A mon frère Benjamin… TABLE DES MATIÈRES Table des matières LISTE DES ABRÉVIATIONS.......................................................................................... 1 INTRODUCTION GÉNÉRALE........................................................................................ 3 I. LA VANILLE : DONNEES AGRONOMIQUES .......................................................................... 3 II. LA VANILLE : DONNEES ECONOMIQUES ........................................................................... 5 III. LA VANILLE : INTERET DES RESSOURCES GENETIQUES............................................................ 7 IV. PROBLEMATIQUE ET OBJECTIFS DE LA THESE .................................................................... 8 CHAPITRE 1 : INTRODUCTION BIBLIOGRAPHIQUE .......................................................... 10 I. PREAMBULE ..................................................................................................... 10 Article N°1 : Biodiversity and preservation of vanilla: present state of knowledge ..... 11 Abstract ................................................................................................................ 12 Introduction ........................................................................................................... 12 Vanilla taxonomy and phylogeny .................................................................................. 13 Vanilla within the Orchidaceae................................................................................. 13 Distribution ................................................................................................................... 13 Taxonomy and phylogeny ................................................................................................... 13 The Vanilla genus ................................................................................................. 14 The genus organization...................................................................................................... 14 Phylogenetic relationships among Vanilla species ...................................................................... 19 The origin of V. tahitensis .................................................................................................. 20 Reproductive biology ................................................................................................ 21 The reproduction of American vanilla in natural conditions .............................................. 21 Inter-specific hybridization ..................................................................................... 22 V. planifolia in its area of origin................................................................................... 22 The history of V. planifolia in Mexico ......................................................................... 22 Vanilla diversity in Mexico ...................................................................................... 23 V. planifolia in introduction areas................................................................................. 24 V. planifolia dissemination from its area of origin ......................................................... 24 V. planifolia diversity in introduction areas ................................................................. 24 Phenotypic diversity in Reunion Island........................................................................ 24 Possible origins of this phenotypic diversity................................................................. 26 Preservation of vanilla genetic resources ........................................................................ 28 Conclusions ............................................................................................................ 29 References............................................................................................................. 30 II. CONCLUSIONS DE L’INTRODUCTION BIBLIOGRAPHIQUE ......................................................... 33 CHAPITRE 2 : ANALYSE GÉNÉTIQUE........................................................................... 35 I. PREAMBULE ..................................................................................................... 35 I Table des matières Article N°2 : Patterns of introduction and diversification of Vanilla planifolia (Orchidaceae) in Reunion Island (Indian Ocean) .................................................... 37 A2.1. Abstract......................................................................................................... 39 A2.2. Introduction.................................................................................................... 39 A2.3. Materials and methods ....................................................................................... 43 A2.3.1. Plant material and DNA extraction .................................................................. 43 A2.3.2. AFLP assay................................................................................................ 44 A2.3.3. Data analysis............................................................................................. 45 A2.3.4. Reproducibility.......................................................................................... 46 A2.4. Results .......................................................................................................... 46 A2.4.1. Interspecific AFLP diversity ........................................................................... 46 A2.4.2. Intraspecific AFLP diversity ........................................................................... 47 A2.5. Discussion ...................................................................................................... 49 A2.5.1. Patterns of introduction of V. planifolia in Reunion Island...................................... 49 A2.5.2. V. pompona: another case of a limited introduction event in Reunion Island................ 50 A2.5.3. Patterns of diversification of V. planifolia in Reunion Island ................................... 51 A2.5.4. Perspectives for vanilla breeding .................................................................... 54 A2.5.5. Conclusions .............................................................................................. 54 Acknowledgements................................................................................................... 56 Article N°3 : Development of microsatellite markers in cultivated vanilla: polymorphism and transferability to other Vanilla species......................................................... 57 Abstract ................................................................................................................ 58 1. Introduction ........................................................................................................ 58 2. Materials and methods ........................................................................................... 59 3. Results .............................................................................................................. 61 4. Discussion........................................................................................................... 61 Acknowledgements................................................................................................... 62 References............................................................................................................. 62 II. APPORT COMPLEMENTAIRE DES MICROSATELLITES POUR L’ANALYSE GENETIQUE ............................... 64 II.1. Introduction ..................................................................................................... 64 II.2. Matériel et méthodes .......................................................................................... 65 II.2.1. Matériel végétal .......................................................................................... 65 II.2.2. Analyse microsatellite................................................................................... 66 II.3. Résultats ......................................................................................................... 67 II.3.1. Précisions des résultats de l’analyse AFLP : identification des échantillons inconnus (SP).. 67 II.3.2. Intérêt du marqueur mVplCIR031 pour la phylogéographie ....................................... 69 II.4. Discussion ........................................................................................................ 70 II.4.1. Diversité intraspécifique................................................................................ 70 II.4.2. Hybrides artificiels....................................................................................... 71 II.4.3. Mise en évidence du rôle de l’hybridation dans l’évolution du genre Vanilla.................. 71 II.4.4. Accessions restantes non identifiées .................................................................. 72 II.4.5. Phylogéographie dans le genre Vanilla................................................................ 73 III. CONCLUSIONS DE L’ANALYSE GENETIQUE ...................................................................... 75 II Table des matières CHAPITRE 3 : ANALYSE CYTOGÉNÉTIQUE.................................................................... 77 I. PREAMBULE ..................................................................................................... 77 Article N°4 : Natural polyploidy in Vanilla planifolia (Orchidaceae).......................... 79 A4.1. Abstract........................................................................................................