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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
161

Mapeamento de genes associados à resistência da soja a ferrugem asiática (Phakopsora pachyrhizi) / Mapping of genes associated to Asian soybean rust (Phakopsora pachyrhizi)

Carlos Eduardo de Araujo Batista 18 June 2008 (has links)
O custo ferrugem que engloba gastos com fungicidas, os custos operacionais das aplicações, perdas de produção, e redução na arrecadação de impostos representa um elevado valor para sojicultura mundial. Assim, a ferrugem asiática da soja apresenta-se como um dos grandes desafios para a pesquisa agrícola nos próximos anos, pois o controle químico da doença é alternativa obrigatória enquanto não se dispõe de cultivares resistentes. Porém a prática representa aumento considerável no custo de produção. No Brasil estima-se que este custo, para duas aplicações gire, em torno de US$ 40,00.ha-1, sem contar os gastos operacionais com máquinas e combustível, ou seja, gasto apenas o fungicida. Considerando o exposto, este trabalho tem como objetivo avaliar duas fontes de resistência à ferrugem asiática da soja (PI 200487 e PI 459025A), e verificar se os genes responsáveis pela reação ao patógeno já foram descritos na literatura, ou seja, identificar seus respectivos grupos de ligação. A estratégia de segregantes agrupados (Bulked segregant analysis) foi utilizada para mapear os genes de interesse. Os resultados obtidos permitiram chegar as seguintes conclusões: a) a técnica BSA foi eficiente para detectar locos relacionados com a resistência à ferrugem asiática da soja; b) a PI 459025 (Bing Nam) apresenta o gene de resistência Rpp4 localizado no grupo de ligação G e c) A PI 200487 (Kinoshita) apresenta um gene diferente daqueles descritos na literatura, sendo este localizado no grupo de ligação N. Este gene pode ser denominado de Rpp5. / The costs due to Asian soybean rust, which consists of fungicides, operational application costs and reduction in paid taxes, represent severe losses for worldwide soybean production. Thus, Asian soybean rust represents one of the most challenging problems for agricultural research in the future, since chemical control of the disease is the obligated alternative while resistant cultivars are unavailable. However, fungicide application significantly increases production costs. In Brazil, it is estimated that the costs of two applications are of approximately US$ 40,00.ha-1, aside the operational costs incurred due to machinery and fuel, that is, the figure represents solely fungicide costs. Taking into account the previous considerations, the present work aims to evaluate two sources of resistance to Asian soybean rust (PI 200487 and PI 459025A), and to verify if the genes involved in pathogen-responses have already been described in previous work, by identifying their respective linkage groups. Bulked segregant analysis was used to map the genes of interest. The results allowed the following conclusions: a) BSA was effective to detect loci associated to Asian soybean rust resistance; b) PI 459025A (Bing Nam) carries the resistance gene Rpp4 mapped to the linkage group G and c) PI 200487 (Kinoshita) has a novel resistance gene mapped to the linkage group N. The identified gene is denominated Rpp5.
162

Prédiction de la qualité des bois de chêne pour l’élevage des vins et des alcools : comparaison des approches physicochimiques, sensorielles et moléculaires

Guichoux, Erwan 06 April 2011 (has links)
Au cours du vieillissement, les caractéristiques organoleptiques du vin se modifient au contact du bois de chêne. Le composé aromatique le plus important, la whisky-lactone, aux notes noix de coco et boisé, est facilement détectable et apprécié par les consommateurs.Quercus petraea et Q. robur, les deux principales espèces européennes de chêne utilisées pour le vieillissement des vins, ont des profils aromatiques très contrastés, particulièrement pour la whisky-lactone. Parvenir à identifier l’espèce de chêne permettrait de fournir aux tonnelleries des lots de bois plus homogènes. L’objectif de cette étude est d’identifier l’espèce de chêne à partir de bois sec, à l’aide de marqueurs moléculaires utilisables dans un contexte industriel. Le bois sec est un tissu mort dans lequel l’ADN est très dégradé et donc difficilement accessible. Pour optimiser l’extraction d’ADN à partir de ce tissu, nous avons développé une méthode de PCR en temps-réel ciblant l’ADN chloroplastique, permettant ainsi d’évaluer l’efficacité des différents protocoles d’extraction. Nous avons également développé des marqueurs moléculaires (SSRs et SNPs) fortement différenciés entre espèces et particulièrement bien adaptés au bois. Grâce à des protocoles d’extraction d’ADN optimisés et ces marqueurs performants, nous avons pu identifier l’espèce sur des lots de bois séchés pendant deux ans. De plus, par l’étude de 262 SNPs dont la moitié est fortement différenciée entre espèces, nous avons démontré que les gènes sélectionnés (loci « outlier ») sont très performants pour délimiter ces deux espèces proches. Ils permettent également de détecter des processus démographiques fins (flux de gènes intra- et interspécifiques), alors que les gènes a priori non-sélectionnés (loci neutres) se révèlent peu informatifs. / Most of aromatic compounds in wine are directly induced during maturation by the contactwith oak wood. For example, whisky-lactone, the most important aromatic compound,which gives a coconut and woody taste, is easily detected and appreciated by consumers.Quercus petraea and Q. robur, the two major European oak species used for wine maturation,have very contrasted aromatic patterns, especially for whisky-lactone. Identifying the speciesused for cooperage will facilitate the maturation process, for instance by providing winerieswith more homogenous batches of barrels. The objective of our study is to characterize theoak species directly from dry wood, using molecular markers that will be applicable in anindustrial context. Unfortunately, dry wood is a dead tissue in which DNA is highlydegraded and difficult to access. To optimize DNA recovery from dry wood, we developed aquantitative PCR protocol based on chloroplast DNA to evaluate the efficiency of DNAisolation protocols. We identified and developed molecular markers (SSRs and SNPs)adapted to dry wood that are particularly diagnostic. Using an optimized DNA isolationprotocol and these powerful markers, the species identity from wood samples dried duringtwo years could be successfully characterized. Using 262 SNPs highly differentiated betweenthe two species, we also demonstrate that genes under selection (outlier loci) haveoutstanding power to delimitate the two oak species and provide unique insights on intraandinterspecific gene flow, whereas genes lacking such a signature (putatively neutral loci)provide little or no resolution.
163

