No Brasil, a ferrugem, causada pelo fungo Puccinia psidii Winter, se destaca como a mais importante doença da cultura do eucalipto, principalmente na região Sudeste do país. O uso de genótipos resistentes é o principal método de controle da doença, o que torna essencial o conhecimento das bases genéticas da resistência para a seleção de genótipos resistentes. Neste estudo, uma progênie F1 de 90 irmãos completos foi utilizada para identificar marcadores ligados a genes de resistência a este patógeno. A severidade da doença foi avaliada em quatro épocas ao longo de uma epidemia por meio de escala diagramática e os dados foram utilizados para o cálculo da área sob a curva de progresso da doença (AUDPC) para cada indivíduo. O delineamento experimental foi de blocos incompletos em dois ambientes e os valores de AUDPC foram analisados por meio de modelos mistos, excluindo-se a variação ambiental. Um mapa genético foi construído com base em marcadores microssatélites, AFLP e TRAP através de uma análise multiponto. O mapeamento de QTL seguiu duas abordagens: mapeamento por intervalos (IM) e mapeamento por intervalos compostos (CIM). No mapa de ligação foram posicionados 117 marcadores microssatélites, 10 TRAP e 33 AFLP, distribuídos por 11 grupos de ligação, totalizando 1075 cM com distância média de 6,7 cM entre marcadores. A análise de IM identificou um QTL (LOD=7,7) no grupo de ligação 3, representando 28,5% da variação em AUDPC na progênie observada. Já a análise CIM detectou dois QTL, ambos no grupo de ligação 3. A posição do primeiro QTL coincidiu com aquela do QTL identificado na análise por IM, porém com maior valor de LOD (10,3), explicando 39,5% da variação em AUDPC. O segundo QTL (LOD=3,4), cujo valor probabilístico máximo distou 39,0 cM do primeiro QTL, explicou 6,9% da variação fenotípica. Os alelos de resistência nos dois QTL se encontram em repulsão, com efeito aditivo negativo (=-0,60) e ausência de dominância no primeiro QTL e efeito aditivo positivo (=0,29) e dominância completa (=-0,23) no segundo QTL. Os marcadores ligados aos dois QTLs têm potencial utilização na seleção assistida, com conseqüente aumento na eficiência durante a seleção de genótipos resistentes. / In Brazil, the eucalyptus rust, caused by Puccinia psidii Winter, stands out as the most important disease of eucalypts, mainly in southeastern Brazil. The use of resistant genotypes is the main control method, which makes the understanding of the genetic basis of resistance essential to the selection of resistant genotypes. In this study, an F1 progeny of 90 plants was used to identify markers linked to resistance genes to this pathogen. Four disease severity assessments were conducted during an epidemic with a diagrammatic scale and the data were used to calculate the area under the disease progress curve (AUDPC) for each plant. The experimental design consisted of incomplete blocks in two environments. AUDPC values were analyzed using mixed models, excluding the environmental variation between locations. A genetic map was constructed based on microsatellite, AFLP and TRAP markers based on a multipoint analysis. QTL mapping was done based on two approaches: interval mapping (IM) and composite interval mapping (CIM). The linkage map consisted of 117 microsatellite, 10 AFLP and 33 TRAP markers, placed over 11 linkage groups, totalizing 1075 cM with an average distance of 6.7 cM between markers. IM analysis identified a QTL (LOD = 7.7) on linkage group 3, accounting for 28.5% of the phenotypic variation in AUDPC. The CIM analysis detected two QTL, both on linkage group 3. The position of the first QTL coincided with that of the QTL identified in the IM analysis, but with a higher LOD (10.3), accounting for 39.5% of the variation. The second QTL (LOD = 3.4), whose maximum probability value was placed 39.0 cM away from the first QTL, accounted for 6.9% of the phenotypic variation. The resistance alleles in the two QTL are linked in repulsion with negative additive effect ( =- 0.60) and lack of dominance in the first QTL and positive additive effects (=0.29) and complete dominance (=-0.23) in the second. The markers linked to the two QTL have potential use in assisted selection, thus increasing the efficiency of selection of resistant genotypes.

