Diss. Linköping : Univ., 2002.

Diss. (sammanfattning) Alnarp : Sveriges lantbruksuniv. / Härtill 4 uppsatser.

Thesis (MSc)--Stellenbosch University, 2011. / ENGLISH ABSTRACT: Sugarcane is a crop that is farmed commercially due to the high amounts of sucrose that is stored within the mature internodes of the stem. Numerous studies have been done to understand sugar metabolism in this crop as well as to enhance sucrose yields. Until now sugarcane improvement strategies have been implemented through either breeding programs or transgenic manipulation. Public mistrust and regulatory hurdles, however, have made the commercialisation of transgenic crops difficult, expensive and timeconsuming. In this thesis two projects will address issues relating to the above. The first will address an effort to increase sucrose accumulation within the sugarcane culm. This was attempted via the expression of an Arabidopsis thaliana vacuolar pyrophosphatase (AtV-PPase) gene, linked to the maize ubiquitin promoter, in sugarcane callus. It was anticipated that increased activity of the tonoplast-bound AtV-PPase will result in increased sucrose accumulation in the vacuole. Transgenic sugarcane callus lines were tested for soluble sugar content which suggested no significant increase in sucrose content. However, this may change upon further assessment of sugarcane suspension cultures and glasshouse plants. The second project was concerned with the development of a novel sugarcane transformation technology that utilises only sugarcane sequences. This ‘cisgenic’ approach to sugarcane transformation will require a native sugarcane promoter, terminator, vector backbone and selection marker. It was attempted to first isolate a functional promoter as well as developing a selection system based on an endogenous selection marker. A promoter was amplified from sugarcane, using primers designed on a sorghum template, and its expression assessed using a GFP reporter gene. Unfortunately expression could not be confirmed in transgenic sugarcane callus. Currently, an alternative approach is followed by using short fragments of constitutively expressed genes to screen sugarcane Bacterial Artificial Chromosome (BAC) libraries to isolate their corresponding promoters. Lastly, it was attempted to develop a selection system for transgenic sugarcane based on resistance to the herbicide chlorosulfuron. A mutant acetolactate synthase (alsb) gene from tobacco, which has shown to confer resistance to the tobacco, was transformed into sugarcane callus. It was anticipated that this gene will confer chlorosulfuron resistance to transgenic sugarcane. If resistance is achieved, the corresponding sugarcane gene will be mutated via site-directed mutagenesis and checked if it also confers resistance to sugarcane. Results showed that although transgenic lines were generated, resistance development is still inconclusive. / AFRIKAANSE OPSOMMING: Suikerriet is ‘n kommersiële gewas wat verbou word as gevolg van die hoë hoeveelhede sukrose wat gestoor word in die volwasse tussenknope van die stam. Verskeie studies is al gedoen om suiker metabolisme in die gewas te ondersoek, sowel as om die sukrose opbrengs te verhoog. Huidige strategieë vir suikerriet verbetering word beywer deur middel van teel-programme of transgeniese manipulasie. Die kommersialiseëring van transgeniese gewasse word egter bemoeilik deur publieke wanpersepsies, sowel as regulatoriese uitdagings. Hierdie tesis beoog om boenoemde kwessies aan te spreek, deur middel van twee projekte. Die eerste projek poog om sukrose akkumulasie in sukerriet te verhoog. Dit was onderneem om die Arabidopsis thaliana vakuolere pirofosfatase (AtV-PPase) geen, wat verbind is met die mielie ubiquitien promoter, uit te druk in suikerriet kallus. Daar was verwag dat die verhoogde aktiwiteit van die tonoplast-gebonde AtV-PPase sal veroorsaak dat meer sukrose in die vakuool akkumuleer. Oplosbare suiker inhoud was getoets in transgeniese suikerriet kallus lyne, maar geen merkbare verhoging in sukrose inhoud was waargeneem nie. Hierdie mag egter verander met verdere ondersoeke in suikerriet suspensie-kulture en glashuis-plante. Die tweede projek het beywer om ‘n nuwe suikerriet transformasie tegnologie te ontwikkel, wat slegs van suikerriet genetiese materiaal gebruik maak. Hierdie ‘cisgeniese’ benadering tot suikerriet transformasie sal ‘n inheemse suikerriet promoter, terminator, vektor ruggraat en seleksie-merker, benodig. Dit was eers beoog om ‘n funksionele promoter te isoleer, sowel as om ‘n seleksie sisteem, gebasseer op ‘n inheemse seleksie merker, te ontwikkel. Deur gebruik te maak van primers wat op ‘n sorghum templaat gebasseer is, was ‘n promotor geisoleer vanuit suikerriet; die uitdrukking hiervan is bepaal deur gebruik te maak van ‘n GFP verklikker geen. Ongelukkig kon uitdrukking nie bevestig word in transgeniese suikerriet kallus nie. Tans word suikerriet Kunsmatige Bakterieële Chromosoom (KBC) biblioteke geskandeer, deur gebruik te maak van geen-fragmente van globaal-uitgedrukte gene, om ooreenstemmende suikerriet promoters te isoleer. Die tweede deel van die cisgeniese projek het beoog om ‘n seleksie sisteem vir transgeniese suikerriet te ontwikkel, wat gebasseer is op weerstand teen die plantdoder chlorosulfuron. Suikerriet kallus was getranformeer met ‘n mutante tabak geen – asektolaktaat sintase (alsb) – wat chlorosulfuron weerstand in tabak meebring. Daar was verwag dat die geen chlorosulfuron weerstand aan transgeniese suikerriet sou oordra. Indien weerstand ontwikkel, sal die ooreenstemende suikerriet geen deur gerigte mutagenese gemuteer word; dan sal dit kan bepaal word of weerstand ook oorgedra word aan suikerriet. Daar is bevind dat alhoewel transgeniese lyne gegenereer is, daar steeds nie ‘n konklusiewe bevestiging van weerstand ontwikkeling is nie.

O uso da associação entre glifosato e atrazina para a cultura do milho geneticamente modificado tolerante ao glifosato é uma das opções de controle de plantas daninhas nesta cultura. Portanto, o objetivo principal desse trabalho foi avaliar a influência do uso desta associação em um Latossolo vermelho-escuro proveniente do bioma Cerrado do Brasil através dos ensaios de degradação e mineralização desses herbicidas, carbono da biomassa microbiana e carbono mineralizado pelo solo. Os tratamentos para os ensaios de mineralização e degradação constaram da combinação entre 14C-glifosato na dose de campo (2,88Kg ha-1) a 0, 1/2, 1 e 2 vezes a dose de campo de atrazina (3,00Kg ha-1) e 14C-atrazina na dose de campo a 0, 1/2, 1 e 2 vezes a dose de campo de glifosato. A mineralização dos herbicidas foi medida aos 0, 3, 7, 14, 21, 28, 35, 42, 49, 56 e 63 dias e a degradação aos 0, 7, 28 e 63 dias após o início do experimento. A avaliação do carbono da biomassa microbiana foi realizada aos 21 e 63 dias após o início do ensaio e foram utilizados os mesmos tratamentos com a inclusão de uma prova em branco (solo sem herbicida). O ensaio de mineralização de carbono pelo solo foi feito através da quantificação do CO2 desprendido aos 3, 7, 14, 21, 28, 35, 42, 49, 56 e 63 dias após o início do ensaio, e também teve a inclusão de uma prova em branco. Os resultados demonstraram influência na degradação e mineralização da atrazina devido a presença do glifosato. A meia-vida de mineralização de atrazina teve uma variação de aproximadamente 100 dias quando foi comparada a aplicação individual de atrazina a associação com o dobro da dose de glifosato. A influência da atrazina na degradação e mineralização de glifosato não foi nítida. A presença de atrazina provocou queda no carbono da biomassa microbiana do solo e ocorreu um aumento na velocidade e quantidade de carbono mineralizado pelo solo. Não houve alteração no carbono da biomassa microbiana do solo e mineralização de carbono pelo solo devido a adição de glifosato. Nos tratamentos em associação, a presença do glifosato no sistema impediu a redução da biomassa microbiana devido ao efeito da atrazina. A associação entre glifosato e atrazina favoreceu a mineralização de carbono pelo solo comparada a aplicação individual de glifosato. Esses resultados demonstram a necessidade por parte da pesquisa em considerar a possibilidade de interação entre os diversos xenobióticos, o que pode alterar seus comportamentos individuais no solo. / The use of glyphosate and atrazine in association for transgenic corn tolerant to glyphosate is an option to weed control in this case. Therefore, the aim of this work was to assess the influence of this association in an Oxisoil from Brazil through the degradation, mineralization, microbial biomass and carbon mineralization of soil tests. The treatments of mineralization and degradation tests consisted of the combination between 14C-glyphosate in the field rate (2,88Kg ha-1) and 0, ½, 1 and 2 times the field rate of atrazine (3,00Kg ha-1). The mineralization of herbicides was measured at 0, 3, 7, 14, 21, 28, 35, 42, 49, 56, and 63 days and the degradation was measured at 0, 7, 28 and 63 days after the beginning of the tests. The evaluation