7.
Genetic diversity and relationships within and among nine species of Coffea, one species of Psilanthus and the Piatã hybrid from the Coffee Germplasm Collection of Instituto Agronômico de Campinas (IAC), Brazil were assessed using RAPD markers. Genetic diversity and relationships were evaluated by proportion of polymorphic loci (P), Shannon’s genetic index (H′ and GST) and clustering analysis. The overall RAPD variation among all accessions was mostly partitioned between rather than within species. However, C. canephora and C. liberica showed a high genetic diversity within the species (\({\underline{\hbox{H}'}} \) sp = 0.414 and \({\underline{\hbox{H}'}} \) sp = 0.380, respectively) and this was highly structured (high \({\underline{\hbox{G}'}} \) ST). Genetic diversity from C. congensis and C. arabica was also structured, but with lower levels of genetic diversity (\({\underline{\hbox{H}'}} \) sp = 0.218 and \({\underline{\hbox{H}'}} \) sp = 0.126, respectively). The results were consistent with agronomic and molecular studies and demonstrated that the IAC Coffea Collection is representative of the phylogenetic structure observed in the genera. This study devises sampling strategies for coffee germplasm collections and provides genetic diversity parameters for future comparisons among them.  相似文献   

8.
Amplified fragment length polymorphism markers were used to assess the genetic relatedness between Dioscorea alata and nine other edible Dioscorea. These species include D. abyssinica Hoch., D. bulbifera L., D. cayenensis-rotundata Lamk. et Poir., D. esculenta Burk., D. nummularia Lam., D. pentaphylla L., D. persimilis Prain. et Burk., D. transversa Br. and D. trifida L. Four successive studies were conducted with emphasis on the genetic relationship within D. alata and among species of the Enantiophyllum section from Vanuatu. Study 1 was carried out to select a set of polymorphic primer pairs using 11 combinations and eight species belonging to five distinct sections. The four most polymorphic primer pairs were used in study 2 among six species of the Enantiophyllum section. Study 3 focussed mainly on the genetic relationship among 83 accessions of D. alata, mostly from Vanuatu (78 acc.) but also from Benin, Guadeloupe, New Caledonia and Vietnam. The ploidy level of 53 accessions was determined and results indicated the presence of tetraploid, hexaploid and octoploid cultivars. Study 4, included 35 accessions of D. alata, D. nummularia and D. transversa and was conducted using two primer pairs to verify the taxonomical identity of the cultivars `langlang', `maro' and `netsar' from Vanuatu. The overall results indicated that each accession can be fingerprinted uniquely with AFLP. D. alata is an heterogeneous species which shares a common genetic background with D. nummularia and `langlang', `maro' and `netsar'. UPGMA cluster analysis revealed the existence of three major groups of genotypes within D. alata, each assembling accessions from distant geographical origins and different ploidy levels. The analysis also revealed that `langlang', `maro' and `netsar' clustered together with the cultivar `wael' (D. transversa) from New Caledonia. Results are discussed in the paper.  相似文献   

9.
A fertile amphidiploid × Brassicoraphanus (RRCC, 2n = 36) between Raphanus sativus cv. HQ-04 (2n = 18, RR) and Brassica alboglabra Bailey (2n = 18, CC) was synthesized and successive selections for seed fertility were made from F4 to F10. F10 plants exhibited good fertility with 14.9 seeds per siliqua and 32.3 g seeds per plant. Cytological observation revealed that frequent secondary pairing occurred among 3 chromosome pairs in pollen mother cells of plants (F4) with lower fertility, but not of plants with high fertility (F10). GISH analysis indicated that these F10 plants included the expected 18 chromosomes from R. sativus and B. alboglabra, respectively, but they lost approximately 27.6% R. sativus and 35.6% B. alboglabra AFLP (amplified fragment length polymorphism) bands. The crossability of the Raphanobrassica with R. sativus and 5 Brassica species (13 cultivars) were investigated. Seeds or F1 seedlings were easy to be produced from crosses × Brassicoraphanus × R. sativus, and B. napus, B. juncea and B. carinata × Brassicoraphanus. Fewer seeds or seedlings were obtained from crosses × Brassicoraphanus × B. napus, B. juncea and B. carinata. However, few seeds were harvested in the reciprocals of × Brassicoraphanus with B. rapa and B. oleracea. The possible cause of fertility improvements and the potential of the present × Brassicoraphanus for breeding were discussed.  相似文献   

