Made available in DSpace on 2014-06-11T19:31:37Z (GMT). No. of bitstreams: 0 Previous issue date: 2007-06-01Bitstream added on 2014-06-13T19:41:57Z : No. of bitstreams: 1 messetti_avl_dr_botfca.pdf: 1122280 bytes, checksum: 539d4ccf859c8ac755f6adba3eeb14de (MD5) / Este trabalho foi desenvolvido com os objetivos de avaliar a divergência genética de 12 populações de girassol do Banco de Germoplasma da EMBRAPA /Soja de Londrina por meio de técnicas multivariadas; divulgar tópicos recentes e interessantes das técnicas multivariadas que não são explorados nos trabalhos científicos de melhoramento de plantas e orientar a escolha de populações para cruzamentos nos programas de melhoramento genético da cultura de girassol. O modelo experimental constitui-se de delineamento bloco casualizado envolvendo 12 variedades de girassol avaliadas sob cinco caracteres morfoagronômicos. Por meio da análise univariada foi verificada diferença significativa (p<0,05) dos tratamentos para todos caracteres. A aplicação dos componentes principais permitiu a redução bidimensional, com a explicação de 82,5% da variação total. O número de componentes foi avaliado pelo critério de Kaiser e critério Scree-test. A visualização da divergência genética proporcionada pelos escores das duas primeiras variáveis canônicas, evidenciaram grupos geneticamente diferentes. Ambas técnicas apontaram concordância nos resultados. Com base nas estimativas da distância Mahalanobis e distância euclideana foi realizada a análise de agrupamento adotando-se três algoritmos hierárquicos. Para determinar o número de grupos adotou-se o dendrograma, a análise do nível de fusão e a análise do comportamento de similaridade. Para validação utilizou-se o critério de Wilks dentro de cada grupo e gráficos multivariados auxiliaram na interpretação dos resultados. Pode-se concluir pela existência da divergência genética, detectando-se quatro grupos geneticamente diferentes e caracterizado pelos escores médios. / The objective of this work was to evaluate genetic divergence in 12 sunflower populations from EMBRAPA/ Londrina Soybean Germplasm Bank, using multivariate techniques, to discuss recent and interesting topics related to the multivariate techniques donþt found in plant improvement scientific papers, and to offer guidelines on how to choose populations for sunflower genetic improvement crossing programs. The experiment included a totally block casualized design, with twelve sunflower varieties, evaluated according to 5 morphoagronomics traits. The univariate analysis showed a significant difference (p<0,05) among treatments for all the traits. Application of main components allowed for a bi-dimensional reduction, with 82,5% of the total variation. The number of components were evaluated by the Kaiser and Scree-test criteria. Genetic divergence visualization provided by the two first canonical variables showed genetically different groups. Both techniques showed the same results. Based on Mahalanobis and Euclidean distance estimates, a clustering analysis was carried out using three hierarchicals algorithms. A dendrogram, a fusion level analysis and a similarity behavior analysis were conducted to determine the number of groups. Validation used the Wilks criteria inside each group, while multivariate graphs helped with data interpretation. Results from this study showed genetic divergence in four groups characterized by average/mean scores.