of microbial biomass was performed at 21 and 63 days after the beginning of the test and was used the same treatments of the degradation and mineralization tests, but it was included a control (soil without application of herbicides). The test of carbon mineralization of soil was done by measuring the CO2 evolved at 0,7, 14, 21, 28, 35, 42, 49, 56 and 63 days after the beginning of the test and had the same control of the microbial biomass test. The results showed an influence on degradation and mineralization of atrazine due to the presence of glyphosate. The half-life of atrazine mineralization had a variation of about 100 days when it was compared the atrazine application alone to its association with glyphosate at double rate. The influence of atrazine in degradation and mineralization of glyphosate wasnt clear. The presence of atrazine caused decrease in the microbial biomass of soil and occurred an increase in speedy and amount of carbon mineralized by soil. No change was observed in microbial biomass and carbon mineralized by soil due to glyphosate application. In the treatments that was used the association, the presence of glyphosate in the system prevented decrease of microbial biomass due to the effect of atrazine. The association between glyphosate and atrazine favored the carbon mineralization by soil when compared to glyphosate applied alone. These results demonstrate a need to consider the possibility of interactions between several xenobiotics, wich can modify their behaviors in the soil.

Submitted by FABIANA DA SILVA FRANÇA (fabiana21franca@gmail.com) on 2018-02-01T15:49:16Z No. of bitstreams: 1 Arquivo Total.pdf: 2396297 bytes, checksum: 67ed3b1d6a12c462e89a5cafd47fe5e5 (MD5) / Made available in DSpace on 2018-02-01T15:49:16Z (GMT). No. of bitstreams: 1 Arquivo Total.pdf: 2396297 bytes, checksum: 67ed3b1d6a12c462e89a5cafd47fe5e5 (MD5) Previous issue date: 2018-08-31 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES / This dissertation presents the strategy of collective organization of Polo da Borborema, with reference to the promotion of agroecological practices. The production of the foods that are in the table of the Brazilians comes from the work of the peasants and, in the case of Polo, these foods are produced from the action of rescue and maintenance of the creole seeds, known in the state of Paraíba as “Sementes da Paixão”. Among the strategies adopted by Polo in order to guarantee food sovereignty, there is the creation of Community Seed Banks. The valorization of agrobiodiversity from the specificity of Polo da Borborema organization serves as the basis for the analysis of the worldwide diffusion of research development and use of Genetically Modified Organisms in agriculture. Currently, Brazil has the second largest area planted with seeds of this type, which encourages debate on agrobiodiversity. The objective of this research was to understand how the actions of Polo da Borborema focused on the valorization of agroecology and protection of agrobiodiversity have influenced the awareness of the women of Polo as to their role for the peasant family agriculture. The research was carried out between the years of 2015 and 2017, when fieldwork was carried out, in which the farmers and leaders of the union were interviewed, as well as participation in events, with emphasis on the " March for Women's Lives and for Agroecology. " The encouragement of the participation of women in the various activities organized by Polo has represented an important movement to raise awareness about their contribution to the production of healthy foods, the valorization of the "Sementes da Paixão", as well as in awakening to the collective struggle and organized by the construction of egalitarian gender relations. / Esta dissertação apresenta a estratégia de organização coletiva do Polo da Borborema, tendo como referência a promoção de práticas agroecológicas. A produção dos alimentos que estão na mesa dos brasileiros é proveniente do trabalho dos (as) agricultores (as) camponeses (as) e, no caso do Polo, estes alimentos são produzidos a partir da ação de resgate e manutenção das sementes crioulas, conhecidas no estado da Paraíba como “Sementes da Paixão”. Dentre as estratégias adotadas pelo Polo no intuito de se garantir soberania alimentar, está a criação dos Bancos de Sementes Comunitários. A valorização da agrobiodiversidade a partir da especificidade da organização do Polo da Borborema serve de base para a análise sobre a difusão mundial do desenvolvimento de