Magistrantūros studijų baigiamajame darbe pateikiami žaliosios šerytės morfogenezės indukcija in vitro tyrimų duomenys. Darbo metodai: vertintas kaliaus susidarymo dažnis (%), ūglių susidarymo dažnis (%), ūglių skaičius iš eksplanto (vnt.) bei šaknų formavimosi dažnis (%). Darbo objektas: Setaria viridis L. Darbo rezultatai. Tyrimų rezultatai atskleidė skirtingą kaliaus, ūglių bei šaknų formavimosi dažnį, dėl skirtingų egzogeninių augimo reguliatorių derinio ir jų kiekio maitinamojoje terpėje. Žaliosios šerytės dediferenciacijos indukcija intensyviau vyko terpėse, papildytose didesniu auksinų nei citokininų kiekiu. Žaliosios šerytės kaliaus formavimosi dažnis varijavo priklausomai nuo egzogeninių augimo reguliatorių derinio indukcijos terpėje. Augimo reguliatorių derinys 2,0 mg l-1 2,4-dichlorfenoksiacto rūgšties + 0,4 mg l-1 6-furfurylamino purino skatino intensyvesnę dediferenciaciją in vitro kultūroje. Antrinė diferenciacija intensyviausiai vyko maitinamojoje terpėje, papildytoje 0,4 mg l-1 α naftilacto rūgšties ir 2,0 mg l-1 N6-(2-izopentil) adenino. Daugiausiai ūglių iš eksplanto susiformavo maitinamojoje terpėje, papildytoje 0,3 mg l-1 NAR + 2,0 mg l-1 2iP. Žaliosios šerytės rizogenezės procesą in vitro skatino augimo reguliatorių deriniai 2,0 mg l-1 2,4D + 0,4 mg l-1 KIN, 0,2 mg l-1 NAR + 2,0 mg l-1 2iP ir 0,4 mg l-1 NAR + 2,0 mg l-1 BAP. / The master work presents the results of increasing of green millet induction of morphogenesis in vitro studies. Method of the work - evaluated callus formation frequency (%), shoot formation rate (%), number of shoots per explant (units) and root formation frequency (%). Object of the work - of Setaria viridis L. The results of work. The results of research showed differences in callus, shoot and root formation frequency of different exogenous growth regulator combination and quantity of nutrient medium. Setaria viridis L dedifferentiation induction intensively was in medium, supplemented by more quantity of auxin than cytokinin. Setaria viridis L callus formation frequency varied depending on the exogenous growth regulators combination of induction medium. Combination of growth regulators for 2.0 mg l-1 2,4-dichlorophenoxy acetic acid + 0.4 mg l-1 6-purine furfuryl amine stimulated more intensive dedifferentiation in vitro culture. Secondary differentiation was most intensive in nutrient medium supplemented with 0.4 mg l-1 α naphthyl acetic acid and 2.0 mg l-1 N6-(2-isopentyl) adenine. The most shoots from the explant were formed in a nutrient medium supplemented with 0.3 mg l-1 NAA + 2.0 mg l-1 2iP. Setaria viridis L the process of rhizogenesis in vitro stimulated the growth regulators combinations 2.0 mg l-1 2,4 D + 0.4 mg l-1 KIN and 0.2 mg l-1 NAA + 2.0 mg l-1 2iP and 0, 4 mg l-1 NAA + 2.0 mg l-1 BAP.

The ability of Candida albicans to change morphology plays several roles in its virulence and as a human commensal. The yeast-to-hyphae transition is tightly regulated by several sets of activating and repressing pathways. The DNA-binding proteins Rfg1p, Nrg1p and the global repressor Tup1p are part of the repressors found to regulate this morphogenesis. Knowledge of these repressors is based on extrapolations from homology to S. cerevisiae and from expression studies of mutants in inducing conditions, all of which are indirect means of determining a protein's function. We proposed a genome-wide location study of the Nrg1 and Rfg1 transcription factors to obtain direct data to identify their in vivo targets. Our results suggest different avenues for Nrg1p function and a regulation behaviour diverging from the previously suggested model: Nrg1p acts not only as a repressor but also as a transcription activator. Furthermore it regulates its target genes through binding in their coding regions instead binding to the expected regulatory elements on promoters.

