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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.
41

Valuing wild pollinators for sustainable crop production

Ellis, Ciaran R. January 2014 (has links)
This thesis looks at the role of wild pollinators in providing services to crops. Two data chapters (2 and 3) are accompanied by a modelling chapter (4) which build on the findings of the field studies. The thesis ends with an overview of the trends in pollinator populations and how these relate to the needs of farmers in the UK (chap-ter 5). It is often assumed that commercial pollinators are appropriate substitutes of wild pollinators on farms; however this view neglects the differing roles that particular pollinator taxa might play in providing pollination services. For example, crops with a long growing system may require multiple pollinators to ensure pollination throughout the season. Strawberries in Scotland have an extremely long growing season, flowering from April to August. Chapter 2 presents a study showing season-al complementarity between different pollinating taxa across strawberry farms in Scotland. Pollinators of strawberries also differed in their responses to weather pa-rameters indicating that preserving multiple pollinator taxa could ensure yields un-der different weather scenarios. The requirements of a long-growing season and ad-verse weather may be specific to strawberry production in Scotland, but the valua-tion of multiple taxa can be generalised to systems with differing needs, and also to different ecosystem services. Wild bees are not only valuable for providing complementary services to commercial pollinators, but are also valuable in the longer term as it is unknown whether com-mercial pollinators will be available in the future. There are threats to the supply of honeybees which have already triggered price rises; such supply shocks could force farmers to leave production or to seek other ways of providing pollination, including supporting wild pollinators. However farm management pressures, in particular pes-ticide use, could threaten the ability of wild pollinators to continue to support crop production. The interplay of pesticides and pollination is discussed in chapter 3 and 4. Chapter 3 presents an experiment undertaken on soft-fruit farms which had and had not used the neonicotinoid, thiacloprid, and shows that nests exposed to thia-cloprid had higher worker mortality, and lower male production than those at con-trol farms. This has implications both for pollination services now, as worker mor-tality will reduce the number of bees visiting farms, and also for the maintenance of future pollination services through decreased reproductive capacity of exposed nests. Chapter 4 uses a theoretical model to link pesticide use and habitat use to pollina-tion services, and shows that the use of commercial pollinators could mask the de-cline in wild populations, making local extinctions more likely. Chapter 5 sets out the status and extent of pollinators in the UK, along with popu-lation trends, trends in habitat and trends in pesticide use to provide an overview of how well pollination services are likely to meet the ongoing needs of crop farmers.
42

Genetic parameters for morphometric traits of africanized honeybee drones / Parâmetros genéticos para características morfométricas de zangões africanizados

