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  • 11
    Digitale Medien
    Digitale Medien
    Springer
    Theoretical and applied genetics 57 (1980), S. 43-47 
    ISSN: 1432-2242
    Schlagwort(e): Oryza sativa ; Heading date ; Diallel ; Complementary interaction ; Overdominance
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary The genetics of heading date was investigated in an 8×8 diallel set of crosses involving diverse rice cultivars. Wr, Vr graph analysis revealed the presence of a complementary type of non-allelic interaction which apparently affected the position and slope of the regression line such as if there were overdominance. Omission of two interacting parents resulted in a 6×6 subset of diallel crosses from which, as observed in the Wr, Vr graph, the non-allelic interaction had disappeared and the regression line exhibited partial dominance. Estimates of the genetic components of variation were in close conformity with the results obtained from the Wr, Vr graph: the average degree of dominance, as measured by (H1/D)1/2, was in overdominance range in the interacting 8×8 set of diallel crosses whereas it was reduced to partial dominance in the non-interacting 6×6 set of crosses. Further analysis by a standardized deviations graph indicated that earliness was controlled, on the average, by an excess of dominant alleles.
    Materialart: Digitale Medien
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  • 12
    Digitale Medien
    Digitale Medien
    Springer
    Astrophysics and space science 180 (1991), S. 133-142 
    ISSN: 1572-946X
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Physik
    Notizen: Abstract The integral balance method has been used to obtain an approximate analytical solution of a nonlinear boundary value problem which arises in the theory of diffusion with a concentration-dependent coefficient. It is the purpose of this paper to give an interpretation of the supposition of interface reactions which obey the law of kinetic mass action.
    Materialart: Digitale Medien
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  • 13
    Digitale Medien
    Digitale Medien
    Springer
    Genetica 56 (1981), S. 213-215 
    ISSN: 1573-6857
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Data on genetic polymorphism, scored at two morphological loci, showed peripheral, isolated roadside colonies of slender oat (Avena barbata) to be significantly less polymorphic than the large central populations in continuous stands. The role of random drift (founder effect) was evident in the genetic structure of such roadside colonies which were, however, not monomorphic. Multilocus associations also suggested large Hill-Robertson effect in generating gametic disequilibria. Such isolates with varying amounts of elapsed time since the founder events could offer useful material for a study of evolutionary processes including the selection-drift balance.
    Materialart: Digitale Medien
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  • 14
    Digitale Medien
    Digitale Medien
    Springer
    Euphytica 52 (1991), S. 25-31 
    ISSN: 1573-5060
    Schlagwort(e): Pennisetum glaucum ; pearl millet ; dwarfing gene ; near-isogenic lines ; yield and yield components
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Summary A d2 dwarfing gene in pearl millet [Pennisetum glaucum (L.) R. Br.] is currently being extensively used for the development of hybrid parents. Its effect on grain yield and yield components is poorly understood. Twelve pairs of tall and dwarf near-isogenic lines developed in the diverse genetic background of three composites were evaluated for grain yield and yield components for 2 years at two locations in southern India. The d2 gene or the genes linked to it, on an average, reduced plant height by 42%, grain yield by 14%, and head girth by 8% but increased head length and number of tillers per plant by about 5–6%. Large variations were observed among pairs (genetic background) for the difference between tall and dwarf near-isogenic lines for all of the above yield components resulting in no significant difference in five pairs and 17–35% less yield in dwarfs as compared to their tall counterparts in six pairs. Days to 50% flowering and seed weight were least affected by the d2 gene with the average difference between tall and dwarf groups of near-isogenic lines being of the order of 1–2%. These results indicate that the advantageous effects of d2 dwarfing gene can be effectively exploited by manipulating the genetic background. The difference between the average grain yields of tall and dwarf groups of near-isogenic lines showed considerable variation across environments with the dwarfs yielding as much as tall group in one environment and up to 30% less than the tall group in the other, thus, indicating that the d2 gene effect may be substantially modified by the environments.
    Materialart: Digitale Medien
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  • 15
    Digitale Medien
    Digitale Medien
    Springer
    Euphytica 90 (1996), S. 31-37 
    ISSN: 1573-5060
    Schlagwort(e): pearl millet ; Pennisetum glaucum ; smut ; Tolyposporium penicillariae ; cytoplasmic-nuclear male sterility
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Summary Pearl millet (Pennisetum glaucum (L.) R. Br.) hybrids based on the A1 cytoplasmic-nuclear male-sterile (CMS) lines are more susceptible to smut (Tolyposporium penicillariae Bref.) than open-pollinated varieties. Seventy eight pairs of hybrids, made onto male-sterile (A) lines and their counterpart maintainer (B) lines, were evaluated to examine the effects of male sterility and genetic resistance of parental lines on the smut severity of hybrids. The A-line hybrids had higher smut severity and lower selfed seedset than the counterpart B-line hybrids, indicating that it is the CMS-mediated male sterility rather than the A1 cytoplasm per se that caused greater smut severity of A-line hybrids. However, with the use of resistant parental lines even male-sterile hybrids of A-lines, in several cases, were as resistant as some of the highly resistant male-fertile hybrids of B-lines. It would be possible to produce smut resistant hybrids (〈 10% severity) on A-lines, albeit in low frequency, even if only one parent of a hybrid were resistant. However, the probability of producing such hybrids would be higher when both parents were resistant to smut. Thus, improvement in smut resistance of parental lines and fertility restoration ability of pollinators would provide the most effective genetic approach to smut disease management in hybrids.
