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  • Electronic Resource  (7)
  • Physics  (4)
  • Vigna unguiculata  (3)
  • 1
    ISSN: 1573-5060
    Keywords: Striga gesnerioides ; Vigna unguiculata ; cowpea ; parasitic angiosperm ; breeding for resistance ; parasite variation ; races
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract An in vitro growth system was used to determine the virulence of two samples of Striga gesnerioides from Zakpota in southern Benin. Cowpea variety B301, previously considered resistant to all races of S. gesnerioides, was susceptible to both samples of the parasite. Two other cowpea varieties, 58–57 and IT81D-994, were totally resistant. Resistance in 58–57 was associated with a hypersensitive necrosis of infected roots, whilst IT81D-994 supported production of small S. gesnerioides tubercles with stems which failed to develop. Striga gesnerioides from southern Benin is the fourth race of the parasite to be identified, and the first with virulence on variety B301. The implications for breeding cowpeas with resistance to S. gesnerioides are discussed.
    Type of Medium: Electronic Resource
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  • 2
    ISSN: 1573-5060
    Keywords: Vigna unguiculata ; cowpea ; early generation selection ; single seed descent selection
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary Two breeding procedures were compared in two cowpea crosses. Both procedures were started from the same selected F2 plants in each cross. For the early generation yield testing, the F3 lines were yield tested and a pedigree and bulk methods followed in F4 and F5. Each F5 line was bulked to provide seed for a yield test in F6. In the Single Seed Descent (SSD) procedure, a single seed was taken from each F2 plant to produce the F3 generation. The procedure was repeated for the F4 and F5. The F6 SSD lines and the F6 yield testing lines were compared in yield tests. The results showed that differences in yielding ability of F3 lines persisted over generations indicating that selection was effective. This was confirmed by the high significant correlations between F3 yields and those of later generations which ranged from r=0.51* to 0.85**. The grain yields of lines derived by the single seed descent procedure were as good as those derived from early generation yield testing. Significant linear correlation between visual rating of F3 and F6 yields with actual yields revealed that it is possible to identify promising lines of cowpea visually.
    Type of Medium: Electronic Resource
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  • 3
    ISSN: 1573-5060
    Keywords: cowpea ; intercropping ; Nigeria ; yield stability ; Vigna unguiculata
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary Nine cowpea (Vigna unguiculata (L.) Walp.) breeding lines were grown in 13 experiments under sole crop and intercrop management, with and without insecticide application, in Nigeria. Cowpea was intercropped with cassava (Manihot esculenta Cranz), maize (Zea mays L.) and maize-cassava in the forest zone and with sorghum (Sorghum bicolor Moench.) and millet (Pennisetum glaucum (L.) R.Br.) in the savanna zone. Line by cropping system interactions were significant in 5 of 13 experiments and line by insecticide treatment interactions were significant in 2 of 13 experiments. Cowpea yield was severely depressed in intercropped plots and in plots to which no insecticide was applied. Among-environment variation in cowpea yield was greater when no insecticide was applied. Within each management treatment, the yield performance and stability of the cowpea lines was examined. Stability was assessed both by examining among-environment coefficients of variation and by regression analysis. Several of the breeding lines evaluated appeared promising under different levels of management and in a diversity of environments.
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    New York : Wiley-Blackwell
    Journal of Polymer Science: Polymer Chemistry Edition 13 (1975), S. 2075-2086 
    ISSN: 0360-6376
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Kinetics of vinyl polymerization of acrylonitrile initiated by the redox system tartaric acid-V5+ have been investigated in aqueous sulfuric acid in the temperature range 30-40°C. The rates of polymerization and V5+ disappearance and the chain lengths of polyacrylonitrile were measured. From the results it is concluded that the polymerization reaction is initiated by an organic free radical arising from the V5+-tartaric acid reaction with termination by V5+ ions. A suitable kinetic scheme has been proposed, and the various rate and energy parameters were evaluated.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
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  • 5
    Electronic Resource
    Electronic Resource
    New York : Wiley-Blackwell
    Journal of Polymer Science: Polymer Chemistry Edition 21 (1983), S. 1165-1171 
    ISSN: 0360-6376
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The Kelen-Tüdös linear graphical method was used to determine the copolymerization parameters of some halogen-substituted (e.g., Cl, Br, I) aniline monomers. It was found during copolymerization with p-aminobenzoic acid or p-aminophenol that the reactivity of these monomers followed the order of their basic strength. The order of their basic strength. The order of their reactivity, however, was reversed if they copolymerized with sulfanilic acid (SA). This reversal has been interpreted in terms of the resonance stabilization of monomers, the nature of the acidic functional groups present in the comonomer, and the influence of electron-accepting or electron-donating groups present in the comonomers.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
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  • 6
    Electronic Resource
    Electronic Resource
    New York : Wiley-Blackwell
    Journal of Polymer Science Part A-1: Polymer Chemistry 10 (1972), S. 2655-2660 
    ISSN: 0449-296X
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The nature and behavior of free radicals induced in acetylated cotton celluloses irradiated with γ-rays have been studied by electron spin resonance (ESR) spectroscopy. Dehydrogenation and deacetylation appear to be responsible for the free radicals observed from samples irradiated at 77°K. The degree of substitution enhanced the yield of acetyl radicals when the samples were irradiated at 77°K and adversely affected the overall radical concentration when irradiation was done at 300°K. In addition, the ESR spectra of samples irradiated under vacuum at 300°K were more intense than those obtained from samples irradiated in air. The nature, yield, and post-irradiation behavior of the primary radicals are discussed in the light of the ultimate chemical effects observed.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
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  • 7
    ISSN: 0449-296X
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: With a view to assessing the role of chemical substitutions in the modification of radiation effects on cotton fibers, the induction and post-irradiation behavior of free radicals in γ-irradiated pure, mercerized, benzoylated, and allylated cottons have been investigated by ESR spectroscopy. While mercerization and allylation were found to influence both the nature and yield of radicals, benzoylation reduced only the yield. These substitutions, which have been found to protect cotton fibers against radiation damage, therefore act differently at the molecular level.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
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