O fenótipo de caracteres complexos é o produto final da inter-relação entre genes, vias ontogenéticas e efeitos ambientais. A variação desses fatores não apenas influencia o fenótipo final, mas também como caracteres covariam e evoluem de forma integrada. A seleção natural pode influenciar a integração entre caracteres, levando a mudança de padrões de correlação ao longo do tempo. Assim, uma visão integrativa e dinâmica de fenótipos complexos é essencial para a compreensão da história evolutiva destas estruturas. Na tese atual investiguei a integração morfológica de caracteres cranianos em Caniformes sob duas perspectivas. Em uma primeira abordagem investiguei o padrão de integração morfológica das espécies a partir da comparação das variâncias e covariâncias dos caracteres. Os resultados evidenciam dois principais pontos. O primeiro é que houve uma considerável estabilidade na covariância entre caracteres ao longo de toda a história evolutiva de Carnivora, sugerindo a manutenção dos padrões de desenvolvimento no grupo como um todo. O segundo ponto é que, apesar desta estabilidade, espécies da família Canidae apresentam modificações em sua integração morfológica que os tornam mais similares entre si e mais dissimilares com os demais Carnivora. Essas diferenças estão relacionadas principalmente com caracteres da região facial, que apresentaram maior flexibilidade evolutiva, maiores correlações entre caracteres, e contêm uma maior proporção da variância em Canidae que nos demais Carnivora. Em uma segunda abordagem investiguei as propriedades estatísticas de dois testes baseados na teoria de genética quantitativa: o teste de regressão de autovalores e o teste de correlação de componentes principais (PCs). Estes testes avaliam a proporcionalidade entre padrões de covariância genética e entre-espécies como forma de testar a hipótese nula de deriva genética. Os resultados mostram que o uso de contrastes filogenéticos independentes (PIC) reduz erros do tipo I inflados, principalmente no caso do teste de correlação. Quando PIC são utilizados, o teste de correlação apresenta taxas de erro tipo I nominais para todos os números de espécies. Entretanto, a flutuação do número efetivo populacional (Ne) infla o erro tipo I deste testes. O teste de regressão, apesar de apresentar erro do tipo I inadequado para número de espécies baixo, é robusto a flutuações de Ne. A redução do número de PCs reduz o erro do tipo I a valores nominais à custa de uma redução no poder do teste. O poder de ambos os testes é similar nos diversos cenários avaliados, com uma leve tendência de maior poder para o teste de correlação em números amostrais mais baixos. Adicionalmente, as famílias de Caniformes foram utilizadas como estudo de caso para ambos testes. Os testes foram realizados com métodos paramétricos e não-paramétricos (simulações) e com e sem PIC. Houve rejeição de deriva para quase todas as famílias, com exceção de Mephitidae e Ursidae. Os testes de regressão baseados em simulações se mostraram consistentes com e sem o uso de PIC, apresentando intervalos de confiança menores que os testes paramétricos. Os resultados da presente tese abrem diversas possibilidades de investigação futura, tanto do ponto de vista empírico (em relação a modificações de Canidae e dos processos evolutivos deste grupo e de Ursidae e Mephitidae), assim como metodológicos (aprofundamento das investigações sobre as propriedades dos métodos para investigações macroevolutivas baseados em genética quantitativa) / The phenotype of complex characters is the end-product of the interrelations between genes, ontogenetic pathways and environmental effects. The variation in these factors influences not only the final phenotype, but also how characters covary and evolve in an integrated way. Natural selection can influence the interaction among characters, leading to changes in the patterns of integration. Therefore, a integrative and dynamic view of complex phenotypes is essential to the understanding of the evolutionary history of such structures. In the present thesis I investigated the morphological integration of cranial characters in Caniform species in two perspectives. In the first approach I investigated the pattern of morphological integration of the species through the comparison of character variances and covariances. The results of this investigation highlighted two points. The first is that there is considerable stability in the covariance among characters along the evolutionary history of Carnivora, suggesting the maintenance of ontogenetic pathways in the group. The second is that, despite this stability, Canidae species show changes in their morphological integration that make them more similar among each other and more different from the rest of Carnivora. These changes are related mainly to characters from the facial region, which showed a greater evolutionary flexibility, greater correlation among characters, and concentrate a greater proportion of the variance in Canidae