In the last few decades, new centers have emerged at the edges of traditional cities and pre-World War II suburbs. As these evolve, do they converge towards the urban forms of traditional cities? This question is explored based on a study of urban areas in the Atlanta Metropolitan Region. Atlanta Downtown, Decatur and Marietta, are compared to the new centers in Buckhead, Cumberland and Perimeter. The evolution of the street network of Buckhead is examined in detail. The morphological history of a particular urban block in Buckheadâ "the Tower Place blockâ "is documented. Morphological analysis, focusing on street patterns, block shapes and sizes, property boundaries and building footprints, is complemented by Space Syntax, focusing on the structure of street networks and connectivity. It is shown that new urban centers tend to grow on very large blocks accessed through major transportation infrastructure, but situated in otherwise sparse and fragmentary street environments. As these centers grow and as the density of land use increases, a secondary private road system is created, to take advantage of development potential and provide access to major building investments. The effective fragmentation of the large blocks suggests a pattern of metric convergence towards an optimum block size. In traditional cities, however, the street network is stable over time and acts as the framework for changes in architecture and land use. In the new centers, the secondary road system serves to access particular private investments without regard to the creation of a public framework of connections. From a syntactic point of view, the new centers are spatially unintelligible, thus substantially diverging from traditional cities, even as they accommodate dense mixed use developments. The thesis points to the need of developing and using subdivision regulations and zoning classifications in order to better regulate the spatial structure of new urban centers in the future.

<p>Gene regulatory networks (GRNs) provide a systems-level orchestration of an organism’s genome encoded anatomy. As biological networks are revealed, they continue to answer many questions including knowledge of how GRNs control morphogenetic movements and how GRNs evolve. Morphogenesis is a complex orchestration of movements by cells that are specified early in development. </p><p> The activation of an upstream GRN is crucial in order to orchestrate downstream morphogenetic events. In the sea urchin, activation of the endomesoderm GRN occurs after the asymmetric 4th cleavage. Embryonic asymmetric cell divisions often are accompanied by differential segregation of fate-determinants into one of two daughter cells. That asymmetric cleavage of the sea urchin micromeres leads to a differential animal-vegetal (A/V) nuclear accumulation of cell fate determinants, β-Catenin and SoxB1. Β-Catenin protein is localized into the nuclei of micromeres and activates the endomesoderm gene regulatory network, while SoxB1 is excluded from micromeres and enters the nucleus of the macromeres, the large progeny of the unequal 4th cleavage. Although nuclear localization of β-Catenin and SoxB1 shows dependence on the asymmetric cleavage, the mechanics behind the asymmetrical division has not been demonstrated. In Chapter 3, we show that micromere formation requires the small RhoGTPase, Cdc42 by directing the apical/basal orientation of the mitotic spindle at the apical cortex. By attenuating or augmenting sea urchin Cdc42 function, micromere divisions became defective and failed to correctly localize asymmetrically distributed determinants. As a consequence, cell fates were altered and multiple A/V axes were produced resulting in a “Siamese-twinning” phenotype that occurred with increasing frequency depending on the quantitative level of perturbation. Our findings show that Cdc42 plays a pivotal role in the asymmetric division of the micromeres, endomesoderm fate-determinant segregation, and A/V axis formation.</p><p> This dissertation also characterizes, at high resolution, the repertoire of cellular movements contributing to three different morphogenetic processes of sea urchin development: the elongation of gut, the formation of the primary mouth, and the migration of the small micromeres (the presumptive primordial germ cells) in the sea urchin, Lytechinus variegatus. Descriptive studies of the cellular processes during the different morphogenetic movements allow us to begin investigating their molecular control. </p><p>In Chapter 4, we dissected the series of complex events that coordinate gut and mouth morphogenesis. Until now, it was thought that lateral rearrangement of endoderm cells by convergent extension was the main contributor to sea urchin archenteron elongation and that cell divisions were minimal during elongation. We performed cell transplantations to live image and analyze a subset of labeled endoderm cells at high-resolution in the optically clear sea urchin embryo. We found that the endomesoderm cells that initially invaginate into the sea urchin blastocoel remained contiguous throughout extension, so that, if convergent extension were present, it was not a major contributor to elongation. We also found a prevalence of cell divisions throughout archenteron elongation that increased the number of cells within the gut linearly over