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  • 1
    Electronic Resource
    Electronic Resource
    Springer
    Theoretical and applied genetics 68 (1984), S. 547-554 
    ISSN: 1432-2242
    Keywords: Wheat X rye hybrids ; Translocations ; Introgression ; Tissue culture ; C-banding
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The spontaneous occurrence of chromosome breaks, deletions, and translocations in plant tissue cultures is well documented. This study investigated the usefulness of tissue culture as a method of introgressing alien genes into wheat. Wheat X rye hybrids were regenerated from embryo scutellar calli maintained in culture for 222 days. The regenerated seedlings then were treated with colchicine to produce amphidiploids (AABBDDRR). The karyotypes of ten amphidiploids were analyzed by C-banding to determine chromosome structural changes that occurred during tissue culture. Three wheat/rye and one wheat/wheat chromosome translocations, seven deletions, and five amplifications of heterochromatin bands of rye chromosomes were identified. One amphidiploid contained a reciprocal translocation between wheat chromosome 4D and rye chromosome 1R. Non-reciprocal translocations between 2B and 3R, and between an unidentified wheat chromosome and 2R, were found independently in two amphidiploids. An additional plant had a translocation between wheat chromosomes 6B and 5A. All deletions involving rye chromosomes were noted in all 10 amphidiploids. Twelve of the 13 breakpoints in chromosomes involved in translocations and deletions occurred in heterochromatin. Amplification of heterochromatin bands on 2RL and 7RL chromosome arms also was observed in five plants. These results indicate a high degree of chromosome structural change induced by tissue culture. Therefore, tissue culture may be a useful tool in alien gene introgression and manipulation of heterochromatin in triticale improvement.
    Type of Medium: Electronic Resource
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  • 2
    ISSN: 1432-203X
    Keywords: Key words Anther culture ; DNA content ; Embryogenesis ; Flow cytometry ; Haploid
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Over 250 dihaploid lines derived from a disomic tetraploid genotype of Solanum acaule ssp. acaule Bitt. (acc. PI 472655) were produced via androgenesis. The anther donor plant had previously shown immunity to bacterial ring rot caused by Clavibacter michiganensis ssp. sepedonicus (Spieck. and Kotth.) Davis et al., and has now been shown to have high embryogenic capacity in anther culture. In total, 370 shoots were regenerated from 4,011 anthers cultured. The ploidy level of the 287 regenerants was determined from greenhouse-grown plants using flow cytometry. Of these plants, 274 (95%) were dihaploids with an average DNA content of 1.68 pg, approximately half that of the tetraploid anther donor (2.95 pg). The remainder of the anther-derived regenerants (5%) were tetraploid, hexaploid or mixoploid. Chromosome counts confirmed the results obtained by flow cytometry. In the greenhouse, none of the 33 dihaploid lines analysed produced berries but showed low (2%) male fertility. This contrasted with five greenhouse-grown tetraploid anther-derived plants which produced berries and seeds. Comparison of the general leaf morphology and floral characteristics of the tetraploid anther donor, S. acaule, and the dihaploids indicated that little variation exists in this species.
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    Springer
    Theoretical and applied genetics 75 (1988), S. 381-388 
    ISSN: 1432-2242
    Keywords: Amplification ; Repeated DNA sequences ; WheatX rye hybrids ; Tissue culture
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Previous C-banding analysis of wheat (Triticum aestivum)X rye (Secale cereale) hybrids regenerated from tissue culture revealed enlarged C-bands in some rye chromosomes, but the molecular nature of the change was not determined. In situ hybridization using two DNA probes containing repeated sequences from rye telomeric heterochromatin was conducted on these wheatX rye hybrids and their progeny to investigate the occurrence of amplification in repeated sequences. Clones pSC 74 and pSC 119, which contain sequences from the 480-bp and 120-bp repeated DNA families of rye, respectively, were used as probes. Amplification of 480-bp repeated sequences in the short arm telomere of chromosome 7R was detected in three wheatxrye hybrids and their progeny. The amplified 480-bp sequences were detected by an enlarged hybridization site for pSC 74 at the 7RS telomere, and by the appearance at this same telomeric site of an unlabeled, blue chromosome segment in an otherwise completely brown chromosome hybridizing entirely to the biotin-labeled pSC 119 probe. This variant form of chromosome 7R was not observed in several ‘Chaupon’ plants, or in the other hybrids derived from the same embryos, indicating the origin of the change in tissue culture. The amplified sequences were inherited up to at least three generations. Deletions and translocations were also observed.