than in the rest of Carnivora. In a second approach I evaluated the statistical properties of tests based on quantitative genetics theory: the test of regression of eigenvalues and the test of correlation of principal components (PCs). These tests investigate the proportionality between patterns of genetic and between-species covariance as a way to test the null hypothesis of genetic drift. The results show that the use of phylogenetic independent contrasts (PIC) reduces the inflated type I error, especially in the case of the correlation test. When PIC are employed, the correlation test shows nominal type I error rates for all species sample sizes. However, the oscillation of the effective population size (Ne) inflates type I error rates of these tests. The regression test, despite showing inadequate type I error rates at small species sample sizes, is robust to the oscillation of Ne. The reduction of the number of PCs reduces type I error rates to nominal values at the expense of statistical power. The power of both tests is similar under different scenarios evaluated, with a slight tendency of the correlation test to perform better at small number of species. Additionally, the Caniform families were used as case studies for both tests. Tests were performed using parametric and non-parametric (simulations) techniques, with and without PIC. The drift hypothesis was rejected for almost all families, with the exception of Mephitidae and Ursidae. The regression tests based on simulations were consistent with and without the use of PIC, showing narrower confidence intervals than the ones for parametric tests. The results of the present thesis open a wide range of future investigation opportunities, both from the empirical (relative to the differences in Canidae patterns of morphological integration or the evolutionary processes underlying Ursidae and Mephitidae diversification) and methodological (further investigations of the properties of the quantitative genetics-based tests for macroevolution) points of view

The distribution of the expressed genotype is moved around in the population over time byevolution. Natural selection is one of the forces that act on the phenotype to change the patterns ofnucleotide variation underlying those distributions. How the phenotype changes over aheterogeneous environment describes the type of evolutionary force acting on this trait and thisshould be reflected in the variation at loci underlying this trait. While the variation in phenotypesand at the nucleotide level in a population indicates the same evolutionary force, it does notnecessarily mean that they are connected. In natural populations the continuous shifting of geneticmaterial through recombination events break down possible associations between loci facilitates theexamination of possible causal loci to single base pair differences in DNA-sequences. Connecting thegenotype and the phenotype thus provides an important step in the understanding the geneticarchitecture of complex traits and the forces that shape the observed patterns.This thesis examines the European aspen, Populus tremula, sampled from subpopulations overan extensive latitudinal gradient covering most of Sweden. Results show a clear geneticdifferentiation in the timing of bud set, a measure of the autumnal cessation of growth, betweendifferent parts of Sweden pointing at local adaptation. In the search for candidate genes thatunderlie the local adaptation found, most genes (25) in the photoperiodic gene network wereexamined for signals of selection. Genes in the photoperiodic network show an increase in theheterogeneity of differentiation between sampled subpopulations in Sweden. Almost half (12) of theexamined genes are under some form of selection. Eight of these genes show positive directionalselection on protein evolution and the gene that code for a photoreceptor, responsible for mediatingchanging light conditions to downstream targets in the network, has the hallmarks of a selectivesweep. The negative correlation between positive directional selection and synonymous diversityindicates that the majority of the photoperiod gene network has undergone recurrent selectivesweeps. A phenomenon that likely has occurred when P. tremula has readapted to the northern lightregimes during population expansion following retracting ice between periods of glaciations. Two ofthe genes under selection also have single nucleotide polymorphisms (SNP) that associate with budset, two in the PHYB2 gene and one in the LHY2 gene. Furthermore, there is an additional SNP inLHY1 that explain part of the variation in timing of bud set, despite the lack of a signal of selection atthe LHY1 gene. Together these SNPs explain 10-15% of the variation in the timing of bud set and 20-30% more if accounting for the positive co-variances between SNPs. There is thus rather extensiveevidence that genes in the photoperiod gene network control the timing of bud set, and reflect localadaptation in this trait.