time; however, we showed that the proliferation did not contribute to growth, and their spindle orientations were randomized during divisions and therefore did not selectively contribute to the final gut length. When cell divisions were inhibited, we saw no difference in the ability of the cells within the gut to migrate in order to elongate. Also in Chapter 4, we describe our observations of the cell biological processes underlying primary mouth formation at the end of gastrulation. Using time-lapse microscopy, photo-convertible Kaede, and an assay of the basement membrane remodeling, we describe a sequential orchestration of events that leads to the fusion of the oral ectoderm and the foregut endoderm. Our work characterizes, at higher resolution than previously recorded, the temporal sequence and repertoire of the cellular movements contributing to the length of the sea urchin larval gut and tissue fusion with the larval primary mouth.</p><p> In Chapter 5, the migration of the small micromeres to the coelomic pouches in the sea urchin embryo provides an exceptional model for understanding the genomic regulatory control of morphogenesis. An assay using the robust homing potential of these cells reveals a “coherent feed-forward” transcriptional subcircuit composed of Pax6, Six3, Eya, and Dach1 that is responsible for the directed homing mechanism of these multipotent progenitors. The linkages of that circuit are strikingly similar to a circuit involved in retinal specification in Drosophila suggesting that systems-level tasks can be highly conserved even though the tasks drive unrelated processes in different animals.</p><p> The sea urchin gene regulatory network (GRN) describes the cell fate specification of the developing embryo; however, the GRN does not describe specific cell biological events driving the three distinct sequences of cell movements. Our ability to connect the GRN to the morphogenetic events of gastrulation, primary mouth formation, and small micromere migration will provide a framework for characterizing these remarkable sequences of cell movements in the simplest of deuterostome models at an unprecedented scale.</p> / Dissertation

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / The knowledge of plants response to grazing, with emphasis on growing and senescence processes is necessary to improve the natural grasslands usage and efficiency. Based on this, this work aimed to study morphogenic characteristics of predominant natural grasses in the central region Rio Grande do Sul State (RS), under rotational grazing based on thermal time intervals. The study was carried out at Universidade Federal de Santa Maria area, in Santa Maria/RS city, from September 2010 to March 2011, in a completely randomized experimental design, with two treatments: 375 degree day and 750 degree day grazing intervals and three repetitions. Morphogenic characteristics were measured on Andropogon lateralis Nees, Aristida laevis Nees, Axonopus affinis Chase, Paspalum notatum Fluegge and Paspalum plicatulum Michx. grass species, chosen based on functional typology. There was no significant difference between the treatments, but it was verified among species and seasons. The largest leaf appearance rates, and the the smallest leaf appearance intervals, were observed on P. notatum and A. affinis species. A. laevis e P. plicatulum showed the largest leaf lifespan and leaf elongation rate. Spring is characterized as the growing season, with highest leaf appearance and elongation values, and summer is marked by the flowering initiation, represented by internodes elongation and reduction of morphogenic characteristics. P. notatum is the grazing species with the greatest adaptative potential. / O conhecimento das respostas das plantas à desfolha, com ênfase para os processos de crescimento e senescência, é necessário a fim de melhorar o uso e eficiência das pastagens naturais. Com base nisso, o trabalho teve por objetivo estudar as características morfogênicas de gramíneas nativas predominantes na região central do Rio Grande do Sul (RS), submetidas a pastoreio rotativo com intervalos determinados por somas térmicas. O trabalho foi desenvolvido no município de Santa Maria/RS, em área da Universidade Federal de Santa Maria, de setembro de 2010 a março de 2011, em um delineamento experimental inteiramente casualizado, com dois tratamentos, intervalos de pastoreios de 375 graus-dia e de 750 grausdia, e três repetições. Foram realizadas medições de características morfogênicas nas espécies vegetais Andropogon lateralis Nees, Aristida laevis Nees, Axonopus affinis Chase, Paspalum notatum Fluegge e Paspalum plicatulum Michx. selecionadas a partir de uma tipologia funcional. Não houve diferença significativa entre os tratamentos, mas houve entre espécies e entre estações. As maiores taxas de aparecimento foliar e os menores intervalos de aparecimento de folhas são observados nas espécies P. notatum e A. affinis. A. laevis e P. plicatulum apresentam as maiores durações e taxas de elongação foliares. Primavera se caracteriza como a estação de crescimento, com valores superiores de aparecimento e elongação foliar, e verão é marcado pelo início do florescimento, representado pelo alongamento dos entrenós e redução nas características citadas acima. P. notatum é a espécie com maior potencial adaptativo ao pastejo.

