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  • 1
    Electronic Resource
    Electronic Resource
    Springer
    Genetica 45 (1975), S. 177-190 
    ISSN: 1573-6857
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Recent developments in the study of aneuploids in barley are reviewed. To date five complete series of primary trisomics have been produced. Considerable progress has been made toward the production of a complete set of monotelotrisomics. Eleven of the possible 14 have thus far been identified though not all in the same genetic background. Studies on existing monotelotrisomics have shown that those representing the long arm frequently resemble the corresponding primary trisomic in gross morphology while short arm counterparts are rarely distinguishable from diploids. The average transmission rate of extra telos through female gametes was 31.9% with all showing a low rate of male transmission. In 81.3% of cells at metaphase 1 of meiosis the extra telos are synapsed with normal homologues to form heteromorphic trivalents. Tandem-chain configurations were the predominant type.
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  • 2
    ISSN: 1432-2242
    Keywords: Intergeneric hybrids ; Embryo culture ; Homoeologous chromosome pairing ; Triticum ; Hordeum
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Intergeneric hybrids between Triticum crassum (2n=6x=42) and Hordeum vulgare cv. ‘Bomi’ were obtained at a frequency of 15% of pollinated florets. Meiotic chromosome pairing in the hybrids was not different from that observed in a polyhaploid of T. crassum indicating negligible pairing between chromosomes of the two species and secondly that the genome of H. vulgare had no effect on intergenomic pairing in T. crassum.
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  • 3
    ISSN: 1432-2242
    Keywords: Triticum ; x Triticosecale ; Secale ; Rye ; Meiosis ; Chromosome pairing ; Heterochromatin
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Meiotic pairing in Triticum turgidum cv. Ma (4x) with a mean chiasmata frequency of 27.16 per cell was compared with chiasmata frequencies in its hybrids with several triticale strains, ‘Chinese Spring’ wheat and its addition lines for ‘Imperial’ rye chromosomes 4R and 6R. In hybrids between ‘Ma’ and x Triticosecale cv. ‘Rosner’ the chiasmata frequency was marginally reduced by an average of 1.25%, by 8.8% in hybrids with x Triticosecale cv. ‘DRIRA’ HH and by 6.7% with ‘DRIRA’ EE (lacking 90% telomeric heterochromatin from chromosome arm 7RL). In pentaploid hybrids between ‘Ma’ and T. aestivum cv. ‘Chinese Spring’ the reduction was an average of 10.30%, while addition lines with rye chromosome 6R reduced chiasmata frequencies by an average of 7.4% and rye addition line for 4R showed the greatest depression in chiasmata frequency in hybrids by a 25.04% reduction. An interchange difference involving long chromosome segments was observed between ‘Ma’ and ‘Rosner’.
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  • 4
    ISSN: 1432-2242
    Keywords: Russian wild rye ; Wheat ; Chromosome pairing ; Meiosis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Two hybrid embryos of intergeneric origin between Triticum aestivum cv Fukuho (2n=6x=42, AABBDD) and Psathyrostachys juncea (2n=2x=14, NN) were successfully rescued. One hybrid plant had the expected chromosome number of 28 (ABDN), whereas the second plant had 35 chromosomes. The average meiotic chromosome pairing in the 35-chromosome hybrid was 21.87 univalents + 6.38 bivalents + 0.11 trivalents + 0.009 quadrivalents, which indicates that two copies of the N genome were present. Chromosome pairing in the 28-chromosome hybrid was low (1.35 bivalents), and pointed out the lack of homology between the wheat genomes and the P. juncea genome. These new hybrids showed some necrosis and chlorosis, which caused severe floral abortion in the plant that had 35 chromosomes. These problems became gradually less severe after 18 months.
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  • 5
    ISSN: 1432-2242
    Keywords: Hordeum ; Barley ; Ribosomal DNA ; Polymorphism ; Restriction analysis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Tandemly repeated DNA sequences containing structural genes encoding ribosomal RNA (rDNA) were investigated in 25 species of Hordeum using the wheat rDNA probe pTA71. The rDNA repeat unit lengths were shown to vary between 8.5 and 10.7 kb. The number of length classes (1–3) per accession generally corresponded to the number of nucleolar organizing regions (NORs). Intraspecific variation was found in H. parodii, H. spontaneum and H. leporinum, but not in H. bulbosum. Restriction analysis showed that the positions of EcoRI, SacI and certain BamHI cleavage sites in the rRNA structural genes were highly conserved, and that repeat unit length variation was generally attributable to the intergenic spacer region. Five rDNA BamHI restriction site maps corresponded to the following groups of species: Map A — H. murinum, H. glaucum, H. leporinum, H. bulbosum, H. marinum, H. geniculatum; Map B — H. leporinum; Map C — H. vulgare, H. spontaneum, H. agriocrithon; Map D — H. chilense, H. bogdanii; and Map E — remaining 14 Hordeum species. The repeat unit of H. bulbosum differed from all other species by the presence of a HindIII site. The closer relationship of H. bulbosum to H. leporinum, H. murinum and H. glaucum than to H. vulgare was indicated by their BamHI restriction maps.