The ultimate goal of my thesis is to develop a better understanding of the contribution of indirect benefits (i.e. good genes) to the evolution of female mate preferences. It is genetic variance in, and genetic correlations (covariances) among, male sexual displays, female preferences for them, and fitness that in part determine the degree to which females preferring certain male displays over others will gain an indirect benefit by having higher fitness offspring. Recent advances in quantitative genetic theory provide the mathematical means for quantifying the strength of indirect selection for female mate preferences (Kirkpatrick and Hall 2004), at least under certain conditions, but there are few empirical systems for which such data exist (Brooks and Endler 2001; Qvarnström et al. 2006). I have undertaken a classic half-sibling breeding design with the ultimate goal of estimating the specific parameters of this model in a population of the Australian fruit fly Drosophila serrata. The breeding design was performed across two environments - one to which the population was well adapted and a novel environment to which it was not - thereby also providing insight into genotype-by-environment interactions for this suite of traits and their effects on good genes indirect benefits in a novel environment. General insight is also gained into the genetic covariance of male and female fitness and the prevalence of intralocus sexual conflict, the quantitative genetic basis of female mate preferences for multiple male traits, the condition-dependence of these traits, and the genetic association between sexual displays and fitness when mutation-selection balance is inferred. My results advocate caution in the application of existing theory to quantify the strength of indirect selection, suggesting that a good genes process may be fundamentally different when the exaggeration of sexual displays is eventually halted and an equilibrium is reached between opposing selection.

The ultimate goal of my thesis is to develop a better understanding of the contribution of indirect benefits (i.e. good genes) to the evolution of female mate preferences. It is genetic variance in, and genetic correlations (covariances) among, male sexual displays, female preferences for them, and fitness that in part determine the degree to which females preferring certain male displays over others will gain an indirect benefit by having higher fitness offspring. Recent advances in quantitative genetic theory provide the mathematical means for quantifying the strength of indirect selection for female mate preferences (Kirkpatrick and Hall 2004), at least under certain conditions, but there are few empirical systems for which such data exist (Brooks and Endler 2001; Qvarnström et al. 2006). I have undertaken a classic half-sibling breeding design with the ultimate goal of estimating the specific parameters of this model in a population of the Australian fruit fly Drosophila serrata. The breeding design was performed across two environments - one to which the population was well adapted and a novel environment to which it was not - thereby also providing insight into genotype-by-environment interactions for this suite of traits and their effects on good genes indirect benefits in a novel environment. General insight is also gained into the genetic covariance of male and female fitness and the prevalence of intralocus sexual conflict, the quantitative genetic basis of female mate preferences for multiple male traits, the condition-dependence of these traits, and the genetic association between sexual displays and fitness when mutation-selection balance is inferred. My results advocate caution in the application of existing theory to quantify the strength of indirect selection, suggesting that a good genes process may be fundamentally different when the exaggeration of sexual displays is eventually halted and an equilibrium is reached between opposing selection.

The general construct of human cognition implies a series of mental processes by means of which human interpret and consequently act on the world that surrounds them (Sternberg y Mio, 2009). During the last decades, the recognition of human diversity and psychological variability among individuals has encouraged challenging questions addressing inter-individual differences that make each subject unique in terms of their cognitive performance (Baddeley, 2003; Botvinick, 2008). In particular, quantitative genetic studies show that both genetic variability and environmental factors are involved in the phenotypic expression of cognitive functions (Plomin, 2011). However, the mechanisms by which genes and exposure to environmental influences may contribute to the observed variability are not yet clear. The study of the origins of inter-individual differences in cognition is strongly associated with the ontogenic development of the human brain (Tau, 2010). As a consequence, cognitive alterations are considered a central trait in those mental disorders where neurodevelopmental alterations are assumed to exist, such as schizophrenia. This disease, which affects around 1% of the world’s population, is one of the main causes of years lost due to disability (WHO, 2004), while cognitive alterations in these patients explain about 20%-60% of the variance