10.
Grains of 80 accessions of nine species of wild Triticum and Aegilops along with 15 semi-dwarf cultivars of bread and durum wheat grown over 2 years at Indian Institute of Technology, Roorkee, were analyzed for grain iron and zinc content. The bread and durum cultivars had very low content and little variability for both of these micronutrients. The related non-progenitor wild species with S, U and M genomes showed up to 3–4 folds higher iron and zinc content in their grains as compared to bread and durum wheat. For confirmation, two Ae. kotschyi Boiss. accessions were analyzed after ashing and were found to have more than 30% higher grain ash content than the wheat cultivars containing more than 75% higher iron and 60% higher zinc than that of wheat. There were highly significant differences for iron and zinc contents among various cultivars and wild relatives over both the years with very high broad sense heritability. There was a significantly high positive correlation between flag leaf iron and grain iron (r = 0.82) and flag leaf zinc and grain zinc (r = 0.92) content of the selected donors suggesting that the leaf analysis could be used for early selection for high iron and zinc content. ‘Chinese Spring’ (Ph I ) was used for inducing homoeologous chromosome pairing between Aegilops and wheat genomes and transferring these useful traits from the wild species to the elite wheat cultivars. A majority of the interspecific hybrids had higher leaf iron and zinc content than their wheat parents and equivalent or higher content than their Aegilops parents suggesting that the parental Aegilops donors possess a more efficient system for uptake and translocation of the micronutrients which could ultimately be utilized for wheat grain biofortification. Partially fertile to sterile BC1 derivatives with variable chromosomes of Aegilops species had also higher leaf iron and zinc content confirming the possibility of transfer of required variability. Some of the fertile BC1F3 and BC2F2 derivatives had as high grain ash and grain ash iron and zinc content as that of the donor Aegilops parent. Further work on backcrossing, selfing, selection of fertile derivatives, leaf and grain analyses for iron and zinc for developing biofortified bread and durum wheat cultivars is in progress. Nidhi Rawat, Vijay K. Tiwari, and Neelam Singh have contributed equally to the work.  相似文献   

11.
Root colonization and mitigation of NaCl stress on wheat seedlings were studied by inoculating seeds with Azospirillum lipoferum JA4ngfp15 tagged with the green fluorescent protein gene (gfp). Colonization of wheat roots under 80 and 160 mM NaCl stress was similar to root colonization with this bacterial species under non-saline conditions, that is, single cells and small aggregates were mainly located in the root hair zone. These salt concentrations had significant inhibitory effects on development of seedlings, but not on growth in culture of gfp-A. lipoferum JA4ngfp15. Reduced plant growth (height and dry weight of leaves and roots) under continuous irrigation with 160 mM NaCl was ameliorated by bacterial inoculation with gfp-A. lipoferum JA4ngfp15. Inoculation of plants subjected to continuous irrigation with 80 mM NaCl or to a single application of either NaCl concentration (80 or 160 mM NaCl) did not mitigate salt stress. This study indicates that, under high NaCl concentration, inoculation with modified A. lipoferum reduced the deleterious effects of NaCl; colonization patterns on roots were unaffected and the genetic marker did not induce undesirable effects on the interaction between the bacterium and the plants.  相似文献   

12.
Diversity analysis was performed among 39 cultivated lentil (Lens culinaris Medik.) accessions of Central Asia and Caucasian origin using five highly polymorphic microsatellite markers. A total of 33 alleles determined ranging from 3 to 8 per locus. Estimated gene diversity value for 33 loci was 0.66. Genetic similarity indices among 39 accessions ranged from 0.24 to 1.0. Cluster analysis using the unweighted pair group method with arithmetic mean method classified accessions into six major groups at 0.5 similarity coefficient. More than half accessions from Tajikistan formed large cluster. On the other hand, a few accessions from each country showed unique genotypes. Overall, most of the accessions, except ones with closely related origin, were distinguished by the present high quality DNA fingerprinting. This molecular diversity information gives important basis for conservation strategy in gene bank and exotic germplasm introduction in breeding programs in Central Asia and Caucasian countries.  相似文献   