pesquisas e uso de Organismos Geneticamente Modificados na agricultura. Atualmente, o Brasil possui a segunda maior área plantada de sementes deste tipo, o que fomenta o debate a respeito da agrobiodiversidade. O objetivo desta pesquisa foi compreender como as ações do Polo da Borborema voltadas à valorização da agroecologia e proteção da agrobiodiversidade têm influenciado na tomada de consciência das mulheres do Polo quanto ao seu papel para a agricultura familiar camponesa. A pesquisa foi desenvolvida entre os anos de 2015 e 2017, quando foram realizados trabalhos de campo, em que foram entrevistados (as) agricultores (as) e lideranças da organização sindical, além de ter ocorrido a participação em eventos, com destaque para a “Marcha pela Vida das Mulheres e pela Agroecologia”. O incentivo à participação das mulheres nas diversas atividades organizadas pelo Polo tem representado importante movimento de tomada de consciência das mesmas quanto à sua contribuição na produção de alimentos saudáveis, na valorização das “Sementes da Paixão”, bem como no despertar para a luta coletiva e organizada pela construção de relações de gênero igualitárias.

The use of genetically modified (GM) maize technology is subject to compliance with stewardship requirements and the adoption of specific management practices that promote the long-term effectiveness and environmental sustainability of the technology. For smallholders to comply with these requirements and adopt the desired management practices to ultimately benefit from the technology, they require information that creates awareness of the value of these requirements. To determine what information farmers receive about GM maize and how this information is disseminated to farmers, face to face interviews were conducted with 81 extension personnel and 210 smallhoder GM maize farmers in the Eastern Cape Province of South Africa. The effect of Bt maize introduction and management practices in smallholder maize agroecosystems in the Eastern Cape on Bt maize target [Busseola fusca (Fuller) (Lepidoptera: Noctuidae)] and non-target insect pests [Agrotis segetum (Denis & Schiffermüller) (Lepidoptera: Noctuidae), Helicoverpa armigera (Hübner) (Lepidoptera: Noctuidae)] and a snail species, [Cornu aspersum (Müller) (Gastropoda: Helicidae)] was determined through laboratory, field and cage experiments. The effect of smallhoder farmers‟ GM maize cultivation practices on the profitability of GM maize technology was also determined through on-farm trials in different localities of the Eastern Cape identified as hot-spots for stem borer and weed infestation. Results of surveys indicated that extension personnel had a low level of awareness of GM maize technology stewardship requirements. GM maize technology was also largely disseminated to smallholder farmers through non-participatory approaches and print media sourced from GM seed companies. Although farmers had a high level of contact with extension services, they lacked access to information about GM maize technology. Smallholder farmers‟ level of awareness about GM maize and compliance with the requirement for the planting of non-Bt maize refuge areas adjacent to Bt maize was also very low. While Bt maize event (MON810) commonly cultivated by smallholder farmers in the Eastern Cape Province had a variable effect on A. segetum under laboratory conditions, it had no effect on the incidence of plants damaged by A. segetum and C. aspersum under field conditions. The incidence of H. armigera damage on Bt maize plants was however significantly affected by Bt maize. Populations of B. fusca collected from smallholder maize fields in the province were observed to be still highly susceptible to Bt maize. Results of on-farm evaluation of the profitability of GM maize revealed that stem borer pressure, growing conditions, input supplies and market access affect the productivity and profitability of GM maize cultivation. Challenges within the extension and advisory services of the Eastern Cape which can militate against smallholder farmers‟ ability to benefit from GM maize technology and sustain the long-term efficacy of the technology were identified during this study. Given these challenges and the fact that the cultivation of GM maize may not be profitable under typical smallholder maize cultivation conditions and management practices, dissemination approaches that provide farmers the opportunity to evaluate GM maize technology alongside alternate technologies under their conditions, may prove beneficial.

