Navegando por Autor "VEASEY, Elizabeth Ann"

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Assessing the genetic structure of Oryza glumaepatula populations with isozyme markers
(2008-10) VEASEY, Elizabeth Ann; CARDIM, Daruska Cavalcante; SILVA, Rainério Meireles da; BRESSAN, Eduardo de Andrade; VENCOVSKY, Roland
To assess the genetic diversity and genetic structure parameters, nine populations of Oryza glumaepatula from the Amazon biome, four from the Pantanal biome, and one collected at Rio Xingu, Mato Grosso, totaling 14 populations and 333 individuals were studied with isozyme markers. Six loci were evaluated showing a moderate allozyme variability (A = 1.21, P = 20.7%, Ho = 0.005, He = 0.060). The populations from the Pantanal biome showed higher diversity levels than the Amazon biome. High genetic differentiation among the populations, expected for self-fertilizing species, was observed (FST=0.763), with lower differentiation found among the Pantanal populations (FST=0.501). The average apparent outcrossing rate was higher for the Pantanal populations (ta = 0.092) than for the Amazonian populations (ta = 0.003), while the average for the 14 populations was 0.047, in accordance with a self-fertilization mating system.
Acesso aberto (Open Access)
Genetic diversity of American wild rice species
(Universidade Federal do Pará, 2011-08) VEASEY, Elizabeth Ann; BRESSAN, Eduardo de Andrade; ZUCCHI, Maria Imaculada; VENCOVSKY, Roland; CARDIM, Daruska Cavalcante; SILVA, Rainério Meireles da
Studies on genetic diversity and genetic structure of natural populations are important in order to define strategies for in situ and ex situ conservation actions and for plant pre-breeding programs. Aiming to assess the genetic diversity and genetic structure of three wild American Oryza species with isozyme markers, 14 populations of the diploid O. glumaepatula (AglAgl), 11 populations of the tetraploid O. grandiglumis (CCDD) and five populations of the also tetraploid O. latifolia (CCDD) were studied. They were all originated from Rio Paraguay hydrographic basin and the Amazon. Four enzymes were used and they gave 40 polymorphic bands. The most polymorphic species was O. glumaepatula, followed by O. latifolia and O. grandiglumis. A cluster analysis with the Jaccard similarity coefficient separated the diploid from the two tetraploid species, and also the two tetraploid species. This separation was also evident on a scatter plot from a principal component analysis, suggesting that they should be treated as two separate species, although further studies are necessary to provide support for this affirmative. The AMOVA analyses showed a high intrapopulational variability for O. latifolia (67.6%) and O. grandiglumis (52.2%), when compared to their interpopulational variability (32.4% and 47.8%, respectively), which suggests the hypothesis of a higher degree of outcrossing events within these species. When studying the correlation between the Jaccard dissimilarity coefficient and geographic distances, a spatial genetic structure was observed for O. glumaepatula only. These results are important for defining strategies of both in situ and ex situ conservation.