Organización de la diversidad genética de los cítricos

García Lor, Andrés 29 July 2013 (has links)
Citrus es el género de la subfamilia Aurantioideae de mayor importancia económica. Su origen es la región sureste de Asia, en un área que incluye China, India y la península de Indochina y los archipiélagos de los alrededores. Aunque se han realizado múltiples estudios, la taxonomía del género Citrus aun no está bien definida, debido al alto nivel de diversidad morfológica encontrado en este grupo, la compatibilidad sexual entre sus especies y la apomixis de muchos genotipos. En la presente tesis doctoral se ha estudiado una amplia diversidad del género Citrus, especies relacionadas y otros taxones de la subfamilia Aurantioideae, para poder aclarar su organización y filogenia mediante el empleo de diferentes tipos de marcadores moleculares y métodos de genotipado. Más concretamente, el germoplasma de mandarino juega un papel muy importante en la mejora de variedades y patrones, pero su organización genética no está bien definida. Por lo tanto, se ha realizado un análisis en profundidad de su diversidad y organización genética. El desarrollo de marcadores moleculares de Inserción-Deleción (indel), por primera vez en cítricos, ha permitido demostrar su utilidad para estudios de diversidad y filogenia en el género Citrus. En combinación con los marcadores de tipo microsatélite (SSR), se ha cuantificado la contribución de los tres principales taxones de cítricos (C. reticulata, C. maxima and C. medica) a los genomas de las especies secundarias y cultivares modernos. También se ha definido su estructura genética a partir de los datos obtenidos en la secuenciación de 27 fragmentos de genes nucleares relacionados con la biosíntesis de compuestos que determinan la calidad de los cítricos y genes relacionados con la respuesta de la planta a estreses abióticos. El análisis de la filogenia nuclear ha permitido determinar la relación existente entre la especie C. reticulata y Fortunella, que se diferencian claramente del grupo formado por las otras dos principales especies de cítricos (C. maxima y C. medica). Este resultado está en concordancia con el origen geográfico de las especies estudiadas. A partir de este estudio, se han desarrollado marcadores moleculares de tipo SNP con un alto valor filogenético, que han sido transferidos a géneros relacionados de los cítricos. Estos marcadores han dado un resultado muy positivo en el género Citrus y serán de gran utilidad para el establecimiento de la huella genética del germoplasma en un nivel de diversidad más amplio. Se ha estudiado la organización genética dentro del germoplasma mandarino (198 genotipos de tipo mandarino pertenecientes a dos colecciones, INRA-CIRAD e IVIA), así como la introgresión de otros genomas mediante el uso de 50 y 24 marcadores de tipo SSR y indel, respectivamente, además de cuatro marcadores InDel mitocondrial (ADNmt). Se ha observado que muchos genotipos, que se creía que eran mandarinos puros, presentan introgresión de otros genomas ancestrales. Dentro del germoplasma de mandarino, se han identificado a nivel nuclear cinco grupos parentales, a partir de los cuales se originaron muchos genotipos, dando lugar a estructuras hibridas complejas. Se ha observado incluso, genotipos con un origen maternal no mandarino, determinado por los marcadores de ADNmt. La presente tesis doctoral ha aportado nueva información sobre las relaciones filogenéticas entre las especies del género Citrus, géneros cercanos, así como de las especies secundarias. Además, se han desarrollado nuevos marcadores moleculares que se complementan entre sí. Se ha establecido una nueva organización genética del germoplasma mandarino y se han caracterizado adecuadamente las dos colecciones de cítricos en estudio. Por lo tanto, todas estas contribuciones, ayudarán a los programas de mejora para la obtención de nuevas variedades de cítricos de alta calidad y permitirán optimizar la conservación y uso de los recursos genéticos existentes, así como su caracterización genética y fenotípica. / García Lor, A. (2013). Organización de la diversidad genética de los cítricos [Tesis doctoral no publicada]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/31518 / TESIS
164