Rodrigues, Marisa Clemente 31 August 2016 (has links)
Estudos sobre estimação de parâmetros genéticos em abelhas, com foco em abelhas africanizadas e na casta masculina da espécie, são escassos. O objetivo desse estudo foi estimar correlações genéticas para peso e características morfométricas de zangões à emergência e maturidade, para que em futuros programas de melhoramento essas características possam servir como critérios de seleção. Foram estimados parâmetros fenotípicos e genéticos para peso (W), comprimento total (TL), comprimento do abdômen (AL), largura do abdome (AW), comprimento da asa (WL) e largura da asa (WW) de zangões à emergência (E ) e maturidade (M) recorrendo a modelos de análise uni e bicaracter. Os parâmetros genéticos como variância genética, herdabilidade e correlações genéticas foram estimadas por meio do procedimento Bayesiano usando amostragem de Gibbs. Resultados: Foram medidos 1117 zangões à emergência e 336 novamente à maturidade. De acordo com a análise unicaracter, as herdabilidades foram 0.78, 0.52, 0.56, 0.93 e 0.92 para WE, WM, ALM, WLM e WWM, respectivamente. A correlação genética entre WE e as restantes características variou entre 0.55 e 0.83. Conclusões: As características W E, WM, TLM, ALM, WLM, WWM, quando consideradas individualmente, podem ser usadas como critério de seleção porque a variância genética aditiva para essas características foi responsável por mais de 50% da variação fenotípica total. O W E pode ser usado como critério de seleção se se ambicionar o melhoramento das restantes características à emergência. Os parâmetros genéticos obtidos para peso, comprimento total e comprimento do abdome à emergência indicam que há potencial de ganho genético para as características morfométricas à maturidade. Esses critérios podem embasar o estudo genético quantitativo das características morfométricas e reprodutivas à maturidade, que são de difícil mensuração. / Available information on Africanized honeybee breeding, especially regarding the male component of the species, is almost non-existent. The aim of this study was to estimate genetic correlations for weight and morphometric traits of drones at emergence and maturity, so that in future breeding programs these traits can act as selection criteria through their genetic value. Phenotypic and genetic parameters were estimated for weight and morphometric traits such as weight (W), total length (TL), abdomen length (AL), abdomen width (AW), wing length (WL) and wing width (WW) at drones’ emergence (E) and maturity (M). Single-trait and two-trait models were used and parameters such as genetic variance, heritability and genetic correlations were calculated using a Bayesian approach. Results: A total of 1117 drones were measured at emergence and 336 again at maturity. In single-trait models, heritabilities were 0.78, 0.52, 0.56, 0.93 and 0.92 for WE, WM, ALM, WL M and WWM, respectively. The genetic correlation between WE and the remaining traits ranged from 0.55 to 0.83. Conclusions: Traits such as W E, WM, TLM, ALM, WLM, WWM, when considered individually, can be used as selection criteria because genetic variance for these traits accounted for more than 50% of the total phenotypic variance. The WE combined with other traits assessed at drones' emergence can be used in breeding programs for the improvement of the aforementioned traits. Breeding selection for weight or total length at emergence promises considerable genetic progress for weight at maturity. The combination of genetic parameters for reproductive and morphometric traits in drones properly supported by breeding programs relying on artificial insemination, for an effective mating control, will likely help in clarifying this possibility.
43

Genetic parameters for morphometric traits of africanized honeybee drones / Parâmetros genéticos para características morfométricas de zangões africanizados

Rodrigues, Marisa Clemente 31 August 2016 (has links)
Estudos sobre estimação de parâmetros genéticos em abelhas, com foco em abelhas africanizadas e na casta masculina da espécie, são escassos. O objetivo desse estudo foi estimar correlações genéticas para peso e características morfométricas de zangões à emergência e maturidade, para que em futuros programas de melhoramento essas características possam servir como critérios de seleção. Foram estimados parâmetros fenotípicos e genéticos para peso (W), comprimento total (TL), comprimento do abdômen (AL), largura do abdome (AW), comprimento da asa (WL) e largura da asa (WW) de zangões à emergência (E ) e maturidade (M) recorrendo a modelos de análise uni e bicaracter. Os parâmetros genéticos como variância genética, herdabilidade e correlações genéticas foram estimadas por meio do procedimento Bayesiano usando amostragem de Gibbs. Resultados: Foram medidos 1117 zangões à emergência e 336 novamente à maturidade. De acordo com a análise unicaracter, as herdabilidades foram 0.78, 0.52, 0.56, 0.93 e 0.92 para WE, WM, ALM, WLM e WWM, respectivamente. A correlação genética entre WE e as restantes características variou entre 0.55 e 0.83. Conclusões: As características W E, WM, TLM, ALM, WLM, WWM, quando consideradas individualmente, podem ser usadas como critério de seleção porque a variância genética aditiva para essas características foi responsável por mais de 50% da variação fenotípica total. O W E pode ser usado como critério de seleção se se ambicionar o melhoramento das restantes características à emergência. Os parâmetros genéticos obtidos para peso, comprimento total e comprimento do abdome à emergência indicam que há potencial de ganho genético para as características morfométricas à maturidade. Esses critérios podem embasar o estudo genético quantitativo das características morfométricas e reprodutivas à maturidade, que são de difícil mensuração. / Available information on Africanized honeybee breeding, especially regarding the male component of the species, is almost non-existent. The aim of this study was to estimate genetic correlations for weight and morphometric traits of drones at emergence and maturity, so that in future breeding programs these traits can act as selection criteria through their genetic value. Phenotypic and genetic parameters were estimated for weight and morphometric traits such as weight (W), total length (TL), abdomen length (AL), abdomen width (AW), wing length (WL) and wing width (WW) at drones’ emergence (E) and maturity (M). Single-trait and two