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  • Trifolium hirtum  (2)
  • Analytical Chemistry and Spectroscopy  (1)
  • 1
    ISSN: 1432-1939
    Keywords: Colonizing species ; Ecological genetics ; Gynodioccy ; Sex ratio ; Trifolium hirtum
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Male sterility has been recently discovered in Californian populations of rose clover (Trifolium hirtum). This study describes the frequency distribution of male sterility in Turkish and Californian populations, and compares fitness components of hermaphrodites and females. As male-steriles were found in Turkey, it is likely that they were introduced to California during the 1940's with the original material derived from Turkey. The spread of male-sterile genotypes in California has given rise to an asymmetrical frequency distribution of male sterility with positive skewness. The frequency of females has not exceeded fifty percent and it appears to be temporally stable in most of the Californian populations. The hypothesis that female frequencies and fitness differences between phenotypes are correlated was tested by comparing sex phenotypes in seven populations with contrasting levels of male sterility. The analysis of those populations showed no evidence for such a correlation as no significant differences were found between sex phenotypes for fecundity and seed germination. The hypothesis that females are maintained due to fitness differences in the progeny of hermaphrodites and females was experimentally tested in the population with maximum frequency of male-steriles. The results showed no significant differences in the demographic performance of the progenies of hermaphrodites and females. The present results are discussed in terms of the possible mechanism of maintenance of gynodioecy in rose clover.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Springer
    Genetica 85 (1992), S. 153-161 
    ISSN: 1573-6857
    Keywords: Gynodioecy ; inheritance of male sterility ; nucleocytoplasmic differentiation ; Trifolium hirtum
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The inheritance of male sterility was studied using a set of intra and interpopulation crosses from Californian populations of rose clover (Trifolium hirtum All.). The F2 gave higher frequencies of male steriles in interpopulation crosses than in intrapopulation crosses. Several F2 families gave ratios that were compatible with models of two and three complementary genes. However, the frequency distribution of male sterility among F3 families rejected such models. Given that single and two gene models were rejected, we interpret the results using a cytoplasmic-nuclear model with more than two restorer loci which is at least consistent with the observed results.
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    X-Ray Spectrometry 8 (1979), S. 11-13 
    ISSN: 0049-8246
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Physics
    Notes: An X-ray fluorescence method for the measurement of film and coating thickness has been described for use in situations where standard foils of the same material are not available for comparison. The method is based on the measurement of combined mass absorption coefficient of the coating element at the excitation and at the fluorescent energies using thin samples of a compound in which the coating element is present and then calculating the coating thickness using the fluorescence equation. The paper describes the theoretical approach and presents the result of the measurement of certain film and coating thicknesses which support the theoretical considerations.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
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