Genetic analysis of traditional Ethiopian Highland Maize (Zea Mays L.) using molecular markers and morphological traits : implication for breeding and conservation

Beyene, Yoseph Aydagn 21 February 2006 (has links)
Knowledge of the genetic variation of crop collections is essential for their efficient use in plant breeding programs. The Ethiopian Highland Maize Germplasm Collection Mission was launched throughout the highlands of Ethiopia in 1998 and 287 traditional maize accessions were collected from farmers’ fields. To date, no information was available on the morphological and genetic diversity in this important collection. Various molecular marker techniques and quantitative genetics approaches were applied to accurately unravel the extent of phenotypic and genetic diversity, to study patterns of morphological and molecular variation and to determine association of molecular markers with quantitative trait variation, with the view of designing a sound breeding program and management strategy for maize in the highlands of Ethiopia. The morphological study confirmed that traditional Ethiopian highland maize accessions contain large amounts of variation for agro-morphological traits. The broad trait diversity observed among the accessions suggested ample opportunities for the genetic improvement of the crop through selection directly from the accessions and/ or the development of inbred lines for a future hybrid program. Selection practices followed by local farmers are mostly consistent within agroecology and gave rise to morphologically distinct maize accessions in different agroecologies. This underscores the importance of considering farmers’ knowledge of diversity in the collection and evaluation of local accessions. The results of amplified fragment length polymorphism (AFLP) and microsatellite or simple sequence repeat (SSR) marker analyses showed that bulking leaf samples from 15 individual plants per out-bred accession is an effective means of producing representative profiles of individual plants, thereby reducing the cost of DNA extraction and subsequent marker analysis of open-pollinated varieties. Cluster analyses based on AFLP and SSR data showed that most of the accessions collected from the Northern agroecology were genetically distinct from the Western and Southern accessions suggesting that differentiation for adaptive traits for drought conditions may have occurred in the Northern accessions. However, there was very little genetic differentiation between the Western and Southern accessions suggesting gene flow between the two agroecologies and recent introduction of similar improved varieties in these agroecoogies . In both marker systems, high mean genetic diversity was observed among the traditional Ethiopian highland maize accessions. This is possibly due to (i) the continuous introduction of maize from abroad by different organizations; (ii) genetic variation generated through farmers management practices; and (iii) the presence of different environmental conditions in the highlands of Ethiopia to which local landraces may have been adapted. The correlation between the morphological dissimilarity matrix and the matrices of genetic dissimilarity based on SSR and AFLP markers were 0.43 and 0.39, respectively (p = 0.001 in both cases). The correlation between SSR and AFLP dissimilarity matrices was 0.67 (p = 0.001). These significant correlations indicate that the three independent sets of data likely reflect the same pattern of genetic diversity, and validate the use of the data to calculate the different diversity statistics for Ethiopian highland maize accessions. From this study, three groups of maize accessions with distinctive genetic profiles and morphological traits were identified that will be useful for future collection, conservation and breeding programs of maize for the highlands of Ethiopia. A pilot association study using SSR markers and quantitative trait variation indicated that molecular markers could be useful to identify genetic factors controlling earliness, tallness, grain yield and associated traits, which could be exploited by various breeding schemes. The analytical tools outlined in this dissertation can be a useful tool in managing genetic variation of open-pollinated crops and will aid in the conservation of unique genetic diversity. Production stability and global food security are linked to the conservation and exploitation of worldwide genetic resources and this research attempts to add to that body of knowledge. Copyright 2005, University of Pretoria. All rights reserved. The copyright in this work vests in the University of Pretoria. No part of this work may be reproduced or transmitted in any form or by any means, without the prior written permission of the University of Pretoria. Please cite as follows: Beyene, YA 2005, Genetic analysis of traditional Ethiopian Highland Maize (Zea Mays l.) using molecular markers and morphological traits : implication for breeding and conservation, PhD thesis, University of Pretoria, Pretoria, viewed yymmdd < http://upetd.up.ac.za/thesis/available/etd-02212006-112610 / > / Thesis (PhD (Genetics))--University of Pretoria, 2005. / Genetics / unrestricted
165

Genetic analysis of Helosciadium repens (Jacq.) W.D.J.Koch populations in Germany - Fundamental research for conservation management