Albugo tragopogonis is responsible for white rust of sunflower. It was first observed in 1929 in South Africa. Recently however, white rust has resulted in lodging exceeding 80% in some sunflower growing areas. Due to the obligate nature of the pathogen, studies of the biology, epidemiology and control of the disease has until now been limited to field trials and observations. Greenhouse trials are needed to understand the infection process, and to examine any resistance mechanisms used by the plant to defend itself against the pathogen. Presently, there is no practical artificial inoculation technique available and effective storage of the fungus is difficult. The purpose of these studies was to find new storage and inoculation techniques. Once the inoculation technique was optimized, the infection process of A. tragopogonis on susceptible and tolerant sunflower genotypes was examined. Infected leaves were collected from sunflower seedlings at the Grain-Crops Institute in Potchefstroom. Infected leaves were covered with plastic bags and freshly cut stems were placed in a cooler box filled with ice water. Some of the infected leaves were also placed in paper bags and allowed to dry for 24 h. Sporangia were collected using a vacuum device and stored in gelatin capsules at -20°C, -70°C or in liquid nitrogen directly after collection or following desiccation for 24 h. Sunflower seedlings at the four-leaf-stage were inoculated with freshly collected sporangia, or sporangia stored for 3, 5, 9, 12 and 15 mo. A zoospore suspension was prepared by allowing 105 sporangia/ml to germinate in distilled water for 3 h at 10°C. The zoospore suspension was then sprayed onto leaves until they were completely wet with a hand held garden spray bottle. Inoculated seedlings were covered with plastic bags to maintain high humidity and placed at 12°C for 16 h and incubated in a greenhouse until symptom development. Infection levels were assessed 10¬14 d after inoculation, using a scale of 1-5, with 1 indicating resistance and 5 indicating severe infection. Infection with fresh sporangia proved to be very consistent. Sporangia stored in capsules immediately after collection at -70°C after desiccation, produced the highest infection. Low levels of infection resulted from storage in liquid nitrogen or directly at -70°C. It is evident that successful storage may be obtained if the sporangia are dried before storage. These techniques to store and inoculate A. tragopogonis have proven to be reliable. Susceptible and tolerant genotypes were inoculated, using the spray bottle inoculation technique described above, to examine the difference in infection of A. tragopogonis. Leaves used for light microscopy were cut into 20 mm2 and those for scanning electron microscopy were cut into 5x5 mm pieces at 2, 4, 6, 8, 10, 12, 24, 36, 48, 72, 96, 120, 144 and 168 h time intervals after inoculation. The epidermis, palisade parenchyma and spongy parenchyma were chronologically stripped using the double-sided tape method. The material for the light microscope was prepared using the whole-leaf clearing and staining technique, the lactophenol-ethanol-analine blue technique and sectioning with freeze microtome. The material for SEM was prepared according to standard procedures and examined with a JEOL 840 SEM at 5 kV. Both the whole-leaf clearing and staining and the lactophenol-ethanol-aniline blue techniques proved to be unsuitable as most of the tissue was damaged by boiling. Sectioning with the freeze microtome was also unsuccessful. The SEM gave the most transparent results. This method gave us the ability to compare results with previous literature and to compare the infection process between of A. tragopogonis in the susceptible (RHA 358) and the tolerant (HYS 33) genotype. / Dissertation (MSc ( Plant Pathology))--University of Pretoria, 2005. / Microbiology and Plant Pathology / unrestricted

Declines in several pollinator species are due to a variety of factors, including pathogens. Incorporating pollinator-friendly plant species into wild and agricultural habitats could reduce the stress of pathogens if food sources act medicinally against pathogens. Previous research demonstrated one domesticated sunflower cultivar (Helianthus annuus) can dramatically reduce a gut pathogen (Crithidia bombi) of the common eastern bumble bee, Bombus impatiens. To ascertain the breadth of this medicinal trait, we tested whether pollen from several H. annuus cultivars and four relatives could also reduce C. bombi infections in B. impatiens. We also investigated whether timing of exposure to sunflower pollen relative to time of infection affected the strength of this medicinal trait. In all experiments, bees were infected and then fed their respective pollen diets for a week before they were dissected to assess infection. In our first experiment, all pollen from Helianthus species and relatives reduced C. bombi cell counts compared to our single species control of buckwheat (Fagopyrum esculentum). In our timing of exposure experiments, a one-time exposure to sunflower pollen present at the time of infection did not lower infection levels. In longer exposure trials, sunflower pollen suppressed C. bombi infection with a strength inversely proportional to the time between treatment and infection. Our results suggest that medicinal pollen may be widespread in the Helianthus genus and potentially throughout the Asteraceae family. Thus, these results provide insights into how strategic plantings of certain floral resources can help mediate and influences pollinator disease dynamics.

