The evolutionary relevance of homeotic alterations for the origin of new taxonomic entities is still a controversial objective in plant sciences. In this context, the discovery of a floral homeotic variant of Capsella bursa-pastoris in natural populations offers the unique opportunity to elucidate the evolutionary significance of homeotic mutants in the wild. Since all petals are transformed into additional stamens, the variant was termed Stamenoid petals (Spe). In this thesis, a combination of ecological and molecular characterisation of the variant was performed, to improve the understanding of evolutionary processes in plant populations. Molecular markers were used to analyze genetic differentiation among known provenances and also within a large sympatric population of wild-type and homeotic mutant. The results clearly suggest a repeated evolution of the novel flower morphology. Furthermore, genetic analyses provided substantial evidence, that the two floral variants are well-defined into flower-type dependent sub-samples within one population. The evaluation of phenotypic traits elucidated that the homeotic variant is not hampered in fitness. In greenhouse and field experiments, a significant ecological differentiation in the onset of flowering was detected among variants. Finally, the novel floral phenotype shows a co-dominant inheritance, and a marker-assisted mapping approach exposed a single locus in a genetic map. In conclusion, the comprehensive study of ecological and molecular aspects indicates that the floral homeotic variant may be treated as an established taxonomic entity and proved the predicted role as model for evolutionary objectives. Since morphological alterations like Spe are discussed as a result of macroevolution, the homeotic variant of C. bursa-pastoris provides the opportunity to survey a (macro)evolutionary novelty in association with continuous micro-evolutionary adaptation

No description available.

No description available.

Future global change scenarios predict a dramatic loss of biodiversity for many regions in the world, potentially reducing the resistance and resilience of ecosystem functions. Once before, during Plio-Pleistocene glaciations, harsher climatic conditions in Europe as compared to North America led to a more depauperate tree flora. Here we hypothesize that this climate driven species loss has also reduced functional diversity in Europe as compared to North America. We used variation in 26 traits for 154 North American and 66 European tree species and grid-based co-occurrences derived from distribution maps to compare functional diversity patterns of the two continents. First, we identified similar regions with respect to contemporary climate in the temperate zone of North America and Europe. Second, we compared the functional diversity of both continents and for the climatically similar subregions using the functional dispersion-index (FDis) and the functional richness index (FRic). Third, we accounted in these comparisons for grid-scale differences in species richness, and, fourth, investigated the associated trait spaces using dimensionality reduction. For gymnosperms we find similar functional diversity on both continents, whereas for angiosperms functional diversity is significantly greater in Europe than in North America. These results are consistent across different scales, for climatically similar regions and considering species richness patterns. We decomposed these differences in trait space occupation into differences in functional diversity vs. differences in functional identity. We show that climate-driven species loss on a continental scale might be decoupled from or at least not linearly related to changes in functional diversity. This might be important when analyzing the effects of climate-driven biodiversity change on ecosystem functioning.

The Earth harbors around 300 000 plant species. The rich and complex environment provided by plants is considered a key factor for the extraordinary diversity of the terrestrial fauna by, for example, providing food and shelter. This thesis contributes to the understanding of these questions by investigating how the interplay of physiology, demography, and evolution gives rise to variation and diversity in fundamental plant traits. This will help us answer questions such as: How has this amazing diversity of plant species emerged? Which mechanisms maintain diversity? How are plant strategies and plant diversity influenced by variations in the environment? A plant faces multiple problems to survive and reproduce successfully. These problems can be modeled by considering traits, trade-offs and a fitness measure. For example: How to maximize growth rate, while maximizing structural stability? I will investigate four plant models in order to understand the function of plants, and mechanisms promoting diversity.  Paper I: We study how annual plants with and without growth constraints should optimize their flowering time when productivity or season length changes. With a dynamic ontogenetic growth model and optimal control theory we prove that a bang-bang reproductive control is optimal under constrained growth and constant mortality rate. We find that growth constraints can flip the direction of optimal phenological response for increasing productivity. The reason is that the growth rate of vegetative mass saturates at high productivity and therefore it is better to flower earlier and take advantage of a longer reproductive period. If season length extends equally both in the beginning and the end of the season, growth constraints control the direction of the optimal response as well. Our theory can help explaining phenological patterns along productivity gradients, and can be linked to empirical observations made on a calendar scale. Paper II: We introduce