in measures of outcome (Green, 2004). The aetiological model of neurodevelopment in schizophrenia proposes that this disease might be the expression of neurobiological compromise that could begin early in the lifespan, even before the onset of the clinical symptoms (van Os, 2009). However, and despite the scientific efforts invested in the elucidation of its aetiological underpinnings, the heterogeneous presentation of the disease has prevented a deeper comprehension of these mechanisms. Are all cognitive domains heritable? Are there long-term consequences on cognition for the early exposure to environmental impact? What is the association between genetic variability and cognitive vulnerability? Can we identify specific neurobiological pathways in the expression of the cognitive alterations of patients with schizophrenia? These questions are explored in the present thesis through the analyses of twins- and family-based samples, which constitute powerful designs to study the effects of genetic and environmental variability on human cognition. In the six chapters of results that are the body of this thesis, complex models are proposed that aim at representing the mechanisms involved in the origin of cognitive variability at the population level. The findings included indicate that this variability could be the result of the relative contribution of genetic determination and environmental modelling, which could vary in different cognitive functions following ontogenic mechanisms of neurodevelopment. Specifically, results are reported on the influences of childhood maltreatment and socioeconomic status as environmental stressors, as well as Val158Met functional polymorphism of COMT gene as a genetic factor. The aetiological implications of the study of these processes are extended to the field of mental disorders, as the results may indicate that the cognitive variability present among patients with schizophrenia could support a model of developmental compromise in this disease. Accordingly, the effects of genetic and environmental influences on behaviour may underlie the heterogeneous expression of this highly disabling mental disorder. To sum up, the phenotypic diversity of schizophrenia and human cognition, far from representing an obstacle, lays the foundations for complex models of these traits that may feed an increasing understanding of their aetiology (Belsky, 2011). These findings highlight the putative role of neurobiological liability traits in crucial aspects of clinical practice. Risk factors might be identified that could be included as potential guidelines in the assessment and management of need-adapted treatments (Leiftker, 2009). Moreover, liability traits might operate as markers in preventive interventions for targeting individuals at risk of developing particular forms of the disease (Keshavan, 2011). / El constructo general de cognición humana involucra una serie de procesos mentales por medio de los cuales los individuos perciben, interpretan y, en consecuencia, actúan sobre la realidad que los rodea y sobre sus pares (Sternberg y Mio, 2009). En los últimos años, el reconocimiento de la diversidad humana y la variabilidad de los rasgos psicológicos entre los individuos ha promovido preguntas acerca de las diferencias inter-individuales que hacen a cada sujeto único en términos de cognición (Baddeley, 2003; Botvinick, 2008). En particular, los estudios de genética cuantitativa demuestran que tanto la variabilidad genética como los factores ambientales podrían estar involucrados en la expresión fenotípica de las funciones cognitivas (Plomin, 2011). Sin embargo, aún no son claros los mecanismos específicos por medio de los cuales los genes y el ambiente contribuyen a esta variabilidad. Las alteraciones cognitivas son un rasgo central en enfermedades mentales donde se presume que existen alteraciones del neurodesarrollo, como lo es la esquizofrenia. El modelo etiológico del neurodesarrollo de la esquizofrenia propone que esta enfermedad se expresaría como consecuencia de alteraciones neurobiológicas que iniciarían en una época temprana de la vida, incluso antes del desencadenamiento de los síntomas clínicos (van Os, 2009). No obstante, la presentación heterogénea de la enfermedad ha dificultado una comprensión más clara de los mecanismos involucrados en su manifestación. ¿Son todas las funciones cognitivas igualmente heredables? ¿Tienen los factores ambientales tempranos consecuencias a largo plazo sobre la cognición? ¿Cuál es la relación entre variabilidad genética y vulnerabilidad cognitiva? ¿Existen vías neurobiológicas específicas para la manifestación de las alteraciones cognitivas en pacientes con esquizofrenia? Estas preguntas se exploran en la presente tesis a partir de análisis basados en muestras de gemelos y en grupos familiares, que constituyen una manera metodológicamente potente de estudiar los efectos de la variabilidad genética y ambiental sobre la cognición humana. En este sentido, la diversidad fenotípica de la esquizofrenia y la cognición humana, lejos de representar un obstáculo para la investigación de su etiología, sienta las bases de modelos complejos que podrían fomentar una comprensión cada vez más completa de los mecanismos de vulnerabilidad y resiliencia posiblemente involucrados en su origen (Belsky, 2011).

