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This dissertation on emerging markets is driven by one fundamental question, i.e., is there any association between accounting data and market values in high risk and volatile emerging markets. To this end, two models, residual incomevaluation (R.I.M) and abnormal earnings growth (A.E.G), have been explored in this work.In the first study, a model of type Residual Income Valuation is developed and its implications are empirically tested on sample consisting of American companies, developed countries apart from USA and emerging countries over the period2000-2007. The results show that in most of countries studied, the association between the book value and market value ofequity significantly depends on the stage of growth and the method of financing characterizing the company.The development of a valuation model of type Abnormal Earnings Growth Model ( by Ohlson & Juettner-Nauroth),including modeling of evolution of expected relationship between market value of a share, expected earnings per share in ayear, its rate of growth in short-term and a set of accounting variable composing a synthetic indicator of growth of company,is studied in the second research work of this dissertation. Our results show that (1) expected increase in earnings per shareare significantly associated with stock prices ( especially for developed countries), (2) but, as suggested by our model, the persistence of its effects is limited ( especially for emerging countries), (3) when the dynamics of growth are more complex,inclusion of a synthetic variable can make a significant correction term (4) and finally the implied cost of capital issignificantly higher for emerging countries than for developed countries; Cette thèse de doctorat s’intéresse fondamentalement au traitement de la question suivante : quelle forme d’association entre les données comptables et les valeurs de marché subsiste dans le contexte de forte volatilité et de haut risque propre aux marchés émergents ? Pour atteindre ce but, deux modèles ont été utilisés dans ce travail : le modèle d’évaluation par les résultats résiduels (ou residual income model R.I.M) et celui de l’évaluation par la croissance anormale des résultats (ou abnormal earnings growth A.E.G).Dans cette étude, un modèle de type R.I.M. est développé avec des hypothèses particulières concernant la capacité de l’entreprise à créer de la valeur et ses implications ont été testées empiriquement sur un échantillon comprenant des entreprises provenant d’Amérique du Nord, d’autres pays développés et d’un ensemble de pays émergents sur la période2000-2007. Les résultats obtenus soulignent que le degré d’association entre les valeurs comptables et les valeurs de marché dépend du stade de croissance et des modes de financement utilisés par les firmes. Si les indicateurs comptables de croissance et d’endettement apportent une information complémentaire significative dans les pays développés, leur contribution est très modeste dans le cas des pays émergents.Le développement d’un modèle d’évaluation de type AEG (initialement proposé par Ohlson & Juettner-Nauroth), incluant une modélisation de l’évolution des rentes attendues compatible avec des conditions de concurrence pure et parfaite nous permet de proposer une relation testable entre la valeur de marché d’une action, le résultat net par action attendu dans un an,son taux de croissance à court terme et un ensemble de variables comptables composant un indicateur synthétique de croissance de l’entreprise. Nos résultats montrent (1) que l’accroissement attendu du bénéfice par action est associé significativement au cours boursier (surtout pour les pays développés), (2) mais que, comme le suggère notre modèle, la persistance de ses effets est limitée (surtout pour les pays émergents), (3) que lorsque la dynamique de la croissance est plus complexe, l’inclusion d’une variable synthétique apporte un terme correctif significatif (4) et enfin que le coût du capital implicite est sensiblement plus élevé pour les pays émergents que pour les pays développés

International audience; Marker informed breeding could be a favorable opportunity to accelerate cultivar selection in poplar. Linking genotype to phenotypic variation of important economical and adaptive traits is the prerequisite. The two strategies chosen are QTL detection in mapping pedigrees and association studies in natural populations. An intra-specific mapping pedigree Populus nigra x P. nigra of 300 individuals segregating for leaf rust resistance is available. Another large progeny of 1400 individuals derived from a cross P. deltoides x P. trichocarpa for which two major factors and QTL of rust resistance segregated is already available. QTL for phenology and water use efficiency were also mapped. Large scale phenotyping of wood properties is underway. An association mapping population of 1100 P. nigra individuals coming from France, Germany, Netherlands and Spain was evaluated for rust resistance in both controlled and field conditions. Even if most of the genetic variation for rust resistance could be observed at the genotype level, significant differentiation between natural populations was detected. Taking advantages of genomics development in poplar including structural and functional genomics, positional, functional and expressional candidate genes were identified for rust resistance, phenology and wood properties. It became clear that SNP in those genes could be ideal combined to HTP genotyping technologies to identify causative polymorphism for phenotypic variation. We developed collections of SNP useful for both genetic and association mapping. With the help of the genome sequence, unique primer pairs were automatically designed and tested for their uniqueness before PCR amplification and HTP Sanger re-sequencing. Based on the analysis of 850 gene fragments, an average of 1SNP/90bp were found in the three Populus species studied. SNP appeared fixed in each species after comparison of SNP position between the three species. Analysis of linkage disequilibrium in P. nigra showed a rapid decline of LD with physical distance

Association studies aim at linking phenotypic variation with allelic variation in candidate genes and benefit from several generations of recombination in natural populations to identify causative polymorphisms. Such association studies are under development on Populus nigra L., with emphasis on nucleotide polymorphism associated to quantitative resistance to Melampsora larici-populina Kleb (Mlp), the causal agent of leaf rust. Populus nigra, the natural host of Mlp, is widely represented in European riparian ecosystems, where the occurrence and impact of the fungus are highly variable. Geographical patterns of nucleotide diversity in genes involved in the host-pathogen interaction is expected from local co-evolution. As a first step, Single Nucleotide Polymorphisms (SNPs) have been identified in a discovery panel of twenty-one P. nigra genotypes covering French natural range. Sequencing was done on both functional and positional candidate resistance genes (closeness to mapped QTLs and resistance genes). An automated procedure for primer design allowed us to obtain successful amplification in P. nigra for 90% of gene fragments. Average nucleotide variation in P. nigra is high (1 SNP/97 pb). A collection of more than 1100 P. nigra genotypes collected in different natural populations mainly in France but also in Germany, Netherlands, Italy and Spain was evaluated for rust resistance under natural inoculation in a clonal test in France and under artificial inoculations with different strains in leaf-disk bioassays. Even if most of the genetic variation for rust resistant could be observed at the individual (genotype) level, significant differentiation between natural populations was detected. The high level of genetic diversity observed at both gene and phenotypic levels, the rapid linkage disequilibrium decay between SNP is offering a favourable situation to identify interesting resistance alleles and to avoid false positive associations.