Genetically modified (GM) or transgenic crops, now more often called ``Biotech crops{\crqq} they are commercially cultivated since 1996. And also since 1996, the first year of commercialization of biotech crops, GM potatoes were cultivated in USA, Mexico, Canada and later in South Africa, China and India. The global area of approved biotech crops in 2006 was 102 million hectares and 22 countries grew biotech crops, 11 developing countries and 11 industrial countries. The Czech Republic is on of the six EU countries where biotech crops are cultivated at present. The most compelling case for biotechnology, and more specifically biotech crops, is their capability to contribute to: increasing crop productivity and stability of productivity and production; conserving biodiversity, as a land-saving technology; the production of renewable resource based bio-fuels. This diploma paper was focused on developing of fast, precise and cheap method based on PCR to detect the presence of transgenes in potatoes {--} tubers and leaves, allows monitoring the presence of GM potatoes in market, environment, etc. and to quantify ``contamination{\crqq} of ware potatoes (tubers) with GM ones.

Made available in DSpace on 2016-02-26T14:53:12Z (GMT). No. of bitstreams: 1 CamilaMenotti.pdf: 488119 bytes, checksum: f9bc062e60f29ca4d54e972920747193 (MD5) Previous issue date: 2009-03-23 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / This work presents the faunistic comparative analyses of the species of floral visitors insects, collected by manual capture means on cotton (Gossypium hirsutum L.) crop, in two fields: the conventional non-Bt cotton crop DeltaOpal® - MDM, and the transgenic Bt-cotton crop NuOpal® Bollgard®- MDM. The experiment was carried out in the city of Maracaju, state of Mato Grosso do Sul (MS), Brazil. This research aimed to survey the composition of the floral visitors in the different cotton treatments, during the crop flowering period, to assess the impact of Bt cotton on the insect fauna of flower visitors. Thus, 1,310 floral visitors were captured, being 741 of them obtained on the Bt-cotton, and 569 on the non-Bt cotton. From those insects collected in the treatment Bt, were found some individuals belonging to the following Orders: Hymenoptera (24 species), Diptera (22 species), Coleoptera (14 species), Lepidoptera (12 species), and Dermaptera (1 species). On the other hand, on the non-Bt crop were obtained insects from four Orders, such as, Hymenoptera (32 species), Diptera (27 species), Coleoptera (15 species) and Lepidoptera (10 species). The species of insects were most abundant between 9h and 10h a.m, and there was a significant difference in the composition of species. The variance analysis showed that the number of species varied significantly during the flowering period, regardless of the cotton cultivars. The composition of the floral visitors species varied according to the period of flowering, and according to the cotton cultivar. The most common species were: Apis mellifera (Linnaeus, 1758), Cycloneda sanguinea (Linnaeus, 1763), Ichneumonidae Genus A sp., Scymnus (Scymnus) sp., Anticarsia gemmatalis (Hubner,1818), Heliothis virescens (Fabricius,1781), Pseudoplusia includens (Walker,1857), Pyralidae genus A sp., Eriopis connexa (Germar,1824), Diabrotica sp., Colaspis joliveti (Bechyné,1955), Hippodamia convergens (Guérin-Méneville,1842) and Allograpta exotica (Wiedemann,1830). / Este trabalho apresenta as análises faunísticas comparativas das espécies de insetos visitantes florais, coletadas por meio de captura manual em cultivo comercial de algodão Gossypium hirsutum L.. Os dados foram obtidos em um cultivar Convencional não-Bt DeltaOpal® - MDM, e um transgênico Bt