Herden, Tobias 03 February 2020 (has links)
Crop wild relatives (CWR) are an indispensable and at the same time threatened genetic resources for plant breeding. The study uses wild species related to celery to demonstrate how genetic resources of CWRs can be actively maintained in their natural surroundings (in-situ). Genetic reserves should be designated for long term conservation of selected occurrences. The study presents the selection procedure in detail, aiming at the identification of occurrences and sites suitable for the designation of genetic reserves, the spatial model of a genetic reserve and first practical results of the project. The overall aim of the project is the establishment of a nationwide network of genetic reserves for Apium graveolens, Helosciadium repens, H. nodiflorum and H. inundatum, the four wild celery species native to Germany. Helosciadum repens (Jacq.) W.D.J.Koch is threatened by genetic erosion due to a decline in population numbers and sizes. The loss of any population is an irretrievable loss of diversity and opportunity to enhance crops in the future. Genetic reserves are one way to conserve these populations and their genetic potential. Twenty-seven populations were selected for the analysis in a decision process based on site information. Microsatellites (SSR) were used to elucidate the genetic diversity of German populations. A cluster analysis was performed to see if the individuals form clusters of similarity. For that, a discriminate analysis of principal components (DAPC) was conducted, as the inbreeding index indicated a high number of inbreeding events in the populations and thus discordance with HWE (Hardy-Weinberg equilibrium). The analysis identified six genetic groups, which coincide well with the geographic origin of the analysed plants. The allelic richness (mean counts of alleles per individual per population) was higher in the southern populations compared to the northern ones. This North-South discrepancy was also visible as a high heterogeneity in the cluster assignments in the DAPC analysis. These differences in genetic diversity might be a result of the biogeographic history of Europe, especially the last glacial maximum. For the establishment of genetic reserves, two populations were considered as most important: The population that differs the most from the average genetic composition and the population that represents the average genetic composition of a population the best. The two extremes of differentiation were interpreted as such that the former has a specific adaptation to its local environment, and the latter represents all populations the best. DifferInt was used to analyse the SSR data and validate the differentiation of all populations compared to a pool of populations. However, SSRs are not capable of detecting adaptive traits. Populations were additionally chosen from different eco-geographic units (EGU), to increase the chance of capturing different traits. EGUs (Naturräume) are areas of specific abiotic and biotic features. These features may influence selection pressures and induce local adaptations. Based on site parameters and genetic data, 14 most appropriate wild populations (MAWP) were identified for genetic reserves establishment. For H. repens, two eco-forms are known and described in the literature. Besides their different habitats (terrestrial/semi-terrestrial and aquatic) they can be differentiated by morphological traits. Leave and stolon sizes and flowering behaviour differ significantly. Furthermore, the roots of the aquatic forms do not anchor in soil but on other aquatic plants, wood or roots of trees, while the terrestrial form exhibits a shallow root system network similar to other perennial species. To this end, no genetic analysis was conducted to clarify the phylogenetic status of the putative forms and authors avoided the usage of any specific noun rather than form. The SSR data from the previous study was evaluated, particularly with regards to the two forms. Additionally, an ISSR analysis was conducted, and the data was used to perform a PCA. There was no genetic clustering regarding the two forms neither in the SSR nor in the ISSR data. Nonetheless, the North-South discrepancy in the genetic diversity that was visible in the DAPC plot was confirmed in the PCA of the ISSR data. However, markers may fail to detect quantitative variation for adaptively important traits. As the most obvious difference in the two habitats was the water availability, the adaptation of both forms to drought stress was studied by measuring the relative water content of leaves, system water content and water loss during drought stress conditions. The stomatal index was measured for different water treatment levels. The results indicate that phenotypic plasticity rather than genotypic adaptation is responsible for different H. repens phenotypes.
166

Security Sector Change in Georgia, 1985 - 2008 Local Dynamics, Politics of Reform and Paramilitaries

Koyama, Shukuko January 2018 (has links)
The literature on security sector actors in transitional societies emerging from war and/or authoritarianism has evolved by critiquing local perspectives recently. While the existing literature has extensively analysed transitional societies in Africa, Middle East and Eastern Europe, the thesis adds a new geographical perspective by providing a case study of security sector change processes in the Republic of Georgia, 1985 - 2008. More specifically, the thesis examines the local processes and drivers of security sector change in Georgia, and their interrelationships with donor supported programmes including SSR. The thesis employs a political economy analysis to examine indigenous security sector actors and their characteristics. Based on the approach, the thesis particularly examines processes of change and reform of policing institutions. The paramilitary is identified and examined as a key focus for analysis. The research shows that political dynamics among a few political elites determined the course of security sector change in Georgia. Despite ample external assistance, domestic political dynamics remained the main driving factor in the SSR agenda-setting process. In the politically-driven security sector change efforts, the restoration and maintenance of regime security remained a priority under both the Shevardnadze and Saakashvili regimes. Overall, the security sector actors played significant role in the political developments. Consequently, the process of changing these actors was a largely domestically driven political process. The role of paramilitaries in relation to regime security and the security sector change agenda-setting process in Georgia requires the security sector research to treat paramilitary as a distinguished unit for consideration. / Akino Yutaka Eurasia Fund and the United Nations University Akino Memorial Research Fellowship.
167

Caracterização agronômica e molecular da coleção nuclear de arroz da Embrapa / Agronomic and molecular characterization of Embrapa Rice Core Collection

