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Angl. resumé

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Maize is the staple food for the majority of Tanzanians. However, maize production in the Southern highlands of Tanzania (SHT) is highly reduced by gray leaf spot disease (GLS) caused by the fungus Cercospora zea maydis. GLS reduces grain yield, kernel and silage quality. The most common GLS control methods in Tanzania include amongst others; fungicides, crop rotation, field sanitation, host resistance. These methods except host resistance are, however, either expensive or less effective or unsafe to the environment. Furthermore, conventional breeding strategies are not very effective for traits, which are lowly inherited such as GLS resistance. Lastly, to date there are few GLS resistant commercial hybrids in SHT. Thus, this study aimed to produce more commercial GLS resistant hybrids, increase farmers’ hybrid choices of growing genetically different GLS insensitive hybrids, which will also provide a constant supply of GLS resistant maize cultivars in case of GLS resistance breakdown due to new GLS pathotypes. This research combined conventional breeding with molecular technologies to increase the efficacy of selecting GLS resistant hybrids and assist breeders in predicting best inbred combinations for commercial hybrid production. Studies conducted to meet the main aims were on; the prediction of best line combiners and heterosis in Tanzanian maize breeding lines through the use of amplified fragment length polymorphism, (AFLP), an association of AFLPs and the performance of phenotypic traits in maize, evaluation of maize hybrids for gray leaf spot resistance in multienvironments and finally a preliminary study on gray leaf spot PCR-based marker development with the long term objective of implementing cleaved amplified polymorphic markers (CAPS) in a marker assisted selection (MAS) strategy in the SHT maize breeding programme. Results from the study revealed that pairwise GD (genetic distance) of the lines varied from a GD of 0.13 to 0.5. High coancentry coefficients were exhibited by these lines. Joint data analyses showed that there were tighter associations between line GD and F1 traits or MPH in the intergroup than in the intragroup crosses. Combined analyses revealed that hybrids 48, 90 and 45 recorded higher stable yields and consistently low GLS scores in multienvironments. Fifteen CAPS marker bands were identified that are putatively linked to the GLS resistant genes. In summary, it was noted that strong selection during inbreeding programs should be avoided as it reduces germplasm variability. Local landraces/varieties can be improved by introgressing desirable genes into them. AFLP marker system could be effectively used for inbred genetic diversity studies in Tanzania. Intergroup crosses with high GD-MPH should be the main target for commercial hybrid production but field testing of them is inevitable to confirm their yielding potentials. Intergroups and intragroup crosses with low GD-MPH should be discarded to avoid field costs. Better F1 hybrid performance predictions can be achieved by integrating inbred GD and F1 phenotypic data. Hybrids with low GLS/high GLS resistance could be used to produce other breeding populations. Hybrids 45, 48 and 90 can be commercially preleased. Lastly a study to characterize the GLS fungus in the SHT is imperative since information on virulence of isolates is needed for long term breeding strategies against the fungus. Finally, the SHT maize germplasm has potential GLS resistant inbred lines which could be used in the deployment of genes to susceptible lines and in the development of commercial GLS resistant hybrids/open pollinated varieties/doubled haploid hybrids. / Thesis (PhD)--University of Pretoria, 2008. / Genetics / unrestricted

