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Dans cette thèse, nous abordons deux problèmes de théorie des graphes liés à deux problèmes biologiques de symbiose (deux organismes vivent en symbiose s'ils ont une interaction étroite et à long terme). Le premier problème est lié au phénomène de l'Incompatibilité cytoplasmique (IC) induit par certaines bactéries parasites chez leurs hôtes. L'IC se traduit par l'impossibilité de donner naissance à une progéniture saine lorsqu'un mâle infecté s'accouple avec une femelle non infectée. En termes de graphe ce problème peut s'interpréter comme la recherche d'une couverture minimum par des "sous-graphes des chaînes" d'un graphe biparti. Un graphe des chaînes est un graphe biparti dont les noeuds peuvent être ordonnés selon leur voisinage.En terme biologique, la taille minimale représente le nombre de facteurs génétiques impliqués dans le phénomène de l'IC. Dans la première moitié de la thèse, nous abordons trois problèmes connexes à ce modèle de la théorie des graphes. Le premier est l'énumération de tous les graphes des chaînes maximaux arêtes induits d'un graphe biparti G, pour lequel nous fournissons un algorithme en delai polynomial avec un retard de O(n^2m) où n est le nombre de noeuds et m le nombre d'arêtes de G. Dans la même section, nous montrons que (n/2)! et 2^(\sqrt{m}\log m) bornent le nombre de sous-graphes de chaînes maximales de G et nous les utilisons pour établir la complexité "input-sensitive" de notre algorithme. Le deuxième problème que nous traitons est de trouver le nombre minimum de graphes des chaînes nécessaires pour couvrir tous les bords d'un graphe biparti.Pour résoudre ce problème NP-hard, en combinant notre algorithme avec la technique d'inclusion-exclusion, nous fournissons un algorithme exponentiel exact en O^*((2+c)^m), pour chaque c > 0 (par O^* on entend la notation O standard mais en omettant les facteurs polynomiaux). Le troisième problème est l'énumération de toutes les couvertures minimales par des sous-graphes des chaînes. Nous montrons qu'il est possible d'énumérer toutes les couvertures minimales de G en temps O([(M + 1) |S|] ^ [\ log ((M + 1) |S|)]) où S est le nombre de couvertures minimales de G et M le nombre maximum des sous-graphes des chaînes dans une couverture minimale. Nous présentons ensuite la relation entre le second problème et le calcul de la dimension intervallaire d'un poset biparti. Nous donnons une interprétation de nos résultats dans le contexte de la dimension d'ordre / In this thesis, we address two graph theoretical problems connected to two different biological problems both related to symbiosis (two organisms live in symbiosis if they have a close and long term interaction). The first problem is related to the size of a minimum cover by "chain subgraphs" of a bipartite graph. A chain graph is a bipartite graph whose nodes can be ordered by neighbourhood inclusion. In biological terms, the size of a minimum cover by chain subgraphs represents the number of genetic factors involved in the phenomenon of Cytoplasmic Incompatibility (CI) induced by some parasitic bacteria in their insect hosts. CI results in the impossibility to give birth to an healthy offspring when an infected male mates with an uninfected female. In the first half of the thesis we address three related problems. One is the enumeration of all the maximal edge induced chain subgraphs of a bipartite graph G, for which we provide a polynomial delay algorithm with a delay of O(n^2m) where n is the number of nodes and m the number of edges of G. Furthermore, we show that (n/2)! and 2^(\sqrt{m} \log m) bound the number of maximal chain subgraphs of G and use them to establish the input-sensitive complexity of the algorithm. The second problem we treat is finding the minimum number of chain subgraphs needed to cover all the edges of a bipartite graph. To solve this NP-hard problem, we provide an exact exponential algorithm which runs in time O^*((2+c)^m), for every c>0, by a procedure which uses our algorithm and an inclusion-exclusion technique (by O^* we denote standard big O notation but omitting polynomial factors). Notice that, since a cover by chain subgraphs is a family of subsets of edges, the existence of an algorithm whose complexity is close to 2^m is not obvious. Indeed, the basic search space would have size 2^(2^m), which corresponds to all families of subsets of edges of a graph on $m$ edges. The third problem is the enumeration of all minimal covers by chain sugbgraphs. We show that it is possible to enumerate all such minimal covers of G in time O([(M+1)|S|]^[\log((M+1)|S|)]) where S is the number of minimal covers of G and M the maximum number of chain graphs in a minimal cover. We then present the relation between the second problem and the computation of the interval order dimension of a bipartite poset. We give an interpretation of our results in the context of poset and interval poset dimension... [etc]