a new measure of tree crown-rise efficiency based on the loss of biomass of the tree during growth. The more mass the tree looses during growth, the less crown-rise efficient it is. Top-heavy shapes loose more biomass than bottom-heavy shapes. Light-use efficiency is defined as the mean light assimilation of the leaves in the crown times the ratio of leaf mass and total mass. We then study the trade-off between light-use efficiency to crown-rise efficiency for tree crown shapes. We assume that the total tree mass is constant, and a constant vertical light gradient represent the shading from a surrounding forest. We find large differences in crown shapes at intermediate vertical light gradient, when both self-shading and mean-field shading are important, suggesting light-use vs crown-rise efficiency as a new trade-off that can explain tree diversity. Our crown-rise efficiency measure could easily be integrated into existing forest models. Paper III: We extend an evolutionary tree crown model, where trees with different heights compete for light, with drought-induced mortality rates depending on ground-water availability and the depth of an optional taproot. The model does not include competition for ground water. Our model explains how ground-water availability can shape plant communities, when taproot and non-taproot strategies can coexist, and when only one of these strategies can persist. We investigate how emerging plant diversity varies with water table depth, soil water gradient and drought-induced mortality rate. The taproot enables plants to reach deep water, thus reducing mortality, but also carries a construction cost, thus inducing a trade-off. We find that taproots maintain plant diversity under increasing drought mortality, and that taproots evolve when groundwater is accessible at low depths. There are no viable strategies at high drought mortality and deep water table. Red Queen evolutionary dynamics appear at intermediate drought mortality in mixed communities with and without taproots, as the community never reaches a final evolutionarily stable composition. Paper IV: We extend a size-structured plant model, with self-shading and two evolving traits, crown top-heaviness and crown width-to-height ratio. The model allows us to identify salient trade-offs for the crown shape. The most important trade-off for top-heaviness is light-use efficiency vs crownrise efficiency, and the most important trade-off for width-to-height ratio is self-shading vs branch costs. We find that when the two traits coevolve; the outcome is a single common evolutionarily stable strategy (ESS), far away from the highest net primary production (NPP). When only sun angle is decreasing with increasing latitude both the crown width-to-height ratio and crown top-heaviness decrease. However, when light response in addition to the sun angle decreases with increasing latitude, the crown width-to-height ratio is nearly invariant of latitude except at low site productivity when the ratio decreases with latitude. Top-heaviness is always decreasing with increasing latitude. Finally, we find that crown top-heaviness increases with the NPP or leaf-area index (LAI) at ESS, but crown width-to-height ratio is maximal at an intermediate NPP or LAI. / Artikel I: Arters reproduktionsframgång (fitness), till exempel antal avkommor eller frön som produceras under livet, är ofta avgörande för huruvida de är evolutionärt framgångsrika eller inte. Här undersöker vi hur ettåriga växter med eller utan tillväxtbegränsningar ska optimera sin blomningstid när produktivitet eller säsongslängd ändras. Det är optimalt att gå direkt från tillväxt till blomning när tillväxten är begränsad och dödligheten är konstant. Vid ökad produktivitet sker blomningen tidigare med tillväxtbegränsningar men senare utan tillväxtbegränsningar, vilket beror på att med tillväxtbegränsningar ökar den vegetativa massan långsamt. Därför är det bättre att blomma tidigare och ta tillvara på en längre reproduktionsperiod. Vi får samma resultat om säsongslängden ökar lika mycket i början och slutet av säsongen. Vår teori kan bidra till att förutsäga blomningstider vid produktivitetsförändringar och säsongsförändringar. Artikel II: Tillväxten hos träd kan begränsas av brist på ljus, vatten, och näring, men också genom förlust av grenar. Vi introducerar ett nytt mått på tillväxteffektiviteten hos trädkronor baserat på förlust av biomassa under trädets tillväxt. Ju mer massa trädet förlorar under tillväxt, desto mindre tillväxteffektiva är de. Topptunga former förlorar mer biomassa än bottentunga former. Vi studerar avvägningar mellan ljuseffektivitet och tillväxteffektivitet för trädformer, där ljuseffektiviteten definieras som medelljusupptaget för löven i kronan. Vi antar en konstant totalmassa, och en statisk vertikal skuggning som representerar skuggningen från en omgivande skog. Vi hittar stora skillnader i kronformer vid en medelhög skuggning, då både självskuggningen och medelskuggningen har betydelse. Vårt mått för tillväxteffektivitet kan enkelt integreras i existerande skogsmodeller. Studien visar att avvägningar mellan tillväxteffektivitet och ljuseffektivitetet kan vara viktig för mångfalden av trädformer i en skog. En överraskande upptäckt är att konformade eller sfäriska trädkronor aldrig är effektiva, men däremot timglasformade kronor. Artikel III: Växter kan försvara sig på olika sätt mot torka, till exempel genom att rulla ihop bladen eller genom att reproducera tidigare och därigenom undvika uttdragen torka. Här undersöker vi fördelarna med en pålrot vid torka. En pålrot är en rot som växer nedåt för att nå djupliggande grundvatten. Vi utvidgar en evolutionär modell av trädkronor med grundvatten och en pålrot, där träd med olika höjd konkurrerar om ljus. Det finns ingen konkurrens om vatten. Vi undersöker hur