BUENO, Luíce Gomes 31 August 2010 (has links)
Made available in DSpace on 2014-07-29T14:52:04Z (GMT). No. of bitstreams: 1 TESE LUICE gomes.pdf: 3188724 bytes, checksum: c4156187d61efe808b3d021846f674dd (MD5) Previous issue date: 2010-08-31 / The plant genetic resources stored ex situ are considered as a genetic repository, and are raw material for the development of the world agriculture. In rice, despite its high genetic variability, the lack of information of accessions to compose a databank prevents its use to help the choice of genitors for the breeding programs. The Embrapa Rice Core Collection (ERiCC) was developed from 10,000 accessions from Embrapa GeneBank, and it was set up by 550 accessions, divided in three subsets: 1) 94 lines and cultivars from Brazil (LCB); 2) 148 lines and cultivars from abroad (LCI); and 3) 308 traditional varieties (VT), obtained from germplasm collection expeditions in Brazil. This work aimed: 1) to evaluate the extension of genetic variability of 550 accessions from ERiCC by means of agronomic traits characterization using mixed models and multivariate statistics; 2) to perform a comparative analysis of the genetic divergence considering the agronomical and SSR markers characterizations; and 3) to identify the genotypes with higher genetic diversity and with the best agronomic performances, aiming to promote the most efficient use of such germplasm in breeding programs. The agronomic characterization of 550 accessions was performed in nine field experiments, evaluating 18 phenological-agronomic traits. The data were analyzed using the mixed linear and AMMI models. There was wide variation range of genotypical values for most evaluated traits. In different environments, it was observed VT accessions among the high-yielding materials, demonstrating the potential of this group of germplasm, particularly important due to its high genetic variability, to contribute to the development of cultivars regionally adapted. The AMMI approach allowed a good discrimination of ERiCC rice genotypes in relation to the adaptive performance, identifying the accessions CA880078, CA990001, CA870071 (subset VT), and CNA0009113 (LCI) as having good yield and broad adaptation to distinct environments. The comparative analysis of genetic diversity between agronomic and molecular data was performed using the 242 lines and cultivars accessions from ERiCC, which were characterized by 86 fluorescent SSR markers, and five agronomic traits with genotypic values predicted (values without from the effects of interaction genotypes x environment, from a joint analysis of nine experiments. The genetic divergence among accessions was estimated by the average Euclidian distance for phenotypical data, and by the Rogers modified by Wright (RW) genetic distance. The datasets were jointly analyzed by descriptive and multivariate statistics, using correlation analyses from hierarchical grouping of Ward and UPGMA methods. The phenotypical and molecular data showed a broad distribution of dissimilarity indexes, despite they showed different patterns of variation between them. Low molecular distances were associated to low phenotypical distances, however to high molecular distances, occurred a high broad range of phenotypical variation. The correlation between genetical and phenotypical dissimilarities was significant for both lowland and upland accessions, despite with different values (r=0.156 and r=0.409, respectively). Due to the low relation between phenotypical and molecular data, the analysis of genotypes to be used in breeding programs must include both evaluations to a better accession characterization. Considering the high yielding accessions, the higher molecular distances were identified among the accessions from lowland system of cultivation, among which BR IRGA 413 and CNA0005014, BR IRGA 413 and CNA0005853, and CNA0004552 and CNA0005014. Considering the upland accessions, maximum genetic distances were identified in CNA0000482 and CNA0006422, CNA0001006 and CNA0006422, and CNA0001006 and CNA0003490. The molecular analysis was able to identify accessions with reduced genetic relationship, that if used as genitors, will result in a progeny with a high probability to find new allelic combinations. On the other hand, the phenotypical characterization is important to identify accessions not just genetically divergent, but with superior agronomic trait performances for breeding programs. The results of this work will permit to increase the activities related to the characterization of accessions from rice Genebank, giving support of breeding programs to choose the best accessions to obtain new cultivars, with favorable traits, and broad genetic basis. In addition, a continuous program of phenotypical and molecular characterization of germplasm will be able to identify accessions to increase the genetic variability of ERiCC. / Os recursos genéticos vegetais armazenados ex situ são considerados reservatórios de genes e funcionam como matéria-prima para o desenvolvimento da agricultura mundial. Na cultura do arroz, apesar da extensa variabilidade genética existente, a deficiência de informações que integrem dados que possam efetivamente auxiliar na escolha de genótipos importantes para os programas de melhoramento constitui o principal fator que limita a utilização mais ampla dos acessos armazenados nos bancos de germoplasma. A Coleção Nuclear de Arroz da Embrapa (CNAE) representa a variabilidade genética de mais de 10 mil acessos constituintes do Banco Ativo de Germoplasma (BAG) da Embrapa Arroz e Feijão, e é composta por 550 acessos subdivididos em três estratos: 1) 94 Linhagens e Cultivares Brasileiras (LCB), provenientes de programas de melhoramento de instituições brasileiras; 2) 148 Linhagens e Cultivares Introduzidas (LCI), provenientes de programas de melhoramento de outros países; e 3) 308 Variedades Tradicionais (VT), que reúne acessos obtidos por expedições de coleta de germoplasma realizadas em vários estados do Brasil. Este trabalho teve como principais objetivos: 1) avaliar a extensão da variabilidade genética dos 550 acessos pertencentes à CNAE por meio da caracterização agronômica via metodologias de modelos mistos e estatísticas multivariadas; 2) realizar a análise comparativa da divergência genética entre acessos, determinada pela avaliação de caracteres agronômicos e marcadores moleculares SSR; e 3) identificar os genótipos com maior diversidade genética e com melhores atributos agronômicos, a fim de indicar uma melhor utilização destes recursos genéticos em programas de melhoramento. Na caracterização agronômica foram avaliados 550 acessos em experimentos conduzidos em nove locais no Brasil, envolvendo um total de 18 caracteres fenológico-agronômicos. Os dados foram analisados empregando-se a abordagem de modelos lineares mistos e modelo AMMI de análise. Verificou-se grande amplitude de variação dos valores genotípicos para a maioria dos caracteres avaliados. Nos diferentes ambientes, houve ocorrência de genótipos do estrato VT entre os mais produtivos, o que demonstra o potencial deste grupo de germoplasma, particularmente importante por sua grande variabilidade genética, em contribuir para o desenvolvimento de cultivares regionalmente adaptadas. A abordagem AMMI permitiu uma boa discriminação dos genótipos de arroz da CNAE quanto ao seu comportamento adaptativo, identificando os acessos CA880078, CA990001, CA870071 (do estrato VT), e CNA0009113 (LCI) com estabilidade, produtividade satisfatória e ampla adaptação à diferentes ambientes. Para a análise comparativa da diversidade genética entre dados agronômicos e moleculares foram considerados 242 acessos da CNAE, os quais foram caracterizados utilizando-se 86 marcadores SSR fluorescentes, sendo que para os dados agronômicos, foram realizadas análises conjuntas dos experimentos e considerados os valores genotípicos preditos de cinco caracteres (valores livres dos efeitos de interação genótipos x ambientes). A divergência genética entre os acessos foi estimada pelo procedimento de distância Euclidiana média para os dados fenotípicos, e por meio da distância de Rogers modificada por Wright (RW) para os dados moleculares, analisando-se os conjuntos de dados por meio de estatísticas descritivas e multivariadas, empregando-se análises de correlação entre matrizes de dissimilaridade e análises de agrupamento hierárquico de Ward e UPGMA. Os dados fenotípicos e moleculares apresentaram uma ampla distribuição dos índices de dissimilaridade, embora tenham apresentado diferentes padrões dessa variação. Baixas distâncias moleculares estiveram associadas a baixas distâncias baseada nos valores genotípicos, no entanto para elevadas distâncias moleculares houve ocorrência de ampla escala de variação fenotípica. A correlação entre as dissimilaridades genéticas e valores genotípicos foi significativa tanto no conjunto de acessos irrigados quanto no de sequeiro, porém, com diferentes magnitudes (r=0,156 e r=0,409, respectivamente). Devido esta baixa relação entre os dados fenotípicos e moleculares, o estudo de genótipos para fins de uso no melhoramento genético deve incluir ambas avaliações para a melhor caracterização dos acessos. Entre os materiais mais produtivos, as maiores distâncias moleculares foram identificadas entre os genótipos do sistema de cultivo irrigado, dentre eles BR IRGA 413 e CNA0005014, BR IRGA 413 e CNA0005853, e CNA0004552 e CNA0005014. Entre os materiais de sequeiro, máximas distâncias genéticas foram identificadas entre os acessos CNA0000482 e CNA0006422, CNA0001006 e CNA0006422, e CNA0001006 e CNA0003490. A análise molecular permitiu que fossem identificados genótipos de vínculo genético reduzido, que quando utilizados como parentais em cruzamentos, possibilitarão que as progênies obtidas apresentem maiores chances de combinações alélicas inéditas. Por sua vez, a caracterização fenotípica tem papel fundamental na identificação de materiais que além de divergentes, apresentem desempenho agronômico superior para os programas de melhoramento. Os resultados deste trabalho permitirão aumentar eficazmente as atividades relacionadas à caracterização de acessos do Banco Ativo de Germoplasma de arroz, subsidiando os programas de melhoramento na escolha de genótipos a serem utilizados para a obtenção de novas cultivares, com características favoráveis, de ampla base genética. Em adição, um programa contínuo de caracterização fenotípica e molecular de germoplasma permitirá ainda a escolha de acessos para a ampliação da variabilidade genética da CNAE.
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Caracterização genética e morfoagronômica de germoplasma de Stylosanthes guianensis (Aubl.) Sw. / Genetic and morpho-agronomic characterization of Stylosanthes guianensis (Aubl.) Sw. germplasm.