NuOpal® Bollgard®- MDM, cultivados em Maracaju, Estado do Mato Grosso do Sul, Brasil. O objetivo da pesquisa foi verificar as diferenças na comunidade de visitantes florais entre o cultivar convencional e o transgênico durante o período de floração da cultura, para avaliar o impacto do algodão Bt sobre a fauna de insetos visitantes florais. Foram capturados 1.310 visitantes florais, 741 no algodoeiro Bt, e 569 no algodoeiro não-Bt. Dos insetos coletados no algodão Bt, foram Encontrados indivíduos pertencentes as Ordens Hymenoptera (24 espécies), Diptera (22 espécies), Coleoptera (14 espécies), Lepidoptera (12 espécies) e Dermaptera (1 espécie). No algodoeiro não-Bt, coletaram-se insetos pertencentes a Hymenoptera (32 espécies), Diptera (27 espécies), Coleoptera (15 espécies) e Lepidoptera (10 espécies). As espécies de insetos foram mais abundantes nos horários das 9h:00min e 10h:00min da manhã, havendo diferença significativa na composição de espécies. A análise de variância revelou que o número de espécies variou significativamente entre os dias de floração, mas não entre os cultivares de algodão. O número de espécies teve uma diferença significativa durante o período de floração e de acordo com o tipo de algodão. As espécies mais abundantes foram Apis mellifera (Linnaeus, 1758), Cycloneda sanguinea (Linnaeus, 1763), uma espécie de Ichneumonidae, Scymnus(Scymnus) sp., Anticarsia gemmatalis (Hübner,1818), Heliothis virescens (Fabricius,1781), Pseudoplusia includens (Walker,1857),uma espécie de Pyralidae, Eriopis connexa (Germar,1824), Diabrotica sp., Colaspis joliveti (Bèchyne,1955 ), Hippodamia convergens (Guérin-Méneville,1842) e Allograpta exotica (Wiedemann,1830)

Linhagens de camundongos selecionadas para a máxima (AIRmax) ou mínima (AIRmin) resposta inflamatória aguda diferem tanto na susceptibilidade a infecção por Salmonella entérica sorotipo Typhimurium (S. Typhimurium) e ao LPS. Diferentes frequências dos alelos do gene Nramp1, envolvido na resistência inata a infecção por S. Typhimurium, foram encontradas nas linhagens AIRmax e AIRmin. Para o estudo da interação do gene Nramp1 com os loci da inflamação, sublinhagens homozigotas para os alelos R e S deste gene foram produzidas, AIRmaxRR, AIRmaxSS, AIRminRR e AIRminSS. Os animais AIRmaxRR foram sensíveis ao LPS, enquanto que os AIRminSS foram os mais resistentes a endotoxina. Quando desafiados com LPS, os animais AIRmaxRR apresentaram maior nível sérico de citocinas inflamatórias e maior expressão gênica de Tnf, Il6 e Il1b em células de fígado e medula óssea. Os AIRminRR expressaram e produziram maiores níveis de Il10. Através da análise da expressão gênica global em células de medula óssea, os AIRminSS mostraram um número maior de genes envolvidos na resposta ao LPS. / Lines of mice genetically selected for maximal (AIRmax) and minimal (AIRmin) acute inflammatory reaction differ in susceptibility to infection with Salmonella enterica serotype Typhimurium (S. Typhimurium) and to LPS sensitivity. Different frequencies of Nramp1 alleles, involved in innate resistance to S. Typhimurium infection, were found in AIRmax and AIRmin mouse lines. To study the Nramp1 gene interaction with acute inflammatory QTL, AIRmaxRR, AIRmaxSS, AIRminRR and AIRminSS sublines were produced. AIRmaxRR were found to be extremely sensitive to LPS, while the AIRminSS were the most resistant line to endotoxin. After LPS challenged, AIRmaxRR animals showed higher levels of inflammatory cytokine sera and as well as Tnf, Il6 and IL1b gene expression intensities in liver and bone marrow cells. Il10 expression was higher in AIRminRR mice. The global gene expression analysis in bone marrow cells after LPS stimulus showed higher number of differently expressed genes in AIRminSS mice.