mångfalden hos träden beror på vattendjup, vattengradient och dödlighet orsakad av torka. Med hjälp av pålroten kan träden nå djupt vatten och därigenom minska dödligheten, men den medför också en kostnad, så en avvägning måste göras. Vi ser att pålrötter upprätthåller mångfalden hos växterna vid ökad mortalitet, och att pålrötter uppstår när grundvattnet är grunt. Det finns inga strategier som kan överleva om grundvattnet är djupt och dödligheten är hög. Vår modell kan förklara hur grundvatten kan förändra sammansättningen på trädsamhällen, när träd med och utan pålrot kan samexistera, och under vilka förutsättningar endast en av strategierna förväntas dominera. Artikel IV: Träd som växer upp i en skog måste konkurrera med andra träd om ljus, framförallt större träd. Detta ger upphov till en asymmetrisk ljuskonkurrens, där de små träden hämmas av större träd. Små träd har därmed små chanser att överleva utom då skogen nyligen störts och det öppnas upp en glänta. Vid denna ljuskonkurrens kan man anta att trädkronans form har stor betydelse för trädets framgång. Frågan är hur de evolutionärt fördelaktiga kronformerna beror på latituden och produktiviteten. Vi antar att latituden påverkar solens genomsnittliga vinkel och ljusrespons. Vi utvidgar en storleksstrukturerad trädmodell med självskuggning där två evolverande egenskaper beskriver kronans topptyngd och bredd. Med modellen kan vi undersöka vilka strategiska avvägningar som bestämmer om kronans form blir konkurrenskraftig. En topptung krona har högt ljusupptag eftersom det finns mest ljus högt upp i grenverket. Å andra sidan har den en låg tillväxteffektivitet eftersom topptunga kronor måste tappa mycket grenar för att behålla sin form. En bred krona har en låg självskuggning eftersom bladen är utspridda. Å andra sidan har den höga kostnader för de långa grenar som krävs. Vi finner att när dessa egenskaper evolverar tillsammans så finns endast en evolutionärt stabil strategi (ESS), långt från den högsta nettoproduktionen. När endast solvinkeln minskar med ökande latitud minskar både kronans bredd och topptyngd, men när både solvinkel och ljusrespons minskar med ökande latitud så är bredden nästan oförändrad utom vid låg produktivitet då den minskar med latituden. Kronans topptyngd minskar alltid med latituden. Slutligen ser vi hur kronans topptyngd alltid ökar med nettoproduktionen vid ESS, medan kronans bredd har ett maxium för ett mellanvärde hos nettoproduktionen vid ESS.

L'évolution climatique a été marquée ces dernières décennies par des changements importants, notamment une augmentation de température et une variation de la pluviométrie. Une des conséquences du changement climatique est son impact actuel et futur sur l'agriculture et la sécurité alimentaire. En région sahélienne, la sécurité alimentaire repose essentiellement sur quelques céréales, parmi lesquelles le mil occupe une place fondamentale. Un des traits qui permettent l'adaptation au climat de cette espèce est la date de floraison, dont la variation permet d'accomplir le cycle de vie de la plante dans des saisons pluvieuses plus ou moins courtes. Les bases génétiques de ce caractère adaptatif sont encore peu connues. Nous avons développé une méthodologie de cartographie d'association phénotype-génotype, afin d'identifier des gènes impliqués dans la variation de ce caractère. Cette étude a permis d'identifier deux gènes candidats, PHYC et MADS11, associés à la date de floraison et à la variation morphologique chez le mil. Nous avons validé ces associations par des analyses QTLs. Pour PHYC, nous avons aussi étudié le pattern de déséquilibre de liaison sur une zone d'environ 80 kb autour du gène, et développé une approche de Markov Chain Monte Carlo (MCMC) pour comparer les gènes identifiés dans la région. Cette analyse suggère que les polymorphismes à l'intérieur de PHYC sont les meilleurs candidats expliquant l'effet phénotypique observée dans cette région du génome. La seconde partie de ce projet a été consacrée à l'examen méthodologique de la cartographie d'association pour l'étude des interactions entre le génotype et l'environnement. Les résultats de cette thèse ont été discutés notamment dans la perspective de gestion de l'impact du changement climatique sur le mil, céréale majeure des zones semi-arides / In last decades, climate changes led to temperature increase and rainfall variation across the globe. One of the key consequences of these changes is their impact on agriculture and food security. In sahelian countries, food security relies on a few cereal crops, among which pearl millet plays a crucial role for population food supply. Sahel region is facing the impact of rainfall variability and drought since the 1970s. Flowering time variation is one of the main adaptations that allow pearl millet cultivation in drier and shorter rainy seasons. The genetic bases of this complex trait are still understudied. We developed an association mapping framework for the analysis of genotype-phenotype relationship in pearl millet. We successfully identified two genes associated with flowering time variation in pearl millet (PHYC and MADS11). We confirmed these associations using QTL studies. For PHYC, we also examined the pattern of linkage disequilibri um on a chromosomal region extending to 80 kb around the gene, and we developed a Markov Chain Monte Carlo approach (MCMC) to compare six genes identified in this region. Our results suggest that, among the polymorphisms observed in this region, polymorphisms in PHYC are the best candidate for a direct causative role. The second part of this project addressed methodological examination of association mapping framework to deal with genotype by environment interactions. The results of this work were discussed with regard to the challenge of pearl millet crop adaptation to climate change.