The ultimate goal of my thesis is to develop a better understanding of the contribution of indirect benefits (i.e. good genes) to the evolution of female mate preferences. It is genetic variance in, and genetic correlations (covariances) among, male sexual displays, female preferences for them, and fitness that in part determine the degree to which females preferring certain male displays over others will gain an indirect benefit by having higher fitness offspring. Recent advances in quantitative genetic theory provide the mathematical means for quantifying the strength of indirect selection for female mate preferences (Kirkpatrick and Hall 2004), at least under certain conditions, but there are few empirical systems for which such data exist (Brooks and Endler 2001; Qvarnström et al. 2006). I have undertaken a classic half-sibling breeding design with the ultimate goal of estimating the specific parameters of this model in a population of the Australian fruit fly Drosophila serrata. The breeding design was performed across two environments - one to which the population was well adapted and a novel environment to which it was not - thereby also providing insight into genotype-by-environment interactions for this suite of traits and their effects on good genes indirect benefits in a novel environment. General insight is also gained into the genetic covariance of male and female fitness and the prevalence of intralocus sexual conflict, the quantitative genetic basis of female mate preferences for multiple male traits, the condition-dependence of these traits, and the genetic association between sexual displays and fitness when mutation-selection balance is inferred. My results advocate caution in the application of existing theory to quantify the strength of indirect selection, suggesting that a good genes process may be fundamentally different when the exaggeration of sexual displays is eventually halted and an equilibrium is reached between opposing selection.

[Truncated abstract] Field pea (Pisum sativum) has many benefits when included in the crop rotation system in broadacre grain farming. These benefits include a disease break and improved weed control for cereals and less dependence on nitrogenous fertilisers due to the leguminous nature of pea. Currently, field pea adoption in Australia is low because the crop is susceptible to the fungal disease `black spot’ (Mycosphaerella pinodes) and has low stem strength and a lodged canopy. Black spot causes yield losses averaging 10-15% per year. Lodging results in difficult and costly harvesting, increased disease pressure and increased wind erosion from exposed soil surface when stems break at the basal nodes. This project aimed to address these problems through breeding, and through the application of quantitative genetics theory to a recurrent selection program. A quantitative measurement of relative stem strength was developed which could be used effectively in the field on single plants. Accurate laboratory measurements of stem strength were closely correlated with the field measure of compressed stem thickness in the basal node region. A diallel analysis of stem strength of the progeny of crosses among a range of pea lines with different values of compressed stem thickness concluded that the genetic control of stem strength was additive, with no maternal inheritance or dominance or epistasis effects.

L'adaptation locale est un phénomène micro-évolutif qui peut survenir lorsque des populations d'une même espèce sont exposées à des conditions environnementales différentes.Si cet environnement exerce une pression sous forme de sélection naturelle, qu'il existe un potentiel adaptatif au sein des populations et que le flux de gènes est suffisamment modéré, les populations vont alors tendre vers un optimum adaptatif local.Dans cette thèse, je m'intéresse aux moyens méthodologiques de l'étude de l'adaptation locale d'une part, et à l'étude de ce phénomène le long d'un gradient d'altitude chez la plante alpine Arabis alpina d'autre part.Dans la première partie méthodologique, je montre que les méthodes de scan génomique pour détecter les marqueurs génétiques sous sélection peuvent souffrir de forts taux de faux positifs lorsqu'exposées à des jeux de données complexes, mais réalistes.Je présente ensuite une méthode statistique de détection de marqueurs génétiques sous sélection qui, contrairement aux méthodes existantes, utilisent à la fois la notion de différentiation génétique (ou Fst) et une information environnementale.Cette méthode a été développée de manière à limiter son taux de faux positifs de manière générale.J'offre enfin une perspective concernant les liens entre une expérience ancienne