Les changements de forme et les mouvements des cellules constituant les tissus relèvent de la morphogenèse épithéliale. Dans les tissus segmentés les compartiments antérieurs et postérieurs représentent des domaines morphogénétiques indépendants constitués de lignées cellulaires distinctes et séparées par des barrières biophysiques. Le laboratoire a montré que lors de la fermeture dorsale de l’embryon de drosophile, certaines cellules des segments centraux de l’ectoderme, appelées « Cellules Mixer » (CMs), sont reprogrammées pour traverser la frontière segmentale dans un phénomène qui prend le nom de « mixing ». La reprogrammation des CMs est JNK dépendante induisant l’expression de novo du gène engrailed (en). La mise au point de nouveaux outils génétiques a permis de révéler le rôle de deux familles de gènes impliqués dans les mécanismes de reprogrammation et de mixing : le gène Polycomb (Pc) et les gènes Hox. La technique de DNA-FISH, qui analyse l’interaction entre Pc et le PRE d’en, a ainsi montré que la voie JNK induit l’expression de novo d’en par dé-répression de l’activité Pc dans les CMs. De manière intéressante l’analyse approfondie des mutants Pc a dévoilé que les gènes Hox abdominal-A (abdA) et Abdominal-B (AbdB) contrôlent le domaine du mixing. Des expériences de gain et perte de fonction ont par la suite confirmé le rôle positif d’abdA et le rôle négatif d’AbdB dans le mixing. En conclusion, l’ensemble des résultats obtenus ont permis de dévoiler la présence d’un réseau génétique composé de par JNK, en, Pc et les gènes Hox contrôlant les mécanismes de reprogrammation cellulaire et de remodelage des frontières segmentales au cours du développement normal. / Tissue morphogenesis relies on patterned cell shape changes and movements taking place in specific morphogenetic domains. In segmented tissues, anterior and posterior compartments represent independent morphogenetic domains which are made of distinct lineages separated by boundaries. We previously reported on a rare event leading to the exchange of specific ‘Mixer Cells’ (MCs) between compartments of the ectoderm. During dorsal closure, MCs, which are of anterior origin, cross the boundary to integrate the adjacent posterior compartment through de novo expression of the posterior determinant Engrailed (En). This reprograming process is dependent on JNK signalling and is restricted to the central abdominal region. Here, we show that JNK signalling represses Polycomb (Pc) expression and that loss of Pc leads to an absence of MCs reprogramming. FISH-DNA coupled to immunostaining further shows that MCs fate transition is accompanied by a release of the en promoter from the repressing Pc bodies. Interestingly, our genetic data reveal that spatial control of MCs reprograming depends on the activity of the Hox genes abdominal-A (abdA) and Abdominal-B (AbdB). In their respective domains, abd-A promotes mixing while abd-B behaves as a strong repressor, thus restricting cell mixing to the central abdominal region. Together, these results provide new insights into the mechanisms of developmental reprogramming, showing that segment boundary plasticity relies on regional control of cell remodelling involving a gene regulatory network composed of JNK, en, Pc, and Hox activities.

Le syndrome d’Andersen est une maladie rare et associée à la perte de fonction du canal potassique Kir2.1. Afin d’étudier sa physiopathologie, nous avons généré et caractérisé des cellules souches pluripotentes induites (iPS) contrôle et Andersen. Nous avons ensuite différencié ces cellules iPS en cellules souches mésenchymateuse (MSC). Les cellules MSC de patients présentent une capacité de différenciation en ostéoblastes et en chondrocytes diminuée par rapport aux cellules contrôle. En effet, la production de matrice extracellulaire et l'expression des master gènes des différenciations osseuses et cartilagineuses, est réduite chez les patients. Ces travaux de thèse montrent que le canal Kir2.1 est essentiel au développement osseux. Les défauts de différentiation observés pourraient expliquer les dysmorphies associées avec le syndrome d’Andersen. / Andersen's syndrome is a rare disorder associated with a Kir2.1 potassium channel loss of fuction. To study the pathophysiology, we have generated and characterized induced Pluripotent Stem cells (iPS) from control and patient cells. We have then differentiated those iPS cells into mesenchymal stem cells (MSC). Patient's MSc have a lower osteoblastic and chondrogenic differnciation ability compared to control cells. Indeed, extracellular matrix production and master gene expression of osteoblastic and chondrogenic differenciation are reduced in patient’s cells. Alltogether, these results shown that Kir2.1 channel is required for bone developement. The differenciation defects saw in patient cells could explain the Andersen's syndrome associated dysmorphies.