Thesis (LLM. (Labour Laws)) -- University of Limpopo, 2022 / This study discusses a legal analysis of incompatibility as a ground for dismissal in the South African labour law. Incompatibility refers to the inability of an employee to maintain a harmonious relationship with his or her employer, or unable to adapt to the corporate culture of the workplace. The corporate culture is associated with the values, beliefs and behaviour to determine how employees interact with each other in the workplace. Therefore, in cases where the employer contemplates dismissing an employee on the ground of incompatibility, procedural fairness and substantive fairness should be implemented in order for the employer/s to make informed decision and ensure that the dismissal of such an employee is effected in accordance with the procedural and substantive fairness couched in the Labour Relations Act 66 of 1995 („the LRA‟). Section 23 of the Constitution of the Republic of South Africa, 1996 provides broadly the right of everyone to fair labour practices. Consequently, the LRA was established to give effect to this constitutional provision. In terms of section 185 of the LRA everyone has the right not to be unfairly dismissed. Be that as it may, incompatibility is not clearly defined in section 188 of the LRA. In fact, there are no guidelines nor corrective measures implemented in the workplace to deal with incompatibility. Hence incompatibility is dealt with under dismissal based on incapacity. In most cases employers use their discretion in dismissing employees, thereby using improper procedure to end disharmony in the workplace. In summation, the central thesis of this study focuses on a legal analysis of incompatibility as a ground for dismissal in the South African labour law.

Le feu bactérien et le psylle causent d’importantes pertes économiques dans les zones de production du poirier dans le monde entier. Le développement de nouvelles variétés de poirier résistantes à ces bio-agresseurs constitue un enjeu majeur dans le cadre d’un programme de lutte intégrée. L’objectif de ce projet de thèse est l'étude du déterminisme génétique de la résistance vis-à-vis de ces deux bio-agresseurs. La thèse a été réalisée dans le cadre d’une collaboration internationale entre Fondazione Edmund Mach (Italie), Institut de Recherches en Horticulture et Semences (France) et Plant & Food Research (Nouvelle-Zélande). Une descendance interspécifique de poirier T003 x ‘Moonglow’ a été développée avec pour objectif de cumuler les résistances au feu bactérien et au psylle provenant de variétés asiatiques et européennes de Pyrus. Deux cartes génétiques ont été élaborées pour T003 et ‘Moonglow’ sur la base de marqueurs SNP (Single Nucleotide Polymorphism) et SSR (microsatellite), et la cartographie de QTLs (Quantitative Trait Loci) a permis de démontrer le déterminisme polygénique de la résistance à ces bio-agresseurs. Une sélection assistée par marqueurs (MAS) peut donc être engagée pour ces deux caractères. Des incompatibilités génétiques ont aussi été observées dans une partie de la descendance, ce qui a permis de cartographier pour la première fois chez le poirier les zones du génome liées au phénomène de « nécrose hybride ». Le développement de marqueurs liés aux gènes létaux devrait permettre aux sélectionneurs d’éviter les combinaisons incompatibles en croisement qui peuvent impacter certains caractères agronomiques co-ségrégant avec ces gènes létaux. / The goal of this PhD project was to study the genetic architecture of pear resistance to two of its most significant diseases and pests, fire blight and psylla, which cause severe yield losses in all the main pear production regions worldwide. The development of new pear varieties with resistance against these two biotic stresses is of major interest for Integrated Pest Management. This project was designed in a joint collaboration among Fondazione Edmund Mach (Italy), Institut de Recherches en Horticulture et Semences (France) and Plant & Food Research (New-Zealand). The interspecific pear F1 progeny T003 x ‘Moonglow’ was developed with the purpose of cumulating resistances to fire blight and psylla deriving from Asian and European pear cultivars. Single nucleotide polymorphism (SNP) and simple sequence repeat (SSR)-based genetic maps were built for T003 and ‘Moonglow’. Quantitative Trait Loci (QTLs) were detected for the resistances, demonstrating their polygenic nature. Marker-assisted selection (MAS) can now be applied for these two traits. Furthermore, the segregating population exhibited genetic incompatibilities, and the genomic regions associated with hybrid necrosis were mapped for the first time in pear. Development of molecular markers linked to the lethal genes should allow breeders to avoid crosses leading to incompatible combinations that could affect the expression of important agronomic traits co-segregating with these genes.

