Variabilidade e divergência genética de caracteres quantitativos e marcadores neutros em populações de Eugenia dysenterica DC
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2014-10-16
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Universidade Federal de Goiás
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Genotypic variations knowledge is an important tool that can point to the best approach for genetic resources maintenance, for both conservation and breeding purposes. To analyze and compare the phenotypic and genetic variation of wild subpopulations of Eugenia dysenterica DC., a fruity tree, 25 subpopulations were sampled in five states of the Brazilian Cerrado. Within each subpopulation, six trees were sampled and twenty fruits (maternal siblings) collected. Five fruits of each family were evaluated for morphometric variables of fruits and seeds. Twenty seeds of each family were randomly sown in each one of four blocks, five seeds per plot, established in a common garden experiment. Hierarchical model analysis of variance and variance components estimation were performed for fruit, seeds and early development traits and QST were estimated for early development traits. Four individuals per family were genotyped using nine microsatellite loci. Significant phenotypic and genotypic variations were observed both between subpopulations and between families within subpopulations. The highest proportion of the variance was found among families. Heritability estimates were 0.23 and 0.27 for growth rate and number of leaves and greater than 0.34 for other traits, indicating high potential for selective gain. Rapid early development is important for seedlings commercial production. Above ground biomass represented 15% of total biomass. Subpopulations are significantly structured for root length, height and diameter growth rates (QST 0.34, 0.23 and 0.20), but weak structure was establish for biomass and seedling emergence (QST <0.04). It has high genetic diversity, with average expected heterozigosity of 0.642. The mating system was mainly outcrossing (ta = 0.73), with high genetic differentiation between subpopulations (θP = 0.198), similar to previous studies. QST - FST contrasts were not significant for sixteen out of eighteen traits, suggesting genetic drift as the main source of phenotypic differentiation. Even though seedling emergence average time and root system fresh mass genetic similarity is granted to uniform selection. Quantitative and genetic distances clustered two distinct groups spatially structured, with respect to the Corumbá and São Bartolomeu river valley, in addition to the Chapada dos Veadeiros and Vão do Paranã region. Subpopulation 21 (Cocalinho-MT) quantitatively diverged from the two clusters. An in vivo collection of E. dysenterica was established for ex situ conservation. Genetic characterization and sampling extent suggest that the collection portrays well the cagaiteira’s wild population for selection purposes.
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NOVAES, Carolina Ribeiro Diniz Boaventura. Variabilidade e divergência genética de caracteres quantitativos e marcadores neutros em populações de Eugenia dysenterica DC. 2014. 223 f. Tese (Doutorado em Genética e Melhoramento de Plantas) - Universidade Federal de Goiás, Goiânia, 2014.