La perspective de la culture de variétés transgéniques pose, pour de multiples raisons, le problème de la ségrégation de filières de production basées sur la même espèce dans les paysages agricoles : demande d'une filière « sans OGM » ; coexistence de productions alimentaires et non alimentaires… La réglementation européenne fixe un seuil de présence fortuite d'OGM au-delà duquel un produit, même issu d'une variété non-OGM, doit être étiqueté comme contenant des OGM. La Commission européenne a émis des recommandations sur l'adoption de pratiques favorisant la coexistence entre cultures OGM et non-OGM de façon à ce que les agriculteurs puissent garder la liberté de choisir le mode de production qu'ils souhaitent. Dans ce contexte, il est important de pouvoir estimer a priori le taux d'impuretés OGM dans les récoltes de parcelles non-OGM, en fonction de leur organisation spatiale et du climat, mais aussi de comprendre et prédire l'effet de modifications de pratiques agricoles sur ce taux. L'expérimentation peut apporter des éléments de connaissances des phénomènes, la modélisation s'avère cependant plus pertinente pour répondre aux demandes d'aide à la décision (principalement publique) pour des situations agricoles et climatiques diversifiées. L'objectif de la thèse est donc de dégager un cadre méthodologique générique pour le développement de modèles de flux biologiques combinant de façon dynamique modélisation, évaluation et expérimentation. Le travail de thèse a consisté en la conception et l'évaluation du modèle MAPOD qui simule les flux de gènes chez le maïs à l'échelle du paysage. Ce modèle est basé sur une fonction de dispersion individuelle qui dépend de paramètres biologiques et climatiques et qui calcule une probabilité de fécondation en un point (x, y) en fonction de la distance à la source émettrice de pollen (pollinisation efficace). Il comporte un module de dynamique de floraison qui rend compte des conséquences des synchronismes ou asynchronismes de floraison entre champs sur les taux d'OGM dans les récoltes. Le modèle permet de déterminer l'effet de la distribution spatiale des parcelles de maïs, des caractéristiques variétales, du climat et des itinéraires techniques sur les taux de pollinisation croisée. MAPOD a été mis au point à partir de données de la littérature et d'expérimentations menées par le GEVES. Cette première version a été évaluée grâce à un second jeu de données provenant du GEVES. Elle a aussi fait l'objet d'une analyse de sensibilité. Les résultats obtenus ont permis de définir les pistes d'amélioration de l'algorithme. La qualité prédictive de MAPOD a ensuite été estimée grâce à des données issues de suivis effectués pendant 5 ans dans des parcelles d'agriculteurs en Catalogne, région où le maïs Bt est cultivé à grande échelle. La pertinence des décisions prises grâce aux sorties du modèle a aussi été caractérisée. MAPOD a été utilisé pour simuler différents scénarios d'introduction de variétés OGM dans les systèmes de culture européens. L'efficacité de mesures individuelles de coexistence a été testée. Ensuite, c'est l'effet de combinaison de pratiques qui a été simulé, aboutissant à l'établissement de tables de décision en fonction du contexte de culture. À l'échelle du bassin de collecte, l'efficience des stratégies de ségrégation (spatiale, temporelle) pouvant être mises en place par les organismes de collecte-stockage a aussi été étudiée grâce au modèle. Enfin, les sorties de MAPOD ont servi comme support pour la mise au point d'un outil d'aide à la décision à destination des agriculteurs et de leurs conseillers. / Consumer demand for food free of GMOs is growing and if production standards are to be met, food and non-food chains must be separated. Indeed, European Commission regulations 1829/2003 and 1830/2003 stipulate that food and feed thought to be GMO-free but found to be containing more than a 0.9% portion of an adventitious presence of authorized GMOs have to be distinguished, traced and labelled as such. Moreover, to ensure that producers have a choice a choice among differing types of production, the European Commission has issued recommendations that permit the coexistence of non-GM and GM crops. This poses the problem of how to deal with coexistence in an agricultural supply chain dedicated to handling a single crop species. To help in the elaboration of coexistence rules, and then assess their feasibility and their consequences as well as for setting up monitoring and control schemes, specific field experiments, even if necessary, are not sufficient as their predictive value remains restricted to a given context. It is necessary to be able to forecast the fate of GM crops at the landscape level taking into account the various