Die intrazellulären Parasiten der Bakteriengattung Wolbachia sind weit verbreitet im Phylum der Arthropoden. In vielen Wirten lösen sie eine Paarungsinkompatibilität zwischen nicht infizierten Weibchen und infizierten Männchen aus. Die mögliche Rolle dieser zytoplasmatischen Inkompatibilität in Artbildungsprozessen der Wirtsorganismen wird seit langer Zeit diskutiert. In dieser Arbeit analysieren wir häufig angeführte Kritikpunkte einer solchen Rolle mit Hilfe von mathematischen Modellen, in denen Infektionsdynamik von Wolbachia und Populationsgenetik der Wirte kombiniert werden. Die einzelnen Teile befassen sich mit dem Folgenden: (i) Wir untersuchen die Stabilität von Infektionsmustern in Wirts-Metapopulationen, indem wir kritische Migrationsraten herleiten. (ii) Zur Abschätzung des Einflusses der zytoplasmatischen Inkompatibilität auf den Genfluss zwischen Populationen berechnen wir effektive Migrationsraten. (iii) Wir bestimmen die Bedingungen, die die Verstärkung von Reproduktionsbarrieren durch die Evolution von weiblichen Paarungspräferenzen begünstigen. Schließlich (iv) wenden wir unsere Modelle auf einen realen Artbildungsprozess zweier Drosophila-Arten in Nordamerika an, diskutieren auftretende Probleme und unterbreiten Vorschläge für weiterführende Forschung. Zusammenfassend implizieren unsere Ergebnisse, dass Wolbachien häufig mit der Entstehung neuer Wirtsarten verknüpft sein können, allerdings in den meisten Fällen nur, indem sie als einer von mehreren Faktoren zur reproduktiven Isolation beitragen. Eine Verstärkung sexueller Isolation wird nur unter speziellen Bedingungen bewirkt. / The intracellular bacterial parasites of the genus Wolbachia are widespread among arthropod species. In many hosts, they induce a reproductive incompatibility between uninfected females and infected males. The potential role of this cytoplasmic incompatibility in speciation processes of the bacteria''s hosts has long been debated. In this thesis, we analyze common criticisms of such a role by means of mathematical models, combining Wolbachia infection dynamics and host population genetics. In particular, we are concerned with the following: (i) In order to measure the stability of infection patterns within host metapopulations, we derive critical migration rates. (ii) We evaluate the impact of cytoplasmic incompatibility on gene flow between populations by calculating effective migration rates. (iii) We determine the conditions that favor the evolution of female mating preferences through reinforcement. Finally, (iv) we apply our models to a particular real-world speciation process of two sibling Drosophila species in North America, discuss emerging problems, and suggest future directions of research. In summary, our results implicate that Wolbachia might be a frequent factor in host speciation, but usually only by contributing to overall reproductive isolation among other factors. Reinforcement of premating isolation is selected for only under stringent conditions.