KARIA, Cláudio Takao 21 August 2008 (has links)
Made available in DSpace on 2014-07-29T14:52:05Z (GMT). No. of bitstreams: 1 claudio takao karia.pdf: 2242096 bytes, checksum: 8b502fdb3ff4995409e0345270eaaed3 (MD5) Previous issue date: 2008-08-21 / Plant genetic resources maintained ex situ, in germplasm banks, are few used in agricultural systems and genetic plant breeding programs. One of the main reasons of this incipient use is the difficulty to obtain information about stored accessions, especially the characterization and preliminary evaluation data. Stylosanthes guianensis is a predominantly self-pollinated and diploid species, which has a great number of this stored accessions and potential for use in agricultural systems. There are approximately one thousand accessions of the S. guianensis in Embrapa&#8223;s germplasm bank. Moreover, only one genotype of this species is now available to commercial growers in Brazil, the cultivar Mineirão. To promote the use of these resources, this study aimed to characterize accessions of S. guianensis, stored in the germplasm bank of Embrapa, using morpho-agronomic traits and microstellites markers (SSR). In morpho-agronomic characterization 535 accessions were evaluated using 23 quantitative traits. The data were analyzed by a principal component analysis (PCA), the Ward's agglomerative hierarchical clustering method, and by univariate analysis of variance, associated to a Tukey test for comparisons among means of the established groups. Thirteen similarity accession groups were established, five of them were considered the ones with the highest potential use in agricultural systems. Regarding these potential groups, it is possible to reduce from 535 to 126 accessions to be thoroughly evaluated. The molecular characterization was made in 437 accessions, using seven microsatellites fluorescent primers, and the detection of the DNA fragments generated by PCR (Polimerase Chain Reaction) was accomplished by a capillary electrophoresis. The seven loci provided 45 alleles (6.43 alleles/locus), of which four were private alleles. Both, principal coordinates analysis and cluster analysis, in this case, by UPGMA agglomerative method, showed a tendency to group accessions together by botanical varieties (canescens, guianensis and pauciflora), except for the microcephala variety. The correlation between the genetic and morpho-agronomic dissimilarities was highly significant, however, it was of low magnitude (r = 0.23, P &#8804; 0.0001). This indicates that both evaluations are important and should be performed to achieve a more complete characterization of these accessions and, possibly, of the species. Taking account the germplasm accessions with agronomic potential, selected based on the morpho-agronomic evaluation, several of them presented significant genetic dissimilarities to the Mineirão cultivar. These accessions should be better assessed for agronomic traits, and crossed with this cultivar in breeding programs of the species. The results of this research will allow increasing the efficiency and effectiveness of the germplasm bank activities, helping the choice of genotypes to be tested in agronomic evaluations, and stimulating further researches with these genetic resources. / Os recursos genéticos vegetais armazenados ex situ, em geral, são pouco utilizados nos sistemas de produção e no melhoramento genético de plantas. Um dos principais motivos deste uso incipiente é a dificuldade de se obterem as informações sobre os acessos armazenados, sobretudo os dados de caracterização e avaliação preliminar. A espécie Stylosanthes guianensis, diplóide e preferencialmente autógama, possui grande quantidade desses acessos e potencial de utilização em sistemas agrícolas. Somente no Banco de Germoplasma da Embrapa existe uma coleção com cerca de mil acessos registrados de S. guianensis. Por outro lado, apenas um genótipo dessa espécie é hoje comercializado no Brasil, a cultivar Mineirão. Para promover a utilização desses recursos, o presente trabalho teve como objetivo caracterizar os acessos de S. guianensis, armazenados no Banco de Germoplasma da Embrapa, utilizando-se caracteres morfoagronômicos e marcadores de locos microssatélites (SSR). Na caracterização morfoagronômica, foram avaliados 535 acessos acerca de 23 caracteres quantitativos. Os dados correspondentes foram estatisticamente investigados empregando-se a análise de componentes principais, a análise de agrupamento, pelo método aglomerativo de Ward, e a análise de variância (univariada), associada ao teste de Tukey, para comparar as médias dos grupos identificados. Foram estabelecidos treze grupos de acessos similares, dos quais, cinco foram considerados de maior potencial para a utilização nos sistemas agrícolas. Considerando-se apenas os grupos potenciais, é possível reduzir o número de acessos a serem avaliados mais detalhadamente, de 535 para 126 acessos. Na caracterização genético-molecular foram considerados 437 acessos da coleção, utilizando-se sete primers microssatélites, marcados com fluorescência, e a detecção dos fragmentos de DNA obtidos via PCR (reação da polimerase em cadeia) foi feita por meio da técnica de eletroforese em capilar. Os sete locos produziram 45 alelos (6,43 alelos/loco), dos quais quatro foram alelos privados. Tanto na análise de coordenadas principais, como na análise de agrupamento, neste caso pelo método UPGMA, os acessos demonstraram tendência de se reunirem em grupos, conforme as variedades botânicas da espécie (canescens, guianensis e pauciflora), exceto para a variedade microcephala. A correlação entre as dissimilaridades genéticas e morfoagronômicas foi altamente significativa, porém, de baixa magnitude (r = 0,23; P &#8804; 0,0001), indicando que ambas as avaliações são importantes e devem ser realizadas para a melhor caracterização desses acessos e, possivelmente, da espécie. Considerando-se os grupos com potencial agronômico, selecionados na avaliação morfoagronômica, identificaram-se acessos geneticamente bastante dissimilares da cultivar Mineirão, que devem ser mais bem avaliados agronomicamente, para compor possíveis cruzamentos com essa cultivar, em programas de melhoramento da espécie. Assim, os resultados deste trabalho permitirão aumentar a eficiência e a eficácia das atividades no Banco de Germoplasma em estudo, subsidiar a escolha de genótipos a serem testados em avaliações agronômicas, podendo, ainda, estimular outras pesquisas com esses recursos genéticos.
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Defining the genetic and physiological basis of Triticum sphaerococcum Perc.