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Thesis (MScAgric)--Stellenbosch University, 2003. / ENGLISH ABSTRACT: 1. The effect of heat-treatment and dehulling of full-fat soya (Glycine max) on AMEn' amino acid availability and broiler performance. Heat treatment and dehulling of full-fat soya were evaluated in terms of their effect on AMEn, apparent amino acid availability and broiler performance. Four products were tested: raw whole soya (RWS), raw dehulled soya (RDS), extruded whole soya (EWS) and extruded dehulled soya (EDS). Trials were conducted to determine AMEn values and apparent amino acid availability of the products. A 42-day broiler trial was conducted to measure the effect of extrusion and dehulling on broiler performance. Test products were added to the diets at levels up to 263.2 g/kg in the starter diet and 260.0 g/kg in the finisher diet. Results indicated that extrusion cooking improved AMEn and apparent amino acid availability. This was reflected in the improved performance of broilers fed extruded soya as compared to raw soya. Increasing amounts of RWS and RDS led to decreases in mass and intake and poor feed conversion ratio (FeR) due to the presence of anti-nutritional factors. Broilers fed EWS were heavier, consumed more feed and had better FeR than those fed RWS or RDS. Dehulling improved AMEn (EWS: 13.75 MJ/kg vs EDS: 15.09 MJ/kg) and rendered a product with slightly higher levels of total amino acids. Broiler performance did not reflect this as there was no difference in mass, intake or FeR between broilers fed increasing levels of EWS or EDS. Lysine and arginine were less available in EDS than EWS indicating the possible over-cooking of EDS. Levels of EWS and EDS of 263.2 g/kg in the starter and 260.0 g/kg in the finisher supported maximum broiler performance. 2. The effect of heat-treatment and dehulling of full-fat sunflower (Helianthus annuus) on AMEm amino acid availability and broiler performance. Heat treatment and dehulling of full-fat sunflower were evaluated in terms of their effect on AMEn, apparent amino acid availability and broiler performance. Four products were tested: raw whole sunflower (RWSF), raw dehulled sunflower (RDSF), extruded whole sunflower (EWSF) and extruded dehulled sunflower (ED SF). Trials were conducted to determine AMEn values and apparent amino acid availability of the products. A 42-day broiler trial was conducted to measure the effect of expansion and dehulling on broiler performance. Test products were added to the diets at levels up to 115.0 glkg in the starter diet and 181.5 glkg in the finisher diet. Dehulling rendered a product with higher crude protein, ether extract, amino acid and AMEn values. AMEn was only slightly improved by expansion. The AMEn values obtained were: RWSF: 16.03 MJ/kg, RDSF: 18.87 MJ/kg, EWSF: 16.22 MJ/kg, EDSF: 19.49 MJ/kg. Dehulling had no effect on apparent amino acid availability. Expansion did not affect apparent amino acid availability of dehulled full-fat sunflower but had a negative influence on apparent amino acid availability of whole sunflower seeds. This highlights the possible dangers of reduced protein quality as a result of overprocessing. No differences were observed in terms of mass, intake and feed conversion ratio of broilers fed any of the products during the 42-day broiler growth trial. All products supported optimum broiler performance at levels up to 115.0 glkg in the starter diet. For the finisher diets, optimum performance was maintained at levels of 181.5 glkg, for RDSF and EDSF, while performance of broilers fed RWSF and EWSF was optimal up to 145.2 glkg. / AFRIKAANSE OPSOMMING: 1. Die invloed van hitte-behandeling en ontdopping van volvetsojabone (Glycine max) op SMEm skynbare aminosuur beskikbaarheid