cropping systems and agricultural practices that may occur across Europe. The key to forecasting spread and behaviour of GM plants and seeds as well as their impacts under a wide range of agro-ecosystems is modelling. Models reproduce the functioning of agro-systems and take into account the relevant factors and processes as well as their interactions. They thus make it possible to simulate the behaviour of agro-systems in non-observed situations and on a long term basis.This doctoral thesis establishes a methodological framework for the development of biological flow models thanks to the dynamic interactions of modelling, evaluation and experimentation. In a first phase, the work involved the design of the MAPOD® model developed in relationship to literature and varietal experiments carried out by GEVES. MAPOD® simulates gene flow between maize crops at the landscape scale. It is based on an individual dispersal function which depends on biological and climatic parameters. It calculates the probability of fecundation at a (x, y) point as a function of distance from the pollen emitter (efficient pollination). Its flowering dynamics module makes it possible to take into account of the consequences of flowering time - lags on GM adventitious presence in harvests. MAPOD® evaluates the effect of the spatial distribution of maize plots, varietal characteristics, and climate as well as agricultural practices on cross-pollination. In this investigation, in a second phase the initial version of MAPOD® was evaluated with another dataset provided by GEVES. Ways to improve the algorithm were thereby defined. In a third phase, the predictive quality of MAPOD® was estimated by comparing model outputs to cross-pollination rates which were obtained by monitoring farmers' fields in Catalonia (Spain) over a 5-year period. The relevance of decisions made according to model output was also evaluated.In a fourth phase, MAPOD® was used to simulate different scenarios involving the introduction of GM varieties into European cropping systems. The efficiency of individual coexistence measures was tested. Afterwards, the effect of combining different types of practices was simulated, leading to a set of decision-support tables elaborated according to the cropping context. At the scale of the collecting basin, with the enhanced version of MAPOD®, the efficiency of segregation strategies (spatial or temporal) that could be implemented by collecting and storing organisations was also studied. Lastly, model outputs were used as a basis for the design of a decision-support tool for use by farmers and extension workers.

Aujourd'hui, alors que le nombre de marqueurs génétiques disponibles augmente rapidement, de nouvelles populations doivent être créées pour exploiter au mieux cette quantité d'informations dans le but de mieux comprendre l'architecture génétique de caractères complexes. Les populations de type MAGIC ont été créées pour rassembler les avantages des populations bi-parentales et des panels d'associations, la bonne puissance de détection et une localisation précise. L'objectif de cette thèse était d'étudier l'intérêt de la population MAGIC INRA pour l'analyse de l'architecture génétique de la précocité de floraison. Cette population a été créée à partir de 60 parents brassés durant 12 générations de panmixie grâce à l'introduction d'un gène de stérilité mâle (ms1b). Cette étude a été réalisée sur 56 parents toujours disponibles en banque de graines et 380 lignées dérivées de la population après les 12 générations de recombinaison. Cette population a été génotypée avec la puce 9K iSelect, représentant environ 5 000 SNPs localisés sur tout le génome, additionnée de 14 marqueurs localisés dans des gènes candidats. Ce jeu de données moléculaires a été complété par des données fines de phénotypage de la précocité de floraison. Suite aux 12 générations de panmixie, le DL de cette population a été très réduit, à longue comme à moyenne distance (<10cM). Ce faible DL nous a amené à développer un algorithme basé uniquement sur le DL qui ordonne les marqueurs de manière à avoir un DL décroissant monotone avec la distance. L'algorithme ordonne globalement de la même manière que la carte génétique les marqueurs à longue distance mais à courte distance le DL est moins lié à la distance génétique. La différence réside sur l'équilibre entre les effets de la recombinaison et de la dérive génétique sur le DL. L'intérêt de la population MAGIC INRA pour détecter des QTLs a ensuite été étudié avec deux approches : une approche évolutionniste et une approche de génétique d'association. La première approche détecte les loci soumis à sélection par comparaison des fréquences alléliques de la population initiale (G0) et de la population évoluée (G12) grâce à une nouvelle méthode. La population initiale est composée des parents pondérés par une contribution estimée avec une nouvelle méthode bayésienne. 