Submitted by Maicon Juliano Schmidt (maicons) on 2015-03-21T14:19:22Z No. of bitstreams: 1 João Luiz Rocha do Nascimento.pdf: 2857036 bytes, checksum: 831e0abf6714c1b8a853becdb2bddfaf (MD5) / Made available in DSpace on 2015-03-21T14:19:22Z (GMT). No. of bitstreams: 1 João Luiz Rocha do Nascimento.pdf: 2857036 bytes, checksum: 831e0abf6714c1b8a853becdb2bddfaf (MD5) Previous issue date: 2014-09-03 / Nenhuma / Plasmado por um viés hermenêutico-filosófico, este estudo tem como objetivo demonstrar que o cumprimento do dever fundamental dos juízes de justificar suas decisões - diretamente vinculado ao direito fundamental do cidadão à obtenção de uma resposta correta - tal como estabelecido na Constituição Federal constitui uma condição de possibilidade para a extinção, no sistema processual-recursal brasileiro, dos embargos de declaração, desconstruindo o mito - fruto de uma equivocada aposta preservativa de uma dogmática jurídica refém de um sentido comum teórico e fatalista que só agrava os sintomas de baixa constitucionalidade da Norma Fundamental - de que se prestam ao aperfeiçoamento das decisões judiciais omissas, contraditórias ou obscuras quando elas não configuram ato judicial adequadamente fundamentado, sendo, por essa razão e desde a origem, nulo. A plena maximização da diretriz constitucional prevista no artigo 93, IX, a partir de uma autêntica compreensão da Constituição, esvazia qualquer razão da existência dos embargos de declaração, o que justifica a necessidade da expunção da ordem jurídica desse instituto de notória disfunção que, nos atuais contornos, encobre o autêntico sentido do ser da norma constitucional que estabelece que todas decisões judiciais devem ser fundamentadas, sob pena de nulidade. / Shaped by a philosophical hermeneutic bias, this study aims to demonstrate that compliance with the fundamental duty of judges to justify their decisions - directly linked to the fundamental right of the citizen to obtain a correct answer - as established in the Federal Constitution constitutes a condition of possibility for extinction on the Brazilian legal-appeal system, the motion for clarification, deconstructing the myth - result of a mistaken preservative bet a legal dogmatic hostage for a common theoretical and fatalistic sense that only exacerbates the symptoms of low constitutionality of the Standard Basic - that lend themselves to the improvement of missing, conflicting or unclear judgments when they do not configure properly reasoned judicial act, being, for this reason and since the origin, null. The full maximization of the constitutional directive granted under Article 93, IX, from an authentic understanding of the Constitution, flush any reason for the existence of motion to clarification, which justifies the necessity of deleting the laws of that institute notorious dysfunction which conceals, in actual contours, the true meaning of being the constitutional rule that all judicial decisions must be reasoned, under penalty of nullity.

Le système d'incompatibilité végétative a été décrit chez tous des champignons (Eumycètes) comme intervenant dans la limitation des fusions somatiques entre conspécifiques. Chez les champignons la fusion somatique est uniquement possible entre individus de même GCV (Groupe de Compatibilité Végétative). Comme tous les systèmes de reconnaissance du soi, le fonctionnement du système d'incompatibilité végétative des champignons est basé sur une grande diversité allélique. Cette thèse propose d'étudier la relation qui semble exister entre cette diversité des gènes impliqués dans l’incompatibilité végétative des champignons et la pression parasitaire exercée par des éléments cytoplasmiques délétères (ou DCE) transmis lors des fusions somatiques. Trois problématiques ont été abordées, avec trois approches différentes : (1) une approche conceptuelle générale portant sur l’évolution des systèmes de reconnaissance du soi, (2) une approche de modélisation sur le maintien de la diversité en GCV de la population de champignon par un DCE et (3) une approche expérimentale, pour étudier d’une part la perméabilité de la barrière d‘incompatibilité végétative et d’autre part l’interaction C. parasitica/CHV et les liens existant entre transmission et virulence du CHV. Ces études ont permis de montrer l'importance de la perméabilité de la barrière d'incompatibilité végétative à la fois au niveau du maintien de la diversité génétique de la population d'hôte et au niveau de la prévalence des DCE. Il semblerait donc que les DCE évoluent vers des niveaux de virulence faible du fait de la limitation de leur transmission par le système d'incompatibilité végétative de leur hôte. Nos résultats expérimentaux suggèrent que lorsque la diversité en GCV de la population d'hôte est faible, la virulence des DCE pourrait évoluer suivant le modèle du trade-off impliquant une évolution vers un niveau de virulence intermédiaire optimal. Ces travaux permettent donc de mieux comprendre les mécanismes agissant sur l'écologie et l'évolution des interactions champignon/DCE qui, au vu de cette étude, apparaissent comme de bon modèles pour l’étude des systèmes hôtes/parasites. / Vegetative incompatibility systems have been described in Fungi as controlling somatic fusion between conspecifics. For fungi, only fungi of the same vc type can fuse together. As other self recognition systems, this system involved high allelic diversity at specific genes. The issue of this work is to study the cause and effect relationship between the evolution of vegetative incompatibility systems and the selective pressure drove by cytoplasmic deleterious elements, transmitted during somatic fusion. Three problematics with three different approach were done : (1) a conceptual general framework on the evolution of self recognition systems (2) a theoretical work on the maintenance of vc type diversity by DCE and (3) an experimental work on the study of relationship between transmission and virulence in the C. parasitica/CHV host-parasite system. Ours results showed the key role of the permeability of the vegetative incompatibility barrier both for vc type diversity maintenance and on DCE prevalence. DCE would evolve toward avirulence in response to the transmission limitation by host incompatibility systems. Experimental work suggested a positive link between virulence and transmission in some population of CHV when host present a low vc type diversity, which could allow the evolution of the DCE toward an intermediate optimal virulence. This study would shed some light on mechanisms acting on the ecology and the evolution of fungi/DCE interaction which, according to our results, would be good study models for works on host-parasite systems.