A presente tese investiga como o Ambiente Institucional influencia o modo de governança de direitos de propriedade e a estratégia das firmas. O estudo divide-se em duas partes. A primeira parte empreende uma investigação teórica que se constitui em três etapas. Primeiro, examina-se o modelo de direitos de propriedade de Barzel (1994, 1997, 2003). Segundo, analisa-se uma abordagem de estratégia competitiva baseada em direitos de propriedade (Property Rights Perspective; Foss e Foss, 2001). Especificamente, argumenta-se que tal abordagem representa uma extensão do modelo de Barzel e demonstra-se que os conceitos introduzidos na etapa anterior possibilitam uma formulação mais geral da Property Rights Perspective, conduzindo a uma definição de estratégia competitiva que concilia as noções de strategizing e economizing (Williamson, 1991). A terceira etapa, por fim, examina particularmente o estabelecimento de estratégias de proteção de direitos de propriedade. Um modelo heurístico baseado em Williamson (1996) é proposto e com base nele três formas básicas de proteção são definidas em função da qualidade do Ambiente Institucional: estratégia centrada no sistema legal, no estabelecimento de mecanismos privados e no abandono de atributos valiosos. A segunda parte da pesquisa busca evidências empíricas que suportem o modelo teórico. O estudo examina três casos de proteção de direitos de propriedade sobre a tecnologia transgênica em sementes de soja: EUA, Brasil e Argentina. Cada um dos casos representa, respectivamente, uma forma de proteção de direitos como definido pelo modelo heurístico. A pesquisa examina também evidências econométricas que consolidam a análise empírica. De forma geral, o presente estudo desenvolve uma abordagem para o exame da apropriação de valor, colocando-se na interface entre a Economia de Direitos de Propriedade, o estudo da Estratégia e a análise do Ambiente Institucional. / The current thesis investigates how the Institutional Environment influences the mode of governance of property rights and the strategy of firms. The study is divided into two parts. The first part undertakes a theoretical investigation consisting of three steps. In the first step, the author examines the model of property rights developed by Barzel (1994, 1997, 2003). In the second step, an approach to competitive strategy based on property rights (Property Rights Perspective, Foss and Foss, 2001) is analyzed. Specifically, the author states that this approach represents an extension of Barzels model and demonstrates that the concepts introduced in the previous step allow a more general formulation of the Property Rights Perspective, leading to a definition of competitive strategy that reconciles the notions of strategizing and economizing (Williamson, 1991). The last step examines particularly the establishment of strategies for protection of property rights. A heuristic model based on Williamson (1996) is proposed and three strategies for protection of property rights are defined in terms of the quality of the Institutional Environment: strategy based on the legal system, on the establishment of private mechanisms, and on the abandon of valuable attributes. The second part of the research seeks empirical evidence to support the theoretical model. The study examines three cases of protection of property rights on genetically modified (GM) technology in soybean seeds: the US, Brazil, and Argentina. Each case represents, respectively, a strategy as defined by the heuristic model. The research also examines econometric evidence that consolidate the empirical analysis. Overall, the current study develops an approach for examining the appropriation of value, placing itself in the interface between the Property Rights Economics, the study of Strategy, and the assessment of the Institutional Environment.