en biologie évolutive (l'expérience de jardin commun) et les nouveaux développements moléculaires et statistiques modernes.Dans la seconde partie empirique, je présente une analyse de la démographie d'A. alpina dans six populations naturelles. Outre qu'elle révèle des caractéristiques biologiques intéressantes sur cette espèce (faible espérance de vie, reproduction et survie très différentielle...), cette analyse montre que la croissance diminue et la survie augmente chez cette espèce avec la baisse de la température moyenne (donc avec l'altitude).Puisque ces analyses ne permettent pas d'exclure des hypothèses de dérive et de plasticité phénotype, je présente une analyse en jardin commun sur A. alpina qui permet de lisser les problèmes de plasticité phénotypique et qui, combinée à des analyses moléculaires, permettent d'exclure l'hypothèse de dérive.Les résultats montrent qu'il existe un syndrome phénotypique adaptatif lié à la température moyenne qui tend à des plantes plus petites, plus compactes, qui croissent et se reproduisent moins, dans les milieux froids.À l'aide des données moléculaires et de méthodes de scan génomique, je présente une liste de 40 locus qui peuvent être impliqués dans ce processus.Pour finir, je discute l'ensemble de ces résultats empiriques dans un contexte plus général d'écologie alpine. Je résume ensuite les principaux obstacles méthodologiques à l'étude de l'adaptation locale et je fourni quelques perspectives méthodologiques. / Local adaptation is a micro-evolutionary phenomenon, which arises when populations of the same species are exposed to contrasted environmental conditions.If this environment exert some natural selection pressure, if an adaptive potential exists among the populations and if the gene flow is sufficiently mild, populations are expected to tend toward a local adaptive optimum.In this thesis, I study the methodological means of the study of local adaptation on the one hand, and I investigate this phenomenon along an elevation gradient in the alpine plant Arabis alpina on the other hand.In the first, methodological part, I show that the genome scan methods to detect selection using genetic markers might suffer strong false positive rates when confronted to complex but realistic datasets.I then introduce a statistical method to detect markers under selection, which, contrary to existing methods, make use of both the concept of genetic differentiation (or Fst) and environmental information.This method has been developed in order to reduce its global false positive rate.Finally, I present some perspectives regarding the relationships between the relatively old ``common garden'' experiment and the new developments in molecular biology and statistics.In the second, empirical part, I introduce an analysis of the demographic characteristics of A. alpina in six natural populations. Besides providing interesting biological information on this species (low life expectancy, strongly contrasted reproduction and survival...), these analyses show that growth increase and survival decrease with the decrease of average temperature (hence with altitude).Since these analyses do not allow us to rule out hypotheses such as drift and phenotypic plasticity, I show the results of a common garden experiment which enable us to smooth phenotypic plasticity and, when combined with molecular data, enable us to rule out the hypothesis of drift.The results show the existence of an adaptive phenotypic syndrome, in which plants are smaller, are more compact, grow slower and reproduce less in cold temperature environments.Using the molecular data, I draw a list of 40 locus which might be involved in this adaptive process.In the end, I discuss these empirical findings as a whole to place them in a more general context of alpine ecology. I sum up the main methodological challenges when studying local adaptation and offer some methodological perspectives.

Made available in DSpace on 2015-03-26T13:39:57Z (GMT). No. of bitstreams: 1 texto completo.pdf: 1146337 bytes, checksum: 9edc6a735d40be51b2865d311e2d3f55 (MD5) Previous issue date: 2013-07-16 / Conselho Nacional de Desenvolvimento Científico e Tecnológico / The objective of this study was to evaluate the quality of the forage and the silage fermentation profile made exclusively from Luziânia, Sambaíba, Tucunaré and UFV 16 cultivars. This profile was also made from UFVS 2003 of 10 intersections obtained from these cultivars and from the lineages TMG 801, tolerant to rust, UFVTN 105 AP, with high protein, and Vx 05-3027, Vx 05-3166 and Vx 05-3600, which are resistant to the Glyphosate herbicide action. The crosses were obtained from a complete diallel design, with fixed models