We performed a retrospective study in 185 patients with myelogenous leukemias who had received hematopoietic cells from unrelated donors. The aim of this study was to answer the question wether the benefit of KIR ligand incompatibility seen in haploidentical tranplantations can also be seen using unrelated donors. We could not detect a significant difference in survival between patients with a KIR ligand incompatibility and those with either fully matched or partially mismatched unrelated donors in this patient cohort. / In der Therapie von Leukämien ist die Knochenmark- bzw. Stammzelltransplantation eine tragende Säule. Für den Transplantationserfolg ist eine Übereinstimmung der Haupthistokompatibilitätsantige (HLA-Antigene der Klassen I und II) zwischen Spender und Empfänger von zentraler Bedeutung. Diese Notwendigkeit ergibt sich aus der sogenannten MHC-Restriktion in der T-Zellrezeptorerkennung. Ob auch NK-Zellrezeptoren und deren Liganden in der Spenderauswahl berücksichtigt werden sollten, ist bisher unzureichend untersucht. Insbesondere trifft das für die KIR-Rezeptoren zu, die wie die T-Zellrezeptoren ebenfalls HLA-Antigene als Liganden besitzen. Velardi et al. haben 2002 erstmalig gezeigt, daß in der Therapie myeloischer Leukämien die Transplantation von Blutstammzellen verwandter Spender mit KIR-Liganden-Inkompatibilität von klinischem Vorteil ist. Ob KIR-Liganden-Inkompatibilität auch bei Knochenmark-/ Stammzelltransplantationen Unverwandter Bedeutung erlangen könnte, war zu Studienbeginn offen und blieb auch infolge diskrepanter Untersuchungsergebnisse von verschiedenen Arbeitsgruppen im Verlauf der Studie widersprüchlich. Im Rahmen dieser Arbeit wurde diese Fragestellung, die auch Teil einer internationalen Studie war, an 185 Spender-Empfänger-Paaren retrospektiv untersucht. Dabei wurde bei den Paaren einerseits die KIR-Liganden-Kompatibilität auf der Grundlage der HLA-C-Supertypen erschlossen (nach Velardi et al.). Andererseits konnte sie im internationalen Studienprogramm direkt aus dem KIR-Genotyp des Spenders und dem HLA-C-Supertyp des Empfängers ermittelt werden. Die Untersuchungen ergaben folgende Resultate: bei Vorliegen von KIR-Liganden-Inkompatibilität hat die Verwendung von ATG als Bestandteil der GvHD-Prophylaxe keinen Einfluß auf das klinische Ergebnis. Die Vermutungen von Giebel et al. wurden damit nicht gestützt. Die Bestimmung des KIR-Liganden-Status mit Hilfe der Rückschlußmethode allein aus dem HLA-Typ ist unzuverlässig. Für eine exakte Differenzierung ist die gleichzeitige KIR-Genotypisierung erforderlich. KIR-Liganden-Inkompatibilität ist bei unverwandten Knochenmark-/ Stammzelltransplantationen nicht von klinischem Vorteil. Auch ein gezieltes Aussuchen HLA-C-inkompatibler Spender auf der Grundlage einer KIR-Genotypisierung stellt derzeit keine therapeutische Option dar.