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / This work aimed at building a management dendrogram and determining the appropriate density for management of stands of Pinus elliottii in central region of the Rio Grande do Sul. To do that, stands in maximum stock, in different ages, located in the campus of Universidade Federal de Santa Maria and neighborhoods, were used. The dendrometric variables used in the calculation process were obtained from sample units with temporary characteristic, considering the method of determination of the punctual density proposed by Spurr, and isolated trees, with crowns in free growth. The maximum population density was estimated by the Reineke method, with an angular coefficient of -1,92009. The density in number of trees for the beginning of the total occupation of the dossal was estimated taking into account the crown areas, which were obtained from a lineal model estimator of crown diameter in function of the dap, fit for variables from trees in free growth. The construction of the dendrogram was in function of the basal area, the number of trees per hectare and the tree diameter with medium basal area. The density levels were determined proportionally to the maximum density for stands density index (IDP), in clusters of index 200, from the maximum IDP, 1200, to the minimum, 400. The appropriate density for management was found by calculation process and adjusted by the observation of two stands. Results indicate the maintenance of the density between IDP 600 and 840 for the production of wood of great dimensions. Plans of management with different initial densities and number of self-thinning interventions were elaborated, showing that the dendrogram is an efficient tool, able to assist the elaboration of the management plan, with production estimates for self-thinning and final cut. / Este trabalho teve como objetivos construir um dendrograma de manejo e determinar a densidade adequada para manejo de povoamentos de Pinus elliottii para a região Central do Rio Grande do Sul. Para tanto, foram utilizados povoamentos em estoque máximo, em diferentes idades, localizados no campus da Universidade Federal de Santa Maria e proximidades. As variáveis dendrométricas foram obtidas de unidades amostrais de caráter temporário pelo método de determinação da densidade pontual proposto por Spurr, e de árvores isoladas, com copa em crescimento livre. A máxima densidade populacional foi estimada pelo modelo de Reineke, com um coeficiente angular de -1,92009. A densidade em número de árvores para o início da ocupação total do dossel foi obtida através de um modelo linear estimador de diâmetro de copas em função do dap, ajustado com variáveis obtidas de árvores em crescimento livre. O dendrograma foi construído em função da área basal, do número de árvores por hectare e do diâmetro da árvore de área basal média. Os níveis de densidade foram determinados, proporcionalmente, à máxima densidade por índice de densidade do povoamento (IDP), em classes de índice 200, desde o IDP máximo, 1200, até o mínimo, 400. A densidade adequada para manejo foi ajustada por processo de cálculo e pela observação de dois povoamentos. Os resultados obtidos indicam a manutenção da densidade entre o IDP 600 e 840 para a produção de madeira de grandes dimensões. Foram elaborados planos de manejo com diferentes densidades iniciais e número de intervenções de desbaste, demonstrando que o dendrograma é uma ferramenta eficiente, capaz de auxiliar na elaboração de planos de manejo, com estimativas de produção para desbastes e corte final.

Submitted by Ricardo Cedraz Duque Moliterno (ricardo.moliterno@uefs.br) on 2015-11-11T23:45:15Z No. of bitstreams: 1 Disserta??o Soniane.pdf: 4275209 bytes, checksum: ccb64680a02e7e062aaddf493949e519 (MD5) / Made available in DSpace on 2015-11-11T23:45:15Z (GMT). No. of bitstreams: 1 Disserta??o Soniane.pdf: 4275209 bytes, checksum: ccb64680a02e7e062aaddf493949e519 (MD5) Previous issue date: 2013-01-25 / The objectives of this study were to obtain and evaluate interspecific hybrids of the genus Psidiumto resistance to M. enterolobii and analyze the genetic variability of accessions of guava and ara?azeiros of the active germplasm bank of Embrapa Semi-Arid based on microsatellites, to guide genetic resources and breeding programs, emphasizing crosses of guava with other Psidium species.The crosses were performed when the calyx ruptured on the flower buds. When the plants reached15 to 20 cm tall, they were inoculated with a suspension containing 10,000 nematode eggs. Four months after inoculation, the soils were removed from the plants for individual evaluation of the number of galls, number of eggs and reproduction factor (RF). Genotyping was performed with two and 13 microsatellite loci in hybrids and Psidium accessions, respectively. Total DNA was extracted by the CTAB 2x method and PCR products were analyzed by denaturing polyacrylamide gel 6%, stained with silver nitrate. Interspecific hybrids between GUA 161 PE P guajava x ARA 138 RR P. guineensewere highly tolerant to nematodes, with growth similar to the guava, and demonstrated high compatibility when grafted with the cultivar 'Paluma'. The 61 accessionsPsidiumaccessions showed similarity coefficient ranging from 0.75 to 1.00 and the dendrogram presented co-phenetic value of 0.85. Genetic variability was considered high ?ST=0.238 and it was observed formation of five groups at a cutoff of 83% similarity. The genetic similarity among P.guineense and some guava accessions were above 80%, suggesting greater possibility to obtain interespecific hybrids among these two species. / Os objetivos deste trabalho foram obter e avaliar h?bridos interespec?ficos do g?nero Psidium para resist?ncia ao M. enterolobii e analisar a variabilidade gen?tica de acessos de goiabeiras e ara?azeiros do banco ativo de germoplasma da Embrapa Semi?rido, com base em microssat?lites, para fornecer subs?dios para programas de recursos gen?ticos e de melhoramento com ?nfase para cruzamentos de goiabeira com outras esp?cies do g?nero Psidium.Os cruzamentos foram realizados quando os bot?es florais apresentavam ruptura do c?lice.Quando as plantas atingiram 15 a 20 cm de altura, foi realizada a inocula??o com suspens?o contendo 10.000 ovos do nematoide. Quatro meses ap?s a inocula??o, foi removido o solo das plantas para avalia??o individual para n?mero de galhas, n?mero de ovos e fator de reprodu??o (FR). A genotipagem foi feita com dois e 13 locos de microssat?lites, nos h?bridos e nos acessos de Psidium. O DNA total foi extra?do pelo m?todo CTAB 2x e os produtos de PCR foram analisados em gel de poliacrilamida desnaturante 6% e corados com nitrato de prata. H?bridos interespec?ficos entre GUA 161 PE de P. guajava x ARA 138 RR de P. guineense foram altamente resistentes ao nematoide, apresentando crescimento similar ao da goiabeira, e demonstrado alta compatibilidade quando enxertada com a cultivar ?Paluma?.Os 61 acessos de Psidium apresentaram coeficiente de similaridade variando de 0,75 a 1,00. O dendrograma apresentou valor co-fen?tico de 0,85. A variabilidade gen?tica foi considerada alta 0,238(?ST)e observou-se forma??o de cinco grupos no ponto de corte de 83% de similaridade.A similaridade gen?tica entre P. guineense e alguns acessos de goiabeira foi superior a 80%, indicando maior possibilidade de sucesso em cruzamentos interespec?ficos entre essas duas esp?cies.

