Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
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Showing 1 to 13 of 13 for “"self-fertilization"”.
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Concerning the Degree of Self Fertilization in Corn (Zea mays indentata) That is Obtained Under Normal Field Conditions
"Like begets like”. This well-known phrase which aroused so much comment among students in genetics and animal breeding has almost unconsciously become an adage to a part of their philosophy. Whatever truth or lack of it is associated with these words we admire the keenness of observation of him …
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Impact of self-fertilization on fecundity, the timing of first reproduction, and population genetic structure: Is a mate worth the wait?
Organisms capable of self-fertilization typically exhibit two evolutionary syndromes uniting high inbreeding depression with low levels of selfing, or low inbreeding depression and high levels of selfing. This study tests for inbreeding depression in an apparent self-compatible, hermaphroditic …
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The evolution of self-compatibility and its genetic consequences in Leavenworthia alabamica (Brassicaceae)
The evolution of self-fertilization from the outcrossing condition is a common transition in flowering plants which strongly alters the genetic structure of populations. In general, it is thought that self-fertilization may evolve in response to its innate transmission advantage or pollen …
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Inbreeding Depression in the Partially Selfing Perennial, Ruellia Humilis
… outcrossing via hawkmoths and automatically self-fertilizing cleistogamous flowers which have ensured a long history of partial selfing. Previous studies have indicated a loss of hawkmoth pollination in isolated populations of Southwest Missouri resulting in significantly increased levels of …
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Using molecular genetic techniques to detect outcrossing in natural populations of a self-fertilizing fish
… only vertebrate known to reproduce by internal self-fertilization; this process results in populations of homozygous clones. Most natural populations consist entirely of hermaphrodites, but phenotypically distinct, fertile males occur at frequencies up to 24% on some islands off the coast of …
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Evolution of floral and mating system variation in Camissoniopsis cheiranthifolia (Onagraceae): An evaluation of patterns and processes
… in the relative importance of outcrossing vs. self-fertilization. I combined geographic surveys of floral variation with genetic estimates of the proportion of seeds outcrossed (t) and confirmed that t covaried with corolla width and herkogamy in a predictable way both within and among …
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The molecular ecology of Vaccinium macrocarpon Aiton, the American cranberry
… and reproduces sexually predominantly by self-fertilization on upright stems. The objective of this project was to investigate genetic and clonal variation and phenotypic plasticity of V. macrocarpon. Specifically, I wanted to test whether there exists an inverse relationship between …
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Low Temperature Induction of Males and Other Developmental Anomalies in a Self-Fertilizing Hermaphroditic Fish Species
… known to reproduce by obligate internal self-fertilization. Selfing is the ultimate form of inbreeding and leads to virtual homozygosity in approximately ten generations, so that this mode of reproduction is effectively clonal. Populations of this species consist of arrays of homozygous …
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CMV Infection Affects Bumblebee Pollination Behaviour and Plant Reproductive Success
… the flowers, which releases pollen and enhances self-fertilization and seed production as well as pollen export. First, I established that CMV-infected tomato plants produced fruits with a lower seed yield than mock-inoculated plants. When single bumblebees were allowed to buzz-pollinate flowers …
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Variation at Major Histocompatibility Complex Class I Loci In Two Killifish Species with Reduced Genetic Variance
The ability of natural selection to promote and preserve genetic variation at Major Histocompatibility Complex (MHC) class I loci was examined in two fish species known to have low genetic variation either as a consequence of their breeding system or population structure. The tempo and modes of …
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Variation in breeding systems and consequences for reproductive traits in Erica
… floral traits with a shift from outcrossing to selfing. The aim of this thesis was to determine whether similar changes occur in Erica. I thus analysed breeding systems in Erica in relation to floral traits, pollinators, and fire survivals strategies. Seed and fruit set data obtained from …
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Studio molecolare dei meccanismi dell'autoincompatibilità gametofitica in pero europeo (Pyrus communis)
Self-incompatibility (SI) systems have evolved in many flowering plants to prevent self-fertilization and thus promote outbreeding. Pear and apple, as many of the species belonging to the Rosaceae, exhibit RNase-mediated gametophytic self-incompatibility, a widespread system carried also by the …
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Evolutionary dynamics of mating systems in populations of North American Arabidopsis lyrata
… outcrossing perennial due to a sporophytic self incompatibility (SI) system. The species occurs in temperate regions of the Northern hemisphere where in Europe its SI system is fully working but around the Great Lakes of North America some populations of A. lyrata show a breakdown in SI. …