13.
Neglected and underutilized species often play a vital role in securing food and livestock feed, income generation and energy needs of rural populations. In spite of their great potential little attention has been given to these species. This increases the possibility of genetic erosion which would further restrict the survival strategies of people in rural areas. Ziziphus spina-christi is a plant species that has edible fruits and a number of other beneficial applications that include the use of leaves as fodder, branches for fencing, wood as fuel, for construction and furniture making, and the utilization of different parts e.g. Fruits, leaves, roots and bark in folk medicine. Moreover, the plant is adapted to dry and hot climates which make it suitable for cultivation in an environment characterized by increasing degradation of land and water resources. Lack of research in Z. spina-christi hinders its successful improvement and promotion. Therefore, studies are needed to fully exploit this species. This article aims at summarizing information on different aspects of Z. spina-christi to stimulate interest in this crop which is of importance in Sudan and other countries of the semi-arid tropics.
Amina Sirag SaiedEmail:
  相似文献   

14.
The classification and phylogeny of the species belonging to Solanum section Lycopersicon is a complex issue that has not yet reached a widely accepted consensus. These species diverged recently, are still closely related and, in some cases, are still even capable of interspecific hybridization, thereby blurring the difference between intra- and interspecific variation. To help resolve these issues, in the present study, several accessions covering the natural range for each species were used. In addition, to avoid biases due to the molecular method employed, both AFLP markers and two nuclear-gene sequences, CT179 and CT66, were used to characterize the plant materials. The data obtained suggest a classification similar to those previously proposed by other authors, although with some significant changes. Twelve species were recognized as distinct based on this dataset. According to the data presented, the recently proposed species, S. corneliomulleri, is indistinguishable from S. peruvianum s.str. In addition, both the sequence and the AFLP trees suggest that S. arcanum could represent a complex of populations composed of two cryptic species. With regard to phylogenetic relationships among these species, some clear groups were found: the Lycopersicon group formed by S. pimpinellifolium, S. lycopersicum, S. cheesmaniae and S. galapagense; the Arcanum group constituted by S. chmielewskii, S. neorickii, S. arcanum and S. huaylasense; and the Eriopersicon group made up of S. peruvianum and S. chilense. Solanum pennellii and S. habrochaites are not included in any group, but are the closest to the S. lycopersicoides outgroup. Jose Blanca and Fernando Nuez have contributed equally to this work and should be regarded as co-second authors.  相似文献   

15.
Lotus (Nelumbo nucifera Gaertn. ssp. nucifera), one of 12 aquatic species used as vegetable, has been cultivated for more than 2,000 years, and now has been widely cultivated in almost all provinces in China. The largest area under cultivation of lotus is located in the regions surrounding mid-down Yangtse River, including Hubei, Jiangsu, Zhejiang, Anhui, Jiangxi and Hunan provinces. According to different purposes or morphological differences, the Chinese lotus (N. nucifera ssp. nucifera) is usually classified into three types: rhizome lotus, seed lotus and flower lotus. Rhizome lotus is mainly cultivated in Hubei, Jiangsu, Anhui and Zhejiang provinces; Seed lotus in Jiangxi, Fujian and Hunan, and flower lotus in Wuhan, Hubei province, and Beijing. Up to the year 2002, a total of 572 lotus accessions (including landraces, cultivars and breeding lines) were conserved in National Garden of Aquatic Vegetable, Wuhan, Hubei province, including those collections from 153 counties in 18 provinces, and lines bred by breeders. Out of these accessions, 310 were rhizome lotus which contains 201 landraces and 109 breeding lines; 229 were flower lotus including 172 cultivars and 57 breeding lines; and the rest 33 were seed lotus with 18 cultivars.  相似文献   