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    Springer
    Theoretical and applied genetics 89 (1994), S. 865-872 
    ISSN: 1432-2242
    Keywords: Comparative mapping ; RFLP ; Barley ; Triticum tauschii ; Genome evolution
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Hordeum vulgare (barley) and Triticum tauschii are related, but sexually incompatible, species. This study was conducted to determine the extent of homology between the genomes of barley and T. tauschii using a common set of restriction fragment length polymorphism (RFLP) markers. Results showed that 〉95% of low-copy sequences are shared, but 42% of the conserved sequences showed copy-number differences. Sixty-three loci were mapped in T. tauschii using RFLP markers previously mapped in barley. A comparison of RFLP marker order showed that, in general, barley and T. tauschii have conserved linkage groups, with markers in the same linear orders. However, six of the seven linkage groups of T. tauschii contained markers which mapped to unrelated (i.e., non-homoeologous) barley chromosomes. Additionally, four of the T. tauschii linkage groups contained markers that were switched in order with respect to barley. All the chromosome segments differing between T. tauschii and barley contained markers that were detected by multi-copy probes. The results suggest that the observed differences between the T. tauschii and barley genomes were brought about by duplications or deletions of segments in one or both species. The implications of these findings for genetic mapping, breeding, and plant genome evolution are discussed.
    Type of Medium: Electronic Resource
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  • 5
    Electronic Resource
    Electronic Resource
    Springer
    Theoretical and applied genetics 91 (1995), S. 681-690 
    ISSN: 1432-2242
    Keywords: RFLP ; Barley ; Hordeum vulgare ssp. spontaneum ; Gramineae ; Comparative mapping
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Several gene linkage maps have been produced for cultivated barley. We have produced a new linkage map for barley, based on a cross between Hordeum vulgare subsp. spontaneum and Hordeum vulgare subsp. vulgare (Hvs x Hvv), having a higher level of polymorphism than most of the previous barley crosses used for RFLP mapping. Of 133 markers mapped in the Hvs x Hvv F2 population, 69 were previously mapped on other barley maps, and 26 were mapped in rice, maize, or wheat. Two known gene clones were mapped as well as two morphological markers. The distributions of previously mapped markers were compared with their respective barley maps to align the different maps into one consensus map. The distributions of common markers among barley, wheat, rice and maize were also compared, indicating colinear linkage groups among these species.
    Type of Medium: Electronic Resource
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  • 6
    ISSN: 1432-2242
    Keywords: Key words Aegilops tauschii ; Triticum aestivum ; Genetic mapping ; Molecular markers ; Agronomically important genes
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract  Aegilops tauschii is the diploid D-genome progenitor of bread wheat (Triticum aestivum L. em Thell, 2n=6x=42, AABBDD). A genetic linkage map of the Ae. tauschii genome was constructed, composed of 546 loci. One hundred and thirty two loci (24%) gave distorted segregation ratios. Sixty nine probes (13%) detected multiple copies in the genome. One hundred and twenty three of the 157 markers shared between the Ae. tauschii genetic and T. aestivum physical maps were colinear. The discrepancy in the order of five markers on the Ae. tauschii 3DS genetic map versus the T. aestivum 3D physical map indicated a possible inversion. Further work is needed to verify the discrepancies in the order of markers on the 4D, 5D and 7D Ae. tauschii genetic maps versus the physical and genetic maps of T. aestivum. Using common markers, 164 agronomically important genes were assigned to specific regions on Ae. tauschii linkage, and T. aestivum physical, maps. This information may be useful for map-based cloning and marker-assisted plant breeding.
    Type of Medium: Electronic Resource
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