Flowering plants display remarkable phenotypic diversity, especially in reproductive structures, much of which is thought to be associated with pollination by animals. Pollination syndromes are collections of floral traits (e.g. flower colour, shape, odour) that are associated with a plant attracting particular functional groups of animal pollinators. We explored the extent to which traits associated with the moth pollination syndrome translated into pollination by moths in the Pacific coast dune endemic Abronia umbellata and found mixed results: in one year of study, there was no difference in seed set by day- vs. night-pollinated inflorescences, but in another year of study, night-pollinated inflorescences set significantly more seed than those pollinated during the day. We integrate this work with tests of pollen and resource limitation of seed production and with seed set surveys of natural populations to address proximate and ultimate causes of low seed set, finding low rates of pollinator visitation, high pollen limitation of seed production in all populations studied, and no evidence of endogenous resource limitation of seed production. We propose that “excess” flowers may be functionally male, serving to increase outcross siring success. The transition from self-incompatibility and obligate outcrossing to self-compatibility and predominant selfing is the most common evolutionary transition among the flowering plants and traits associated with outcrossing may become reduced across such shifts, potentially through the action of natural selection, especially if pollinators are also herbivores, or if the signals that pollinators use to locate flowers are also used by herbivores. We examined the reduction of attractive visual and olfactory floral traits in A. umbellata across a shift from outcrossing to selfing and found a reduction of all floral traits considered. We found that floral volatile emissions were reduced more strongly than flower size or floral display (number of flowers per inflorescence), but there was no evidence of an ecological cost associated with conspicuousness: we did not find reduced leaf herbivory among selfers relative to outcrossers. / Thesis (Master, Biology) -- Queen's University, 2012-08-30 19:46:23.663

Made available in DSpace on 2016-12-06T17:42:05Z (GMT). No. of bitstreams: 1 PGPV14DA009.pdf: 2537608 bytes, checksum: 52becf46e22999496c3c26525a0865d0 (MD5) Previous issue date: 2014-10-07 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / The culture of pear (Pyrus communis L.), has great potential for expansion in Southern Brazil due to climate and soil conditions. The lack of information regarding the (s) best (s) combination (s) of european pear cultivars scion and quince rootstocks as vegetative aspect and productive potential has limited the cultivation of pear in the country. In this contexto, the objetive was to evaluate the agronomic aspects of vegetative and productive cultivars scioneuropean pear (Pyrus communis. L) grafted on quince rootstocks (Cydonia oblonga. L) in médium systems, super and high planting densities, at conditions the conditions of the Santa Catarina plateau. The experiments were conducted in the área of company experimental Agrícola Fraiburgo S/A, located in Urupema, state of Santa catarina, during the cropping cycles 2011/12, 12/23 and 13/14. In Chapter I, we used three systems, characterized as average (2500 plants ha¯¹), high (5000 plants ha¯¹) and super (7500 plants ha¯¹) densities. In médium density system, the combinations evaluated among european pear cultivars and quince rootstocks were: Abbè Fetel/Adams Conference/Adams, Clapp s Favourite/EMA, Santa Maria/Adams, rocha/Adams, Packham s Triumph/Adams, Decana du Comice/Adams e Packam s Triumph/EMA. In high density planting combinations were evaluated: Conference/EMC, Clapp s Favourite/EMA, Rocha/EMC, Abbè Fetel/EMC, William s/EMC e Packham s/EMA. In the super density, evaluated the combinations: Rocha/Adams, Santa Maria/Adams, Packam s Triumph/EMC, Abbè Fetel/EMC, Abbè Fetel/Adams and Rocha/EMC. In Chapter II, we evaluated the compartibility of grafting, which consisted in the analysis of growth and vascular grafting connection in the following combinations: Abbè Fetel/Adams, Decana du Comice/Adams, Clapp s Favourite/EMA, Rocha/Adams, Packham