and with the inclusion of parents and Fn s (method 2), as well carried out to the current generation.Two experiments were assembled with plants of F7 and F8 generations, in the years 2011/12 and 2012/13, respectively. Each selected plant in generation F7 consisted of a F8 generation line. The harvest occurred when the plants achieved the R6 stage for their silage, with the opening of the silos 60 days later. Forage chemical analyses before the silage were made at the Animal Nutrition Laboratory, in the Animal Science Department of the Federal University in Viçosa. Plant high and fresh mass were measured in generation F7, and the productivity of the dry mass was calculated per hectare. Dry and organic matter, ash, ethereal extract, crude protein, soluble carbohydrates, fiber in neutral and in acid detergent, and lignin in samples before and after the silage, are some of the things that were analyzed by the study.Ammonia nitrogen, pH and organic acids were analyzed just at the silage. As done in the generation F7, plant high and fresh mass were also measured in generation F8. The productivity of the dry mass was as well calculated. The variables were submitted to variance and diallelical analyzes, besides of the phenotypic, genotypic and environmental correlations between them. It was possible to obtain the populations that were favorable to the silage production and, consequently, to probable soybean cultivars, which are appropriated for this silage development. An example is the crossing between Sambaíba X Tucunaré, which brought together the most favorable characteristics, and showed that it is capable of generating increases in the CHOS tenor, and also of reducing the LIG, pH, N-NH3/NTotal, ACE tenors. At the same time this crossing is capable of raising the LAT and the UFV 16 X UFVS 2003 crossing conciliated a reduced tenor of EE and N-NH3/NTotal, with elevated CHOS tenor.UFV-TN 105 and Vx 05-3166 lineages conciliated elevated MS, PB, CHOS tenor and reduced RR tenor, showing that they are capable of being included in breeding programs, aiming the selection of soybean forage. / Procurou-se avaliar a qualidade de forragem e o perfil fermentativo da silagem exclusiva feita a partir dos cultivares Luziânia, Sambaíba, Tucunaré, UFV 16, UFVS 2003 dos 10cruzamentos obtidos a partir desses cultivarese das linhagens TMG 801 (tolerante à ferrugem), UFVTN 105 AP (alta proteína), Vx 05-3027(RR),Vx 05-3166(RR) e Vx 05-3600(RR), estes últimos resistentes à ação do herbicida Glyphosate. Os cruzamentos foram obtidos a partir de dialelo completo, com modelos fixos e a inclusão dos genitores e F1s(método 2), e realizados até a atual geração. Foram montados dois experimentos, com plantasdas gerações F7 e F8,nos anos agrícolas 2011/12 e 2012/13, respectivamente. Cada planta selecionada na geração F7 consistiu em uma linha da geração F8. O delineamento experimental foi o de blocos casualizados com três repetições. Cada parcela foi constituída de duas fileiras de 5 m, distantes entre si 0,7 m. A colheita ocorreuno estádio R6, para realização da ensilagem das plantas e posterior abertura dos silos 60 dias após. As análises bromatológicas da forragem antes daensilagem e da silagem foram realizadas no Laboratório de Nutrição Animal do Departamento de Zootecnia da Universidade Federal de Viçosa. Na geração F7 foram medidas a altura de plantas e massa frescacalculada a produtividade de massa seca por hectare. Foram analisados teores de matéria seca, matéria orgânica, cinzas, extrato etéreo, proteína bruta, carboidratos solúveis, fibras em detergente neutro, fibras em detergente ácido e lignina, tanto na silagem quanto na forragem. Nitrogênio amoniacal, pH e ácidos orgânicos foram analisados apenas na silagem. Na geração F8 foram medidas a altura de plantas e a massa fresca e calculada a produtividade de massa seca.As variáveis foram submetidas às análises de variância e análise dialélica,além da análise de correlações fenotípica, genotípica e ambiental entre elas. Foi possível a obtenção de populações favoráveis à produção de silagem e, consequentemente, de prováveis cultivares de soja apropriadas à produção de silagem, a exemplo dos cruzamentos Sambaíba x Tucunaré, que reuniram maior número de características favoráveis, mostrando-se capazes de gerar incrementos no teor de CHOS e reduzir os teores de LIG, pH, N-NH3/ NTotal, ACE e, ao mesmo tempo, elevar o teor de LAT; e UFV 16 x UFVS 2003 conciliou reduzido teor de EE e N-NH3/ NTotal, com alto teor de CHOS. As linhagens UFV-TN 105 e Vx 05-3166 conciliaram elevado teor de MS, PB, CHOs e reduzido teor de EE, mostrando-se passíveis de serem incluídos em programas de melhoramento visando à seleção de soja forrageira.