Au cours de ce projet de thèse, j’ai étudié le lien fonctionnel entre la morphogénèse épithéliale et la signalisation Delta-Notch, dans le cadre de la formation du tube neural chez le poisson-zèbre. La signalisation Delta-Notch est primordiale pour le développement embryonnaire et le maintien de l’homéostasie des tissus adultes. De façon inattendue, j’ai observé suite à la perte-de-fonction de Mib une perte de la polarité apico-basale dans le neuro-épithélium de la moelle épinière embryonnaire. L’analyse plus poussée de ce phénotype m’a ensuite permis de montrer que l’activité de l’intégralité de la signalisation Notch est requise pour l’établissement de la polarité apico-basale dans le tube neural de poisson-zèbre. En effet, l’inhibition des ligands de Notch et des activateurs transcriptionnels situés en aval, Rbpja et Rbpjb, résulte en l’interruption de la polarité apico-basale. De plus, l’activation ectopique de Notch entraîne un sauvetage complet de la polarité apico-basale dans les embryons déplétés pour Mib. Finalement, le mutant Mib échoue à activer la transcription de protéines de polarité apicale Crumbs1 et Crumbs2a au cours de la formation du tube neural, ce qui suggèrerait que la signalisation Notch agit en amont des complexes de polarité. De façon surprenante, nous avons également montré que le composant de la signalisation Notch, Mib, affecte les mouvements de convergence-extension et la division cellulaire orientée, appelée C-divisions, durant la neurulation et la gastrulation à travers la signalisation PCP. Cet effet de Mib sur la PCP est indépendant de son rôle sur la signalisation Notch. Généralement, cette étude révèle un double-rôle de Mib. / In this Ph.D. project, I study the functional link between epithelial polarity and Delta-Notch signaling in the context of zebrafish neural tube morphogenesis. Notch signaling, one of the major signaling pathways and of prime importance in neurogenesis, has been widely studied for its function in cell fate specifications. Surprisingly, I found that the Notch signaling component Mindbomb (Mib) loss-of-function led to a loss of apico-basal polarity in the neuroepithelium of the embryonic spinal cord. I further explored that the activity of the entire Notch signaling pathway is actually required for the earliest steps of establishment of apico-basal polarity in the zebrafish neural tube. Indeed, inhibition of Notch ligands and downstream transcriptional activators Rbpja and Rbpjb resulted in a disruption of apico-basal polarity. Moreover, ectopic activation of Notch ensued to a complete rescue of apico-basal polarity in Mib loss of function embryos. Furthermore, Mib mutant embryos fail to upregulate the transcription of the apical polarity proteins Crumbs1 and Crumbs2a in the course of neural tube formation, suggesting that Notch signalling might act upstream of polarity complexes. Moreover, I found that Mib affects convergent-extension movements and oriented cell divisions during neurulation and gastrulation through an effect on planar cell polarity. Remarkably, this effect of Mib on PCP is independent of its role in Notch signaling. These results indicate a novel role of Mib in the regulation of PCP signaling. Altogether, this study revealed a dual role of Mib in the epithelial morphogenesis of the zebrafish neural tube.