Josekutty, Puthiyaparambil Chacko January 2008 (has links)
ABSTRACT Triticum sphaerococcum (AABBDD, 2n = 6x = 42) is a land race of wheat known from the Indian subcontinent. It has several favourable characters including short and strong culms, hemispherical grains with a shallow crease (that may increase the yield of white flour), higher protein content compared to bread wheat (T. aestivum), and resistance to drought, and yellow rust caused by Puccinia striiformis. However, an unfavourable characteristic of T. sphaerococcum is its lower yield compared to bread wheat. Being a land race, the sphaerococcum wheat is poorly studied. This study was undertaken to increase knowledge of the physiology and genetics of this land race and determine if it may be possible to separate the favourable characters of T. sphaerococcum from its unfavourable characters. Plant height in bread wheat is controlled by many genes. ‘Reduced Height’ (Rht) genes which differ in their response to externally applied gibberellic acid (GA3) are responsible for the short stature of modern bread wheat varieties. Therefore, GA3 was used to probe the relationship between the semidwarf sphaerococcum phenotype and the Rht gene. T. sphaerococcum variety Sp5 showed a unique “seedling response” to externally applied GA3 when compared with T. aestivum varieties harbouring Rht1, Rht2, Rht8, Rht12, Rht13 or Rht18 alleles. A mapping population of doubled haploids was generated through wide hybridisation of F1 (Sp5 x Otane) with Zea mays. A genome-wide scan of Sp5 and Otane (parents) using 348 microsatellite (SSR) markers showed that only 169 of these markers (49%) were polymorphic between the parents. A DArT profiling yielded 348 markers that were polymorphic between the parents. Microsatellite markers and DArT markers were used to create a genetic map. The mapping population was phenotyped and a quantitative trait loci (QTL) analysis was performed for component traits of the complex sphaerococcum trait including plant height, spike length, awn length, yield, grain shape and crease size. Results of the QTL analysis indicated that it may be difficult to separate the favourable characters of T. sphaerococcum from its unfavourable characters through mutation because the component traits of the complex sphaerococcum trait may be under pleiotropic control of the Sp gene. The hypothesis that T. sphaerococcum originated through a mutation in T. aestivum was tested through induced mutation using gamma rays. Mutants from sphaerococcum-type to aestivum-type were isolated and phenotyped. Sphaerococcum-type mutants also were isolated and characterised from mutated aestivum-type wheat suggesting a possible origin of T. sphaerococcum through a mutation in T. aestivum.
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Technical Verification and Validation of TIS-B using VDL Mode 4