16.
Calamintha nepeta and Micromeria thymifolia have been traditionally used in the Mediterranean area as condiments and medicinal plants for a long time. Whereas in parts of Italy C. nepeta (special recipes have been developed in Lazio and Tuscany) is also an established garden plant showing different evolutionary products and their interaction among each other and the wild progenitor, M. thymifolia is being developed into a new crop plant. Both plants and their uses are described with regard to Italy. There is a marked tendency to broaden the use of condiments and spices which results in new crop plants which have to be documented and elaborated in further studies. Many species of Labiatae are predisposed to use by man and new items can be found even in areas which have to be considered as well studied.  相似文献   

17.
The genus Aegilops L. is a very important genetic resource for the breeding of bread wheat Triticum aestivum. Therefore, an accurate and easy identification of Aegilops species is required. Traditionally, identification of Aegilops species has relied heavily on morphological characters. These characters, however, are either not variable enough among Aegilops species or too plastic to be used for identification at the species level. Molecular markers that are more stable within species, therefore, could be the alternative strategy towards an accurate identification. Since the chloroplast DNA has a lower level of evolution compared to the nuclear genome, an attempt was made in this study to investigate polymorphism in the chloroplast DNA among 21 Aegilops species (including Ae. mutica that is now known as Amblyopyrum muticum) and between the latter and T. aestivum to generate markers for the diagnosis of all targeted species. Cleaved amplified polymorphic sequence (CAPS) applied on 22 coding and non-coding chloroplast regions using 80 endonucleases and sequencing of two of those regions revealed little polymorphism between T. aestivum and the various Aegilops species examined and to a less extent was the variation among Aegilops species. Polymorphism observed among species analysed allowed the discrimination of T. aestivum and 12 Aegilops species.  相似文献   

18.
RAPD markers were applied to subterranean clover aiming at: (i) assessing the genetic relationships among the subspecies subterraneum L., brachycalycinum Katzn. et Morley, yanninicum Katzn. et Morley, as their taxonomic status is still debated; (ii) verifying the adoption of RAPDs to supplement the common morphological markers used for cultivar identification and protection; (iii) assessing the possible genetic diversity in relation to the geographic origin. Eight primers were selected for genetic analysis of 18 genotypes: 10 subsp. yanninicum (five from Greece and five from Sardinia), six subsp. subterraneum (forming three pairs, each one difficult to distinguish by morphological markers), and two subsp. brachycalycinum. Cluster analysis, performed on the Jaccards coefficients of association computed across the eight primers, formed three groups of genotypes, corresponding to the three subspecies. The results supported at the DNA level previous inferences, made at cytological, karyological, and isoenzymatic levels, on the ongoing speciation process within the subterranean clover complex, although not warranting yet the full species rank to the three forms. The genotypes of subsp. yanninicum were genetically closer to those of subsp. subterraneum than either group was to the subsp. brachycalycinum genotypes. Within the subsp. yanninicum cluster, the Sardinian genotypes appeared fairly distinct from those from Greece, suggesting a possible, independent evolution going on in different centres of diversity of this subspecies. In two pairs of subsp. subterraneum genotypes, the members could be unequivocally distinguished, thus supporting the role of RAPD fingerprinting in cultivar identification. In the third pair, the two genotypes appeared to be the same, inadvertently duplicated within the germplasm collection.  相似文献   

19.
20.
Emmer wheat (Triticum dicoccon Schrank, 2n = 4x = 28) consists in a hulled wheat; its cultivation has been drastically reduced during the last century as a consequence of its low yield. Recently, its agronomic and nutritive values, as well as the increase of popularity of organic agriculture, have led to a renewed interest making its cultivation economically viable in the marginal lands with an increase of the cultivated areas. In Italy, it mainly survives in few marginal lands of central and southern Italy, where local varieties, adapted to the natural environment from where they originate, are used; moreover, some selected lines have also been developed. In the present work, agro-morphological and qualitative traits, together with molecular analyses of 20 emmer accessions consisting of Italian landraces, breeding lines, and cultivars, were performed. The field experiments were conducted for two consecutive years (2001/2002–2002/2003) in two locations: Viterbo in central Italy, and Foggia in south Italy. The analyzed emmer wheat accessions showed a good amount of genetic variability for both evaluated agro-morphological and molecular traits. This study illustrates an increase in earliness, GY, TW, TKW, and YI going from landraces, breeding lines to cultivars, while the variability does not change proportionally.  相似文献   

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