en braaikuikenprestasie. Hitte-behandeling en ontdopping van volvetsojabone is ge-evalueer in terme van hul invloed op stikstof gekorrekteerde skynbare metaboliseerbare energie (SMEn) waardes, skynbare aminosuur beskikbaarheid en braaikuikenprestasie. Vier produkte is getoets: rou heel sojabone (RWS), rou ontdopte sojabone (RDS), geekstrueerde heel sojabone (EWS) en geekstrueerde ontdopte sojabone (EDS). Proewe is uitgevoer om die SMEn waardes en skynbare aminosuur beskikbaarheid van die vier produkte te bepaal. Gedurende 'n braaikuikengroeitoets van 42 dae is die invloed van hittebehandeling (ekstrusie) en ontdopping op braaikuikenprestasie gemeet. Die vier toetsprodukte is ingesluit in die aanvangsdieet teen peile van tot 263.2 g/kg en teen peile van tot 260.0 g/kg in die afrondingsdieet. Resultate het getoon dat ekstrusie die SMEn waardes en skynbare aminosuur beskikbaarheid verbeter het. Braaikuikens wat geekstrueerde soja ontvang het, het beter gepresteer as braaikuikens wat rou soja ontvang het. Verhoogte insluitings van RWS en RDS het gelei tot verlagings in massa toename en voerinname en swak voeromsetverhoudings (VOV), as gevolg van die teenwoordigheid van anti-voedings faktore. Braaikuikens wat EWS ontvang het, was swaarder, het meer ingeneem en het beter vav gehad as die wat RWS of RDS ontvang het. Ontdopping het SMEn verhoog (EWS: 13.75 MJ/kg vs EDS: 15.09 MJ/kg) en ontdopte produkte het klein hoeveelhede meer aminosure bevat. Dit het egter nie in braaikuikenprestasie gewys nie. Daar was geen verskille in massa, voerinname en vav tussen braaikuikens wat EWS of EDS ontvang het. Lisien en arginien was minder beskikbaar in EDS as EWS wat op die moontlike oorprosessering van EDS dui. Vlakke van EWS en EDS van 263.2 g/kg in die aanvangsdieet en 260.0 g/kg In die afrondingsdieet het maksimale braaikuikenprestasie ondersteun. 2. Die invloed volvetsonneblosaad van hitte-behandeling (Helianthus annuus) en ontdopping van op SMEo, skynbare aminosuur beskikbaarheid en braaikuikenprestasie. Hitte-behandeling en ontdopping van volvetsonneblomsaad is geevalueer in terme van hul invloed op stikstof gekorrekteerde skynbare metaboliseerbare energie (SMEn) waardes, skynbare aminosuur beskikbaarheid en braaikuikenprestasie. Vier produkte is getoets: rou heel sonneblomsaad (RWS), rou ontdopte sonneblomsaad (RDS), geekspandeerde heel sonneblomsaad (EWS) en geekspandeerde ontdopte sonneblomsaad (EDS). Proewe is uitgevoer om die SMEn waardes en skynbare aminosuur beskikbaarheid van die vier produkte te bepaal. Gedurende 'n braaikuikengroeitoets van 42 dae is die invloed van hitte-behandeling (ekspansie) en ontdopping op braaikuikenprestasie gemeet. Die vier toetsprodukte is ingesluit in die aanvangsdieet teen peile van tot 115.0 g/kg en teen peile van tot 181.5 g/kg in die afrondingsdieet. Ontdopte sonneblomsaad het hoer peile van ruproteien, eter-ekstrak en aminosure as heel sonneblomsaad. SMEn waardes is ook hoer vir ontdopte sonneblomsaad. Hitte-behandeling het SMEn waardes effens verhoog. Die bepaalde SMEn waardes is as volg: RWSF: 16.03 MJ/kg, RDSF: 18.87 MJ/kg, EWSF: 16.22 MJ/kg, EDSF: 19.49 MJ/kg. Ontdopping het geen invloed op skynbare aminosuur bekikbaarheid gehad nie. Skynbare aminosuur beskikbaarheid van ontdopte sonneblomsaad IS me deur hitte-behandeling beinvloed nie, terwyl die van heel sonneblomsaad negatief beinvloed is. Dit beklemtoon die gevare van verswakte proteien kwaliteit as gevolg van oor-prosessering. Geen verskille is opgemerk in terme van massa, voerinname en voeromset verhouding (VOV) tussen die vier produkte gedurende die braaikuikengroeitoets van 42 dae. Alle produkte het maksimale braaikuiken prestasie ondersteun in die aanvangsdieet teen vlakke van 115.0 g/kg. In die afrondingsdieet het RDSF en EDSF optimale braaikuikenprestasie onderhou teen vlakke van 181.5 g/kg, terwyl RWSF en EWSF net t