    Materialart: Digitale Medien
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  • 16
    Digitale Medien
    Digitale Medien
    Springer
    Euphytica 83 (1995), S. 225-231 
    ISSN: 1573-5060
    Schlagwort(e): Pennisetum glaucum ; Claviceps fusiformis ; cytoplasmic-nuclear male sterility ; genetic resistance ; pearl millet ; ergot
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Summary High ergot (Claviceps fusiformis Loveless) susceptibility of pearl millet (Pennisetum glaucum (L.) R. Br.) hybrids has often been associated with the A1 cytoplasm of male-sterile lines (A-lines). To understand the underlying basis of this association and to examine the prospects of breeding ergot-resistant hybrids, we evaluated 56 hybrids and their 15 parental lines for ergot reaction and selfed seedset for 2 years in disease nurseries at ICRISAT Asia Center. Hybrids were made by crossing seven pollen parents (2 susceptible and 5 resistant) onto two resistant and two susceptible A-lines, and their four corresponding maintainer lines (B-lines). A-lines had no selfed seedset while B-lines had 32–75% selfed seedset. Hybrids of A-lines had significantly less selfed seedset than the hybrids of the corresponding B-lines. The reduced seedset of A-lines and their hybrids, however, was not always accompanied by significantly higher ergot susceptibility. Highly resistant hybrids were obtained where both A-lines and pollen parents were highly resistant, regardless of male fertility levels of the hybrids. Thus, although the A1 cytoplasm, by its reduction of male fertility, had a large and significant effect in increasing ergot severity of hybrids, the contribution of nuclear genetic factors of female parents was about 1.8 times larger than that of the cytoplasm.
    Materialart: Digitale Medien
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  • 17
    Digitale Medien
    Digitale Medien
    Springer
    Journal of materials science 31 (1996), S. 1481-1487 
    ISSN: 1573-4803
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Maschinenbau
    Notizen: Abstract ZrO2 and its modified versions containing MgO and Y2O3 were selected as particulate reinforcement in order to achieve better mechanical properties of mullite. Particulate composites up to 25 vol % ZrO2 and its modifications were pressed to 55% relative density at 300 MPa followed by sintering at 1600°C and 1650°C for one hour. Studies were conducted on fracture toughness, transverse rupture strength, hardness, dielectric constant, microstructure and fractography. Composites sintered at 1650°C were found superior in properties than those at 1600°C. The maximum strength of mullite composites was observed at a composition of 10 vol % ZrO2.
    Materialart: Digitale Medien
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  • 18
    ISSN: 1432-2242
    Schlagwort(e): Key words Cytoplasmic-nuclear male sterility ; Pearl millet ; Pennisetum glaucum ; RFLP
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract  The identification of diagnostic cytoplasmic molecular markers is of prime interest to pearl millet breeders wishing to identify sources of cytoplasmic-nuclear male sterility (CMS) which can be used as an alternative to the single source currently used in the production of F1 hybrid seed. Here, we report the classification of five pearl millet CMS sources based on RFLP analysis of isonuclear lines carried out using mitochondrial gene-specific DNA probes in combination with eight restriction endonucleases. On the basis of RFLP data, the five CMS cytoplasms can be distinguished from each other and from the isonuclear fertile cytoplasm. In addition, based on cox1, cox3, atp6 and atp9 polymorphisms, these lines can be classified into two major groups: one corresponds to A5, Aegp, Av and A1 cytoplasms, and the other consists of the A4 cytoplasm. Our results suggest that a rearrangement involving the cox1 gene might be related to CMS in the first group (A5, Aegp, Av and A1), whereas a rearrangement within the atp6/cox3 cluster region might be related to CMS in the second group (A4).
    Materialart: Digitale Medien
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  • 19
    Digitale Medien
    Digitale Medien
    Springer
    Journal of materials science 22 (1987), S. 1908-1912 
    ISSN: 1573-4803
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Maschinenbau
    Notizen: Abstract Microstructure, composition and magnetic property correlations have been attempted for directionally solidified dilute Bi-Mn alloys. The ingots exhibited predominantly acicular BiMn precipitate particles in a bismuth matrix, and showed magnetic anisotropy along the direction of solidification. The saturation magnetization has been found to increase linearly with the weight percentage of manganese over the entire composition range investigated, starting from the hypoeutectic (0.15% Mn) to the hypereutectic (6.6% Mn) region. The intrinsic coercivity has been observed to be a maximum along the direction of solidification, but it decreased with manganese content in both the as-cast and the directionally solidified alloys. The results are discussed in terms of the crystal anisotropy, shape anisotropy and packing factor of the magnetic particles.
    Materialart: Digitale Medien
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  • 20
    Digitale Medien
    Digitale Medien
    Hoboken, NJ : Wiley-Blackwell
    AIChE Journal 31 (1985), S. 1997-2007 
    ISSN: 0001-1541
    Schlagwort(e): Chemistry ; Chemical Engineering
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie , Werkstoffwissenschaften, Fertigungsverfahren, Fertigung
    Notizen: The inclusion of Re in Pt-Re-Al2O3 reforming catalysts to improve the lifetime is known, but how rhenium functions and how it is disposed in the catalyst remain unclear. These fundamental questions have been attempted in this study by the use of proton-induced X-ray emission and Rutherford backscattering spectrometry (together with electron microscopy and chemisorption studies) to characterize a commercial like catalyst for dehydrogenation of methylcyclohexane.
    Zusätzliches Material: 14 Ill.
    Materialart: Digitale Medien
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