26 régions génomiques soumises à sélection ont été détectées. Une analyse de génétique d'association avec les marqueurs détectés sous sélection a montré que respectivement cinq et trois zones étaient associées à la précocité avec un semis d'automne et au caractère printemps/hiver. Une analyse phénotypique a effectivement mis en évidence la précocification de la date de floraison et une augmentation de la proportion de plantes de type printemps. Une analyse de génétique d'association a ensuite été réalisée sur les lignées SSD sur 12 caractères x environnements i.e. la date d'épiaison et le temps de remplissage du grain mesurés dans six environnements. Les tests d'association ont aussi été réalisés avec des variables synthétisant l'information présente dans plusieurs traits phénotypiques soit avec une ACP, soit avec un modèle écophysiologique. Au total, toutes ces analyses ont détecté six QTLs dont trois correspondants à des gènes majeurs. Parmi ces six QTLs, deux sont spécifiques des caractères mesurés avec un semis d'automne et deux avec ceux mesurés avec un semis de printemps. / Nowadays, with the dramatically increase of available molecular markers, there is a deep need for new populations allowing to exploit all of this information to better understand the genetic architecture of complex traits. MAGIC populations as they are built to bring together bi-parental populations and association panel advantages, provide such powerful detection and fine mapping capacities. The aim of these PhD was to study the MAGIC INRA population usefulness for the study of genetic architecture of earliness. This population is derived from 12 cycles of random crosses between 60 founders, turning wheat from selfing to outcrossing thanks to the use of a nuclear male sterility gene (ms1b, Probus donor). This population is composed of 56 parents still available and 380 SSD lines. Parents and SSD lines were genotyped using the 9K iSelect SNPs array, providing around 5 000 SNPs on the whole genome, as well as 14 addition markers located in candidate genes. They were also finely phenotyped for earliness traits. With the 12 panmictic generations, the population LD decreased strongly, especially at long and medium distance (<10cM). This allowed us to develop an algorithm mapping markers on the sole pairwise LD information, ordering markers in a way to have the LD decreasing along the distance. When considering long distances, overall the results were consistent with the order found on genetic maps while at short distance LD was poorly linked to genetic distance. These differences between long and short distances were linked to the balance between recombination and drift effects on LD. The usefulness of the MAGIC INRA population for QTL detection was analyzed with two approaches: an evolutionary approach and an association genetics approach. The first one detects loci under selection by identifying high shift in allelic frequency with a new method. The initial population was composed of founders weighted by a contribution estimated with a new Bayesian method. 26 genomic areas under selection were detected. An association genetics analysis with the markers detected as under selection showed respectively five and three genomic regions associated with earliness and growth habit. Actually the G12 population was found phenotypically earlier than the G0 and with more spring individuals. A broader association genetics analysis was performed on G12 population, studying 12 traits x environments i.e. heading date and grain filling time, both observed in six environmental conditions. Two additional integrated traits from either PCA or ecophysiological model were also analyzed. In all, these different analyses detected six QTLs, three of them corresponding to candidate genes. Among these six QTLs, two were specific to autumn sowing and two specific to spring sowing.