The project entitled From the energy which is planted to the peasants subjects: The National Program for Production and Use of Biodiesel and its effect in the backwoods of Sergipe , analyzes the contradictions of the National Program for Production and Use of Biodiesel in the backwoods of Sergipe and its effect in the peasants production. The study got back the debate about the discovery of oil as a great energy potential during the Second Industrial Revolution, and later, the increase of consumption through the economic activities, which brought up a shortage context of this resource, responsible for imposing a review of the world energetic base. The demand for a new energetic base is joined with the creation of a new development approach that suggests the rational and sustainable use of natural resources. In this outlook, the continuation of the production model depends on the creation of this new base, and Brazil, created many programs to support the energy production, especially, through agrofuels, whose history brought changes in the Brazilian rural areas. In Sergipe, the National Program for Production and Use of Biodiesel has been introduced in the country since 2007, presenting as an objective, the diesel production through the sunflower cultivation, and making it stand out by the promises of bringing environmental, social and economic benefits. Actually, the National Program for Production and Use of Biodiesel expresses the importance of the context that no structure change is highlighted to definitely stamp out the poverty in the country. In the study area, a program was observed that after spatializing, it went deeper into the vulnerability of the country person to the market guidelines, as the oil seeds production happens under the command of an outside agent, supporting the capitalist relations nowadays. / A pesquisa intitulada Da energia que se planta à sujeição camponesa: O Programa Nacional de Produção e Uso de Biodiesel e seus rebatimentos no Alto Sertão Sergipano , analisam as contradições do Programa Nacional de Produção e Uso do Biodiesel (PNPB) no espaço agrário do Alto Sertão Sergipano e seus rebatimentos na unidade de produção camponesa. O estudo recuperou o debate acerca da descoberta do petróleo como um rico potencial energético na 2ª Revolução Industrial, e posteriormente, o aumento do consumo pelas atividades econômicas, que trouxe à tona um contexto de escassez desse recurso, responsável por impor uma revisão da matriz energética mundial. A situação de demanda por nova matriz energética se coloca ao lado da elaboração de um novo paradigma de desenvolvimento que sugere o uso racional e sustentável dos recursos da natureza. Nesse panorama, a continuidade do modelo de produção depende da criação dessa nova matriz, e o Brasil, criou vários programas para atender a produção de energia, principalmente, a partir de agrocombustíveis, cujas trajetórias trouxeram transformações no espaço rural brasileiro. Em Sergipe, o PNPB vem sendo introduzido no campo desde 2007, apresentando como objetivo a produção de diesel a partir do cultivo do girassol e destacando-se pela promessa de trazer benefícios econômicos, sociais e ambientais. Na realidade estudada, o PNPB expressa a sua importância no contexto em que nenhuma mudança estrutural é apontada para erradicar definitivamente a pobreza no campo. Na área de estudo, observou-se um programa que ao se espacializar, aprofundou a vulnerabilidade do camponês às diretrizes do mercado, à medida que a produção de oleaginosas se realiza sob o comando de um agente externo, atendendo ao momento atual das relações capitalistas.

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