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  • Genetic resources  (3)
  • Allium  (2)
  • RFLP  (2)
  • 1
    Electronic Resource
    Electronic Resource
    Springer
    Theoretical and applied genetics 100 (2000), S. 607-613 
    ISSN: 1432-2242
    Keywords: Key words AFLP ; Biodiversity ; Genetic maps ; Genetic resources ; Rice
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract  Genetic diversity within populations of organisms and species is commonly measured using molecular-marker data. It has been claimed that more reliable diversity measurements can be obtained using selected genetically mapped markers to ensure that all regions of the genome are represented in the data sets employed. However, this has not been tested. In the present study, using rice (Oryza sativa L.) as a model species, we have shown that the use of unmapped AFLP markers reveals a pattern of diversity that is very similar to that obtained using a range of other marker types and which reflects the known crossability groups within this species. In contrast, we show that use of mapped-marker data can, in some cases, result in highly misleading patterns of diversity; the results obtained are critically related to the choice ofparents used in the cross from which the mapping population was produced. For diversity analyses, we propose that it is appropriate to use unmapped markers provided that the marker-type has been shown to have a wide distribution over the genome.
    Type of Medium: Electronic Resource
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  • 2
    ISSN: 1432-2242
    Keywords: Beta vulgaris L. ; Isozyme phenotype ; Phenotypic polymorphism ; Allele frequency ; Genetic resources
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Thirteen enzymes (MDH, SDH, LAP, PGM, PX, IDH, GPI, 6PGD, APH, GOT, GDH, ME and SOD) of 3 cultivated beet (B. vulgaris L.) gene pools, comprising 12 accessions of fodder beet, 11 of old multigerm sugar beet and 10 of modern monogerm sugar beet, were investigated using horizontal starch gel electrophoresis. Eleven accessions of primitive or wild B. vulgaris were also included for the comparison of isozymes. Variation in isozyme phenotypes was investigated to detect diversity in the three cultivated forms of beet. Phenotypic variation was observed in all except ME and SOD, which were monomorphic. A high degree of phenotypic polymorphism (Pj) was found in GDH, PGM, IDH, APH and MDH. Differences in phenotypic polymorphism in MDH, GPI and PX were recognized between fodder beet and both sugar beet groups. Average polymorphism for 13 enzymes in both sugar beets was significantly higher than that in fodder beet. For 13 enzymes, the existence of high isozyme diversity in both sugar beet gene pools was revealed. Allele frequencies in 13 alleles of five enzyme-coding loci, Lap, Px-1, Aph-1, Got-2 and Gdh-2, were investigated. New alleles, Px-1 1 and Got-2 1, were found in fodder beet accessions. No significant differences of average allele frequencies of five loci between fodder beet and both sugar beets were recognized. Several unique alleles and different isozyme phenotypes were observed in the accessions of B. vulgaris ssp. macrocarpa and ssp. adanensis. Future utilization of cultivated beet gene pools for sugar beet breeding is discussed from the viewpoint of genetic resources.
    Type of Medium: Electronic Resource
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  • 3
    ISSN: 1432-2242
    Keywords: Sugar beet ; Beta nana ; Beta vulgaris ; RFLP
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary cDNA probes have been used to assess genetic variation in beet using hybridisation techniques that detect restriction fragment length polymorphism. Probes have been identified which differ in the levels of variation that they can detect (i) within closely related genetic material of sugar beet, and (ii) between sugar beet and a taxonomically distant Beta species.
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    Springer
    Theoretical and applied genetics 84 (1992), S. 113-117 
    ISSN: 1432-2242
    Keywords: Beet ; Somaclonal variation ; Isozyme ; RFLP ; Genetic stability
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Sugar, fodder and garden beet (Beta vulgaris L.) plants have been regenerated in culture from a range of expiant material. Of the regenerants 764 were subjected to isozyme analysis using eight enzyme-specific stains, and 60 were subjected to RFLP analysis using three cDNA probes. Both molecular techniques allowed the identification of somaclonal variant plants. Assessment of the numbers of variant isozymes and restriction fragments has allowed the calculation of the approximate percentage of variant alleles occurring in any one somaclonal regenerant, namely between 0.05% and 0.1%.
    Type of Medium: Electronic Resource
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  • 5
    Electronic Resource
    Electronic Resource
    Springer
    Theoretical and applied genetics 90 (1995), S. 1049-1055 
    ISSN: 1432-2242
    Keywords: Oryza sativa ; Rice ; Genetic resources ; RAPD ; Molecular markers ; Cluster analysis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract A set of accessions of Oryza sativa from the International Rice Research Institute (Philippines) that included known and suspected duplicates as well as closely related germplasm has been subjected to RAPD analysis. The number of primers, the number of polymorphic bands and the total number of bands were determined that will allow the accurate discrimination of these categories of accessions, including the identification of true and suspected duplicates. Two procedures have been described that could be employed on a more general basis for identifying duplicates in genetic resources collections, and further discussion on the values of such activities is presented.
    Type of Medium: Electronic Resource
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  • 6
    ISSN: 1573-6849
    Keywords: Allium ; chiasmata ; crossing over ; genomic in situ hybridization ; recombination
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Genomic in situ hybridization (GISH) successfully differentiated homoeologous genomes in the interspecific hybrid Allium cepa × fistulosum, thus allowing the detection of reciprocal crossover events as label exchanges in separating anaphase I chromosomes. Three of the eight chromosome pairs were positively identified by fluorescence in situ hybridization (FISH) to rDNA sequences. There was a general similarity of the GISH-based label exchange frequencies and metaphase I chiasma frequencies, but with a 20% deficit of chiasmata. Reasons for this apparent deficit are discussed. The locations of chiasmata and label exchanges are in broad agreement.
    Type of Medium: Electronic Resource
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  • 7
    Electronic Resource
    Electronic Resource
    Springer
    Plant systematics and evolution 217 (1999), S. 31-42 
    ISSN: 1615-6110
    Keywords: Alliaceae ; Allium ; Fluorescent in-situ hybridisation ; cytotaxonomy ; telomeric repeat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Information about evolutionary relationships between species of the genusAllium is desirable in order to facilitate breeding programmes. One approach is to study the distribution of repetitive DNA sequences among species thought on taxonomic grounds, to be closely related. We have used fluorescent in-situ hybridisation (FISH) to examine seven species within sect.Cepa of the genus (A. altaicum, A. cepa, A. fistulosum, A. galanthum, A. pskemense, A. oschaninii andA. vavilovii), one species from sect.Rhizirideum (A. roylei), two species from sect.Allium (A. sativum andA. porrum) and one species from sect.Schoenoprasum (A. schoenoprasum). Each species was probed using a 375 bp repeat sequence isolated fromA. cepa (Barnes & al. 1985), which was generated and labelled by polymerase chain reaction (PCR). No signals were detected in anyAllium species not belonging to sect.Cepa with the exception ofA. roylei, whose designation in sect.Rhizirideum is now questioned. Within sect.Cepa the probe was found to hybridize to the ‘terminal’ regions of the chromosome arms of all the species examined. In addition a number of interstitial bands were detected. Use of FISH reveals a more detailed map of the location of the repeat sequences than has previously been obtained by C-banding and other staining procedures. The distribution of the terminal and interstitial sites when compared, allow us to identify three species groups namely,A. altaicum andA. fistulosum; A. cepa, A. roylei, A. oschaninii andA. vavilovii; andA. galanthum andA. pskemense.
    Type of Medium: Electronic Resource
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