A genética molecular permite o entendimento dos mecanismos que regulam o desenvolvimento dos órgãos vegetais em resposta a fatores bióticos e abióticos. A regulação de vias gênicas é de fundamental importância no sucesso reprodutivo, evolutivo e econômico dos vegetais. Uma das modalidades de regulação é a pós transcricional através de microRNAs (miRNAs). Tratam-se de pequenos RNAs endógenos não codantes que possuem uma complementaridade quase perfeita em plantas. Em plantas, muitos genes-alvos de miRNA codificam-se para fatores de transcrição, como os genes SQUAMOSA Promoter-Binding Protein-Like (SPL/SBP). O microRNA156, conservado entre as Angiospermas, regula diversos fatores de transcrição da família SBP. O módulo miR156/SBP, denominado via da idade (AGE), atua ao longo do ciclo de vida dos vegetais regulando as transições de fase: juvenil-adulta e vegetativa-reprodutiva. O tomateiro, Solanum lycopersicum L., possui genes SlSBPs regulados pelo miR156 e com funcionalidade não esclarecida. Dentre aqueles, o gene SlSBP6c (Solyc12g038520) se destaca por possuir maior similaridade filogenética com SPL6s/SBP6s de solanáceas do que seus genes homólogos SlSBP6a e SlSBP6b o que sugere a hipótese de um possível ganho de função. Com o intuito de testar essa hipótese, o presente trabalho objetivou caracterizar funcionalmente o gene SlSBP6c. Para tanto, utilizou-se o genótipo 35S::rSlSBP6c, planta transformada de tomateiro cultivar Micro-Tom (MT) que super-expressa a versão resistente ao miR156 do gene SlSBP6, fusionada ao promotor viral 35S. Este material vegetal foi gerado pelo laboratório de Genética Molecular do Desenvolvimento Vegetal e cedido para execução desta pesquisa. O trabalho se desenvolveu em duas etapas: caracterização molecular e morfo-fisiológica. Primeiramente, os genes SlSBP6a, SlSBP6b e SlSBP6c de tomateiro foram analizados quanto a sua expressão ao longo do desenvolvimento em folhas e inflorescência. E, posteriormente, foram analisados a complexidade foliar, o tempo de florescimento, a transição do meristema vegetativo para o reprodutivo, o teor relativo de clorofila e a fotossíntese líquida. Os resultados obtidos demonstram que os genes SlSBP6a e SlSBP6c são semelhantes no padrão de expressão gênica na homologia das protéinas que o codificam, indicando similaridade funcional. A de-regulação do gene SlSBP6c leva ao aumento a complexidade foliar, o teor relativo de clorofila e a fotossíntese líquida. O atraso na transição do meristema vegetativo para o reprodutivo se evidencia por um florescimento tardio nas plantas que super-expressam o gene SlSBP6c. Os resultados demonstram que o gene SlSBP6c exerce funcionalidade no tomateiro atuando na transição de fase vegetativo-reprodutivo. / Molecular genetics allows the understanding of the mechanisms that regulate the development of plant organs in response to biotic and abiotic factors. The regulation of gene pathways is of fundamental importance in the reproductive, evolutionary and economic success of the plants. Research has been increasing the knowledge about post-transcriptional regulation through microRNAs (miRNAs). The miRNAs are small non-coding endogenous RNAs that have almost perfect complementarity in plants. Many miRNA target genes in plants are encoded by transcription factors, such as the SQUAMOSA PROMOTER-BINDING PROTEIN-LIKE (SPL / SBP) genes. MicroRNA156 is conserved among Angiosperms and regulates several transcription factors of the SBP family. The miR156 / SBP module, called the age pathway (AGE), acts throughout the life cycle of plants regulating phase transitions juvenile-adult and vegetative-reproductive. The tomato, Solanum lycopersicum L., has newly described and unintelligently regulated miR156 regulated SlSBPs. Among these, the gene SlSBP6c (Solyc12g038520) stands out for having greater phylogenetic similarity with solanaceous SBP6s than its homologous genes SlSBP6a and SlSBP6b, indicating a possible gain of function related to characteristics of this family of plants as fleshy fruits and composite leaves. In order to test this hypothesis the work aimed to characterize the SlSBP6c gene functionally. Using as a tool the 35S::rSlSBP6c genotype, transformed tomato plant micro-Tom (MT) that over-expresses the miR156 resistant version of the SlSBP6 gene, fused to the 35S viral promoter. The Laboratory of Molecular Genetics of Plant Development generated this plant material. The work was developed in two stages: molecular and morpho-physiological characterization. In the first the genes SlSBP6a, SlSBP6b and SlSBP6c of tomato were analyzed for their expression throughout the development in leaves and inflorescence. In the second, the leaf complexity, the flowering time, the transition from vegetative to the reproductive meristem, the relative chlorophyll content and the net photosynthesis were evaluated. The results obtained demonstrate that the SlSBP6a and SlSBP6c genes are very similar in the pattern of gene expression in the homology of the coding proteins, indicating a functional similarity. The SlSBP6c gene acts to increase leaf complexity, relative chlorophyll content and liquid photosynthesis. A late flowering in plants that overexpress the SlSBP6c gene evidences the delay in the transition from the vegetative to the reproductive meristem. The data set demonstrates that the SlSBP6c gene has important functionality in tomatoes acting on vegetative-reproductive phase transition.