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  • 6
    ISSN: 1432-2242
    Keywords: Thinopyrum ponticum ; Th. intermedium ; Th. junceum ; Wheat ; BYDV ; Genome
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Twenty-five partial amphiploids (2n=8x=56), which were derived from hybrids of wheat (Triticum aestivum L.) with either Thinopyrum ponticum (Podpera) Liu & Wang, Th. intermedium (Host) Barkworth & D. Dewey, or Th. junceum (L.) A. Löve, were assayed for resistance to BYDV serotype PAV by slot-blot hybridization with viral cDNA of a partial coat protein gene. Three immune lines were found among seven partial amphiploids involving Th. ponticum. Seven highly resistant lines were found in ten partial amphiploids involving Th. intermedium. None of eight partial amphiploids or 13 addition lines of Chinese Spring — Th. junceum were resistant to BYDV. Genomic in situ hybridization demonstrated that all of the resistant partial amphiploids, except TAF46, carried an alien genome most closely related to St, whether it was derived from Th. ponticum or Th. intermedium. The two partial amphiploids carrying an intact E genome of Th. ponticum are very susceptible to BYDV-PAV. In TAF46, which contains three pairs of St- and four pairs of E-genome chromo somes, the gene for BYDV resistance has been located to a modified 7 St chromosome in the addition line L1. This indicates that BYDV resistance in perennial polyploid parents, i.e., Th. ponticum and Th. intermedium, of these partial amphiploids is probably controlled by a gene(s) located on the St-genome chromosome(s).
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  • 7
    ISSN: 1432-2242
    Keywords: Key wordsThinopyrum ponticum ; Th. intermedium ; Th. junceum ; Wheat ; BYDV ; Genome
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Twenty-five partial amphiploids (2n=8x=56), which were derived from hybrids of wheat (Triticum aestivum L.) with either Thinopyrum ponticum (Podpera) Liu & Wang, Th. intermedium (Host) Barkworth & D. Dewey, or Th. junceum (L.) A. Löve, were assayed for resistance to BYDV serotype PAV by slot-blot hybridization with viral cDNA of a partial coat protein gene. Three immune lines were found among seven partial amphiploids involving Th. ponticum. Seven highly resistant lines were found in ten partial amphiploids involving Th. intermedium. None of eight partial amphiploids or 13 addition lines of Chinese Spring –Th. junceum were resistant to BYDV. Genomic in situ hybridization demonstrated that all of the resistant partial amphiploids, except TAF46, carried an alien genome most closely related to St, whether it was derived from Th. ponticum or Th. intermedium. The two partial amphiploids carrying an intact E genome of Th. ponticum are very susceptible to BYDV-PAV. In TAF46, which contains three pairs of St- and four pairs of E-genome chromosomes, the gene for BYDV resistance has been located to a modified 7St chromosome in the addition line L1. This indicates that BYDV resistance in perennial polyploid parents, i.e., Th. ponticum and Th. intermedium, of these partial amphiploids is probably controlled by a gene(s) located on the St-genome chromosome(s).
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  • 8
    ISSN: 1432-2242
    Keywords: Intergeneric hybrids ; Giemsa banding ; Homoeologous chromosome pairing
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Chromosome pairing was studied in hybrids of (Hordeum vulgare ×Triticum aestivum) ×Secale cereale. Chiasma frequency per cell varied from 1.94 to 3.16 between the different hybrids. This variation was attributed to genetic variability in rye parents which affected homoeologous pairing. The pairing of rye chromosomes as revealed by Giemsa C-banding was a combination of nonhomologous association between rye chromosomes and associations with chromosomes of wheat and barley.
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  • 9
    ISSN: 1432-2242
    Keywords: Hordeum ; Agropyron ; X Triticosecale ; Interspecific and intergeneric hybrids ; Chromosome pairing
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Hybrids were produced from crossing Hordeum vulgare, H. bogdanii, Agropyron caninum and × Triticosecale onto H. parodii (6x or 4x). The rates at which hybrids were produced, expressed in terms of plantlet establishment as percent pollinated florets, ranged from 0.47%, (6x H.parodii × 6x × Triticosecale cv. ‘Welsh’) to 6.3% (4x H. parodii × 2x H. vulgare cv. Betzes). Based on frequencies of paired configurations at MI, autosyndetic pairing appeared to be promoted by the presence of a Secale cereale genome but suppressed by the genome of H. vulgare.
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  • 10
    ISSN: 1432-2242
    Keywords: Intergeneric hybrids ; Wheat ; Leymus ; Chromosome pairing ; Meiosis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Hybrid plants were obtained between Triticum aestivum (2n=6x=42, AABBDD) and Leymus innovatus (2n=4x=28, JJNN) at a frequency varying from 0.4% to 1.2% of the pollinated florets. Improvement of the embryo culture medium resulted in a higher frequency of embryo rescue. Eight of ten hybrids had the expected chromosome number of 35 (ABDJN). Meiotic analysis indicated that there was no homology between the genomes of the two species. Two hybrids had only 28 chromosomes. Comparison of chromosome pairing between the two types of hybrids suggested that Leymus innovatus carries genes that affect chromosome pairing and behavior. The relatively high occurrence of spontaneous doubling in the meiocytes of these hybrids may indicate that backcrossing of the hybrids to wheat should be possible, although frequent chromosome irregularities observed in the meiocytes of the hybrids may decrease the probability of success of this step, which is essential to the process of gene transfer from L. innovatus to wheat.
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