s Triumph/EMA and Santa Maria/Adams density of 2500 plants ha¯¹ and Rocha/EMC, Abbè Fetel/EMC and William s/EMC density of 5000 plants ha¯¹. In chapter III, we evaluated the distribution of the root system of diferente combinations of european pear cultivars scion and quince rootstocks at planting density of 2500 plants ha¯¹ with the following combinations: Abbè Fetel/Adams, Clapp s Favourite/EMA, Santa Maria/Adams, Rocha/Adams, Decana du Comice/Adams and Packham s Triumph/EMA and density of 5000 plants ha¯¹: Conference/EMC, Clapp s Favourite/EMA, Rocha/EMC, Abbè Fetel/EMC, William s/EMC e Packham s Triumph/EMA. The combination Abbè Fetel/Adams is more vigorou, reporting low yield in médium super system and planting density. The combination Santa Maria grafted on quince Adams gives intermediate vegetative growth of plants and high producrtivity in médium system and super planting density. Combinations Clapp s Favourite/EMA and William s/EMC are incompatible with quince rootstocks of tested, it is possible to observe a clear discontinuity in the region of vascular graft union. Santa Maria and Rocha grafted on quince Adams exhibit a continous vascular union between cultivar and rootstock, with no symptoms of vascular disruption at any level. In planting density of 2500 plants ha¯¹, to jointly analyse the six combinations of european pear cultivars and quince rootstocks throught the spatial distribution of root length at depth, there was a higher concentration of roots in the first 40 cm of depth. Regarding the effective depth, it was observed that up to 40 cm depth concentrate 80% of the total root for all combinations of the average and six combinations evaluated, 83% of root geowth is located on the respective depth. Regarding the effective distance, it was observed that the distance at which are 80% of total root length was 80 cm for all combinations exceptd the Clapp s FAvourite/EMA, which the effective distance was 100 cm. Irt was observed that the average of the six combinations,86% of root growth in horizontal distance located up to 80 cm. Already at a density of 5000 plants ha¯¹ jointly analyzing the six combinations of euroepean pears cultivars and rootstocks quince, it was observed that the greatest concentration of the first roots 40 cm deep, about 90% of the distribution root. Regarding combinations evaluated, it was observed that cv. Packham s Triumph grafted on quince EMA provided greater root growth, and may infer that their combination, compared to the other, exploring a greater volume of soil in the planting density of 5000 plants ha¯¹ and is able to check out the shoot of plant vigor. Regarding the effective depth, it was observed that up to 30 cm deep focus 80% of total root length, evaluated for all combinations except the comnbination William s/EMC that got in this depth, only 60% of root volume. For this combination in particular, has been considered effective depth of 40 cm. As the density of 2500 plants ha¯¹ at a density of 5000 ha¯¹ plants, the major root length also concentrated in the largest amount of available nutrientes and water to the roots region, which should ensure a greater capacity of the plant cultivation of the soil, and thus greater absorption of water nutrients / A cultura da pereira (Pyrus communis. L), possui potencial de expansão em algumas regiões do sul do Brasil, devido às condições climáticas e de solo. A despeito disso, a carência de informações a respeito da(s) melhor(es) combinação(ões) entre cultivares copa de pereiras europeias e portaenxertos de marmeleiro quanto ao aspecto vegetativo e ao potencial produtivo tem limitado a produção de pera no país. Neste contexto, o objetivo do trabalho foi avaliar agronomicamente os aspectos vegetativos e produtivos de cultivares copa de pereiras europeias (Pyrus communis. L) enxertadas sobre portaenxertos de marmeleiro (Cydonia oblonga. L) em sistemas de média, alta e super densidades de plantio, nas condições edafoclimáticas da região do planalto catarinense. Os experimentos foram conduzidos na área experimental da empresa Agrícola Fraiburgo S/A, localizada na cidade de Urupema, estado de Santa Catarina, durante os ciclos de cultivo 2011/12, 12/13 e 13/14. No capítulo I, utilizou-se três sistemas, caracterizados como média (2500 plantas ha-1), alta (5000 plantas