In den letzten Jahren ist das Interesse der Europäer am Verbrauch „Exotischer Gemüsearten“ gewachsen wie z.B. für asiatische Auberginengenotypen, die sich in der Farbe, im Geschmack und der Form von den standardmäßigen dunklen violetten Auberginenfrüchten unterscheiden. Diese Entwicklung kann die Einführung und die Kommerzialisierung neuer asiatischer Auberginensorten in Westeuropa beeinflussen und dadurch die Vielfalt des Angebots mit diesem Gemüse in den gemäßigten Regionen erhöhen. Aus diesem Grund bestand das Ziel dieser Arbeit darin, einige asiatische Genotypen (hauptsächlich vietnamesischen Ursprung) hinsichtlich ihres Wachstums und Ertrags zu untersuchen und diese mit typischen „europäischen“ Sorten bei einer Kultivierung im Gewächshaus zu vergleichen. Außerdem sollte geprüft werden, ob die genetische Variabilität von Samenherkünften verwendet werden könnte, um Klone zu selektieren, die den Wachstumsbedingungen in den Gewächshäusern unter den Klimabedingungen in Deutschland angepasst sind. In den in vitro Experimenten ist die Reaktion von 5 Auberginengenotypen auf die Mikrovermehrung und auf die in vitro Verfahren ausgewertet worden. Zusätzlich wurden die Einflüsse von Wachstumsregulatoren, NAA und 2.4D, auf die Kallus- und Organbildung und indirekte Pflanzenregeneration in vitro untersucht, um Aussagen hinsichtlich der Nutzbarkeit von biotechnologischen Züchtungsmethoden, zu erhalten. Das in vitro Klonen wurde mit dem Ziel durchgeführt, Klone von ausgewählten 5 asiatischen Auberginengenotypen zu erhalten, um Aussagen zu ihrer vegetativen und generativen Entwicklung sowie dem Ertrag zu erhalten, und mit typischen „europäischen“ Sorten unter Gewächshausbedingungen zu vergleichen. Alle Genotypen wurden einer der hydroponischen Substratkultur im Gewächshaus kultiviert. Die Entwicklung der Genotypen in organischen und mineralischen Substrat wurde verglichen. Das organische Substrat hat zum besseren Wachstum aller Auberginengenotypen geführt. Die aus der in vitro Vermehrung erhaltenen Klone der asiatischen Auberginengenotypen entwickelten sich zu normalen Pflanzen, die einen typischen Habitus erreichten und teilweise einen Ertrag hatten, der mit dem der Kontrolle vergleichbar war. Die besten asiatischen Auberginenklone hatten ähnliche Ergebnisse wie die der Kontrolle sowohl im Stadium des Blühbeginns, als auch im Ertrag. Ein wichtiges Merkmal für die Auswahl einiger asiatischer Klone war ihre Fähigkeit frühzeitig zu blühen, vergleichbar mit den „europäischen“ Sorten. Die asiatischen Genotypen waren charakterisiert durch schmalere und leichtere Früchte mit einem guten Geschmack, weniger Samen und einer guten Konsistenz des Fruchtfleisches im Vergleich mit den „europäischen“ Sorten. Ausgehend von den Ergebnissen die in den Untersuchungen erzielt wurden, scheint es möglich, neue stabile Genotypen zu erhalten, die geeignet sind für eine Kultivierung in der „Substratkultur“ im Gewächshäusern und die ein Potenzial für den Erwerbsanbau unter europäischen Bedingungen haben. Für eine Optimierung der Wachstumsbedingungen, insbesondere das Formierungssystem, sind weitere Forschungsarbeiten erforderlich zumal diese Genotypen sehr starkwüchsig sind. Des Weiteren sollte der optimale Erntezeitpunkt und die Fruchtqualität untersucht werden. / Recently, there has been a growing interest of the Europeans in the consumption of „exotic vegetables“ like those of Asian eggplant genotypes different in colour, taste and shape from the traditional dark violet eggplant fruits. This may influence the introduction and commercialisation of Asian eggplant types in Western Europe, which will contribute to increase the biodiversity of this crop in temperate regions. Therefore, this work aimed at screening 4 Asian eggplant genotypes (mainly of Vietnamese origin) concerning their growth and yield in greenhouses in comparison to „European“ breeds. Moreover, it should be tested whether the genetic variability of seed progenies could be used to select plants adapted to the growing conditions in greenhouses under the climatic peculiarities in Germany. In in-vitro experiments the response of 5 selected eggplant genotypes to micropropagation and in-vitro manipulation has been evaluated. Further on the influence of plant growth regulators, e.g. NAA and 2,4 D, on the callus and organ formation, and indirect plant regeneration in-vitro were studied in preparation of use of biotechnological breeding methods later on. The in-vitro cloning was carried out with the aim to produce clones of 5 Asian eggplant genotypes to evaluate their vegetative and generative development, as well as the yield, in comparison with typical „European“ varieties under greenhouse conditions. All genotypes were cultivated in „substrate culture“ with drip irrigation. The influence of organic and mineral substrates on the growth and development of the eggplant genotypes was compared. The organic substrate favoured better growth of all eggplant genotypes. The in-vitro derived clones of Asian eggplant genotypes developed to normal plants that reached full maturity and some of them had a yield comparable with that of the controls, the typical „European“ varieties. The best Asian eggplant clones gave similar results as the controls in the beginning of flowering and the yield. The early flowering feature characteristic of some clones of Asian origin comparable to that of the typical „European“ varieties is very important for selection. Asian genotypes were characterized by smaller and lighter fruits having good taste, less seeds and good consistency in comparison with the „European“ varieties used as control. Derived from the results obtained in this research, it seems possible to obtain new stable genotypes for „substrate culture“ system in greenhouse with a potential for commercial production under European conditions. The optimization of growing conditions especially the pruning system needs further research for these very vigorously growing plant types. Further on studies regarding optimal harvesting time and fruit quality shall be done.