Le phénomène de morphogenèse est le fruit de la division des cellules et de leur expansion, qui sont contrôlées de façon différentielle selon les types cellulaires et les tissus. Dans le cas des plantes, le méristème apical caulinaire (MAC) produit de façon continue les organes aériens à partir de primordia qui sont initiés suite à l’accumulation locale d’une hormone végétale, l’auxine. Pour étudier le processus de formation des organes aériens, nous utilisons l’inflorescence d’Arabidopsis thaliana, dont les fleurs sont mises en place selon un patron régulier à partir de cellules dérivées de cellules souches. Au cours de ce processus, ARF5/MP– un facteur de réponse à l’auxine se liant à l’ADN – joue un rôle central. Une fois activé, il induit l’expression des facteurs de transcription LEAFY, AINTEGUMENTA et AINTEGUMENTA-LIKE6, qui sont nécessaires pour la spécification de l’identité florale et pour la croissance proliférative. A l’échelle cellulaire, des excroissances latérales sont initiées suite à des hétérogénéités locales de croissance. Dans les cellules végétales, ces différences sont dues à des modifications de la paroi cellulaire impliquant l’auxine et ses cibles, qui induisent des variations dans la dynamique des microtubules corticaux résultant en des changements de direction de croissance. Dans une moindre mesure, l’auxine diminue la rigidité des parois cellulaires préalablement à la formation d’un nouvel organe, conduisant à des changements de taux de croissance. Ceci est corrélé à l’activation transcriptionnelle de nombreux gènes qui sont impliqués dans les modifications de la paroi. Ainsi, la voie de signalisation de l’auxine régule l’initiation des primordia en intégrant d’une part l’activation d’un réseau de régulation transcriptionnelle et, d’autre part, la rigidité et l’anisotropie de la paroi cellulaire, impactant directement le taux et la direction de croissance.Cette thèse soutient l’idée selon laquelle l’initiation des organes dans le MAC repose sur des boucles de rétroaction là où des changements locaux de propriétés de la paroi cellulaire influent sur le réseau moléculaire. Il est probable que d’autres hormones soient nécessaires afin de canaliser l’initiation des organes. / The process of morphogenesis is driven by cell division and expansion, which are controlled ina differential manner among cell types and tissues. In plants, the above ground organs arecontinuously produced by the shoot apical meristem (SAM), where the initiation of newprimordia is triggered by the local accumulation of the plant hormone auxin. We study theprocess of morphogenesis in the inflorescence of Arabidopsis thaliana, where flowers areformed in a regular pattern from the SAM.The DNA-binding auxin response factor ARF5/MP plays a central role in the initiation offlowers. After its activation, it induces the expression of LEAFY, AINTEGUMENTA andAINTEGUMENTA-LIKE6 transcription factors necessary for the specification of floralidentity and proliferative growth. However, at the cellular level, the initiation of lateraloutgrowths depends on regional differences in growth. In plant cells, these processes areregulated via modifications of the cell wall. Auxin and its downstream targets are also involvedin these processes, by activating changes in the dynamics of the cortical microtubules, whichresult in changes in growth direction. Auxin also slightly reduces wall rigidity prior to organoutgrowth in the SAM, which results in changes in growth rate. This is correlated with thetranscriptional activation of a number of cell wall modifying genes.Thus, auxin signaling regulates primordium initiation by integrating the activation of atranscriptional regulatory network and both the stiffness and anisotropy of the cell wall, whichdirectly influence the rate and direction of growth.The findings of this thesis provide evidence indicating that the mechanisms of organ initiationat the SAM involve feedbacks where changes in the local properties of the cell wall influencethe molecular regulation of the transcriptional regulatory network. Our results suggest that thismight require the influence from other hormones, different from auxin, that funnel theinitiation of lateral outgrowths.

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No. of bitstreams: 2 license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) artur_amaral_nascimento.pdf: 1903978 bytes, checksum: ba8d36a75a72310e6e7df1f98b9e4705 (MD5) Previous issue date: 2017 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior (CAPES) / Objetivou-se com este trabalho avaliar o desempenho agron?mico, por meio da produ??o e valor nutritivo, e realizar an?lise de agrupamento com base nas caracter?sticas morfog?nicas e estruturais de h?bridos de Brachiaria decumbens previamente selecionados pela EMBRAPA Gado de Corte. Foram avaliados 15 h?bridos em delineamento em blocos ao acaso com tr?s repeti??es. Para avalia??o de produ??o e valor nutritivo, foram observadas diferen?as significativas para massa seca total, massa seca da folha, massa seca do colmo, rela??o l?mina:colmo, porcentagem de colmo, porcentagem de material morto, fibra em detergente ?cido, digestibilidade in vitro da mat?ria org?nica e