ha-1) e super (7500 plantas ha-1) densidades de plantio. No sistema de média densidade, as combinações avaliadas entre cultivares de pereiras europeias e portaenxertos de marmeleiro foram: Abbè Fetel/Adams, Conference/Adams, Clapp´s Favourite/EMA, Santa Maria/Adams, Rocha/Adams, Packham´s Triumph/Adams, Decana du Comice/Adams e Packham´s Triumph/EMA. Na alta densidade de plantio, foram avaliadas as combinações: Conference/EMC, Clapp´s Favourite/EMA, Rocha/EMC, Abbè Fetel/EMC, William´s/EMC e Packham´s Triumph/EMA. Já na super densidade, avaliaram-se as combinações: Rocha/Adams, Santa Maria/Adams, Packham´s Triumph/EMC, Abbè Fetel/EMC, Abbè Fetel/Adams e Rocha/EMC. No capítulo II, avaliou-se a compatibilidade de enxertia, que consistiu na análise de crescimento e conexão vascular no ponto de enxertia das seguintes combinações: Abbè Fetel/Adams, Decana du Comice/Adams, Clapp´s Favourite/EMA, Rocha/Adams, Packham´s Triumph/EMA e Santa Maria/Adams na densidade de 2500 plantas ha-1 e Rocha/EMC, Abbè Fetel/EMC e William´s/EMC para a densidade de 5000 plantas ha-1. No capítulo III, avaliou-se a distribuição do sistema radicular das diferentes combinações de cultivares copa de pereiras europeias e portaenxertos de marmeleiro. Na densidade de plantio de 2500 plantas ha-1, utilizou-se as seguintes combinações: Abbè Fetel/Adams, Clapp´s Favourite/EMA, Santa Maria/Adams, Rocha/Adams, Decana du Comice/Adams e Packham´s Triumph/EMA enquanto que na densidade de 5000 plantas ha-1: Conference/EMC, Clapp´s Favourite/EMA, Rocha/EMC, Abbè Fetel/EMC, William´s/EMC e Packham´s Triumph/EMA. A combinação Abbè Fetel/Adams é mais vigorosa, reportando baixo rendimento em sistema de média e super densidade de plantio. A combinação Santa Maria enxertada sobre o marmeleiro Adams, confere crescimento vegetativo intermediário às plantas e alta produtividade em sistema de média e super densidade de plantio. As combinações Clapp´s Favourite/EMA e William´s/EMC são incompatíveis com os portaenxertos de marmeleiros testados, sendo possível observar uma clara descontinuidade vascular na região de união do enxerto. Santa Maria e Rocha enxertadas sobre o marmeleiro Adams, apresentam uma união vascular contínua entre cultivar e portaenxerto, não havendo sintomas de descontinuidade vascular em nenhum nível. Para a densidade de plantio de 2500 plantas ha-1, observou-se maior concentração de raízes nos primeiros 40 cm de profundidade. Em relação à profundidade efetiva, observou-se que até 40 cm de profundidade concentram-se 80% do comprimento total de raízes para todas as combinações e que na média das seis combinações avaliadas, 83% da concentração radicular localiza-se na respectiva profundidade. Em relação à distância efetiva, observou-se que a distância na qual se encontram 80% do comprimento total de raízes foi 80 cm para todas as combinações, com exceção da Clapp´s Favourite/EMA, a qual a distância efetiva foi 100 cm. Foi possível observar que na média das seis combinações, 86% da concentração radicular na distância horizontal localiza-se até 80 cm. Já na densidade de 5000 plantas ha-1, analisando conjuntamente as seis combinações de cultivares de pereiras europeias e portaenxertos de marmeleiro, observou-se que há maior concentração de raízes nos primeiros 40 cm de profundidade, cerca de 90 % de toda a distribuição do sistema radicular. Em relação às combinações avaliadas, observou-se que a cv. Packham´s Triumph enxertada sobre o marmeleiro EMA proporcionou maior crescimento de raízes, podendo inferir que a respectiva combinação, comparada às demais, explora um maior volume de solo na densidade de plantio de 5000 plantas ha-1. Em relação à profundidade efetiva, observou-se que até 30 cm de profundidade se concentram 80 % do comprimento total de raízes, para todas as combinações avaliadas, com exceção da combinação William´s/EMC que obteve na respectiva profundidade, apenas 60% de volume radicular. Para esta combinação, a profundidade considerada efetiva foi de 40 cm. Assim como na densidade de 2500 plantas ha-1, na densidade de 5000 plantas ha-1, o maior comprimento radicular também concentrou-se na região de maior quantidade de água e nutrientes disponíveis às raízes, o que deve assegurar à planta maior capacidade de exploração do solo e, por conseguinte, maior absorção de água e nutrientes