This thesis deals with identification of wine yeasts isolated during fermentation process of wine cider and grapes of Sauvignon grape variety, grown in the integrated vineyard. The identification and taxonomic classification is faster and easier due to the progress of molecular methods. In this thesis PCR-RFLP method was used for identification of yeasts. Sequences of DNA specific for each species were analysed. These sequences were amplified by means of PCR method and by using ITS1 and ITS4 primers. In following step, they were put through the restrictiction analysis with five restriction endonucleases. Fragments of DNA were separated by horizontal electrophoresis. The electrophoreograms were evaluated by BioNumerics software and final dendrogram representing genetics similarity of isolated yeasts was created by using UPGMA claster analysis. The basic information about yeasts and their identification by molecular methods are described in the theoretical part of this thesis.

This thesis deals with identification of yeasts isolated during spontaneous fermentation of grape juice. For analysis the Pinot Noir grape variety grown in the integrated vineyard was chosen. In the theoretical part of this thesis basic information about yeasts are described. Genera of yeasts that occurs during fermentation process and methods based on PCR are also described. In this thesis PCR-RFLP method was used for identification of yeasts. The amplification of the 5,8S-ITS rDNA sequence was performed by the polymerase chain reaction with use of the primers ITS1 and ITS4. The restriction analysis was performed by applying five restriction endonucleases: HaeIII, HinfI, Taq?, AluI, MseI. The amplicons were split into fragments which length and number are typical for the particular species. These fragments were identified by agarose gel electrophoresis and electrophoreograms were evaluated by BioNumerics software. Dendrograms representing genetic similarity of isolated wine yeasts were created by using UPGMA cluster analysis.

This thesis provides a new hierarchical clustering algorithm for graphs, named Paris, which can be interpreted through the modularity score and its resolution parameter. The algorithm is agglomerative and based on a simple distance between clusters induced by the probability of sampling node pairs. It tries to approximate the optimal partitions with respect to the modularity score at any resolution in one run. In addition to the Paris hierarchical algorithm, this thesis proposes four algorithms that compute rankings of the sharpest clusters, clusterings and resolutions by processing the hierarchy output by Paris. These algorithms are based on a new measure of stability for clusterings, named sharp-score. Key outcomes of these four algorithms are the possibility to rank clusters, detect sharpest clusterings scale, go beyond the resolution limit and detect relevant resolutions. All these algorithms have been tested on both synthetic and real datasets to illustrate the efficiency of their approaches. / Denna avhandling ger en ny hierarkisk klusteralgoritm för grafer, som heter Paris, vilket kan tolkas av modularitetsresultatet och dess upplösningsparameter. Algoritmen är agglomerativ och är baserad på ett enda avstånd mellan kluster som induceras av sannolikheten för sampling av nodpar. Det försöker att approximera de optimala partitionerna vid vilken upplösning som helst i en körning. Förutom en hierarkisk algoritm föreslår denna avhandling fyra algoritmer som beräknar rankningar av de bästa grupperna, kluster och resolutioner genom att bearbeta hierarkiproduktionen i Paris. Dessa algoritmer bygger på ett nytt koncept av klusterstabilitet, kallad sharpscore. Viktiga resultat av dessa fyra algoritmer är förmågan att rangordna kluster, upptäcka bästa klusterskala, gå utöver upplösningsgränsen och upptäcka de mest relevanta resolutionerna. Alla dessa algoritmer har testats på både syntetiska och verkliga datamängder för att illustrera effektiviteten i deras metoder.