lignina. Para a massa seca total e massa seca de folhas, observou-se maior m?dia para o h?brido R41. Em rela??o ? massa seca de colmo e porcentagem de colmo, o menor valor encontrado foi para o h?brido S16, enquanto o R41 apresentou resultado superior. Consequentemente, o h?brido S16 obteve maior rela??o l?mina:colmo e o R41 a menor. O h?brido S16 apresentou maiores quantidades de fibra em detergente ?cido e lignina. O pior resultado para massa seca total foi registrado para h?brido R147. Tamb?m foram encontradas diferen?as para porcentagem de material morto, no qual o h?brido R128 apresentou maior m?dia. Dentre todos os h?bridos avaliados, o S16 apresentou menor massa seca de colmo, menor porcentagem de colmo e maior rela??o l?mina:colmo, por?m maiores teores de lignina e fibra em detergente ?cido e, consequentemente, menor digestibilidade in vitro da mat?ria org?nica. Aten??o especial deve ser dada ao h?brido R23, que se destacou por apresentar elevada massa de folhas e baixo teor de lignina. Para a an?lise de agrupamento, verificou-se a forma??o de 5 grupos pelas dist?ncias euclidiana quadrada e m?dia e 8 grupos pela dist?ncia de Mahalanobis. Pode-se observar que o grupo 5 reuniu maior quantidade de caracter?sticas com potencial para o melhoramento, em ambas dist?ncias avaliadas. Este grupo apresentou elevados valores para rela??o l?mina:colmo, n?mero de folhas vivas, dura??o de vida das folhas e baixa taxa de senesc?ncia foliar. Entretanto, foi registrado baixo n?mero m?dio de perfilhos. O oposto pode ser observado para o grupo 4. O grupo 1 foi composto pela maioria dos h?bridos, foi poss?vel verificar que os mesmos apresentaram caracter?sticas medianas em rela??o aos demais grupos. As caracter?sticas taxa de alongamento de colmo, n?mero de folhas vivas, dura??o de vida das folhas, n?mero m?dio de perfilhos, taxa de senesc?ncia foliar e rela??o l?mina:colmo foram as que mais contribu?ram para a distin??o dos grupos morfog?nicos. O grupo morfog?nico 5 destacou-se pelo perfil com baixo alongamento de colmos, elevado n?mero de folhas vivas, longevidade e rela??o folha colmo, com baixo n?mero de perfilhos. O grupo 3 foi caracterizado por elevado perfilhamento e rela??o l?mina colmo. Dentre todos os grupos avaliados, o grupo 4 apresentou a maior taxa de senesc?ncia foliar e a menor dura??o de vida das folhas, que permite sugerir que estas plantas podem ser avaliadas em sistemas de pastejo mais intensivo. / Disserta??o (Mestrado) ? Programa de P?s-Gradua??o em Zootecnia, Universidade Federal dos Vales do Jequitinhonha e Mucuri, 2017. / The objective of this study was to evaluate the agronomic response of Brachiaria decumbens hybrids using production and nutritive value traits and to group this plants with the cluster analysis based on morphogenic data. The hybrids were previously selected in the EMBRAPA Beef Cattle Breeding Program. Were evaluated 15 hybrids in complete randomized block design with three replicates. In the agronomic evaluation, significant effect was observed to total, leaves and stems dry mass, leaf:stem ratio, stems and dead material percentage, acid detergent fiber, in vitro organic matter digestibility and lignin. To total and leaves dry mass the higher response was observed to the hybrid R41. To stems dry mass and percentage, the lower value was observed to S16, while R41 had the higher values. In consequence, the S16 plants had a substantially high leaf:stem ratio. The lower production of total dry mass was observed to R147 hybrid. Significant differences also were observed and the R128 plants had the higher value. In the range of hybrid evaluated. Should be emphasized that S16 plants had the lowest stems mass and percentage with the highest leaf:stem ratio, but its results showed high amounts of acid detergent fiber, lignin and low in vitro organic matter digestibility. Special attention also should be given to R23 plants which had a satisfactory leaves mass production with low amounts of lignin. In the clustering analysis, was verified the formation of 5 groups with the square and average Euclidian distance and 8 groups with the Mahalanobis distance. The group 5 (S16) had more brought together more morphogenic characteristics with potential to breeding. This group had elevated values to leaf:stem ratio, number of live leaves, leaf life spam and low senescence rate. Its number of tillers was low, an undesirable characteristic. The opposite was observed to group 4 (R86). The group 1 was composed by the majority of the hybrids and showed medium characteristics in relation to the other groups. The traits stem elongation rate, number of live leaves, leaf life spam, number of tillers, senescence rate and leaf:stem ratio was the characteristics which more contributed to the differentiation of the morphogenic groups. The morphogenic group 5 had an interesting profile with low stems elongation, high number of leaves, longevity of leaves, favorable leaf:stem ratio, but low number of tillers. The group 3 was characterized by elevated number of tillers and leaf: stem ratio. Among the groups obtained, the group 4 showed the highest senescence rate and lowest longevity, which allow suggest these plants need more frequent harvests.