Fredriksson, Daniel, Schweitz, Anders January 2004 (has links)
<p>This report is a technical verification and validation of Traffic Information Service Broadcast (TIS-B) using the data link VDL Mode 4. </p><p>The main objective of the report is to examine the usefulness of TIS-B considering the results from tests performed in the Stockholm Terminal Area and for the Advanced Surface Movement Guidance and Control System (A-SMGCS) at Arlanda airport. The results are compared with the requirements that have been set by the standardisation organisations ICAO, RTCA, Eurocontrol and Eurocae. TIS-B is however such a new concept, so most of the operational requirements have not yet been defined.</p><p>The process for performing the evaluation of TIS-B involves three stages: </p><p>· Study the requirements on TIS-B, ADS-B, radar and A-SMGCS. </p><p>· Verify TIS-B by performing tests at Arlanda airport. </p><p>· Validate the test results through analysis. </p><p>A theoretical study of slot allocation optimisation is performed to decide how the slot allocation is to be implemented. </p><p>The report includes a Functional Hazard Analysis (FHA). The FHA is done to see if the applications for TIS-B are ready for implementation or if more hazard preventing actions has to be taken, before any operational actions can be performed. </p><p>The report also involves a theoretical introduction to Air Traffic Management (ATM), Surveillance techniques and TIS-B. </p><p>All parts included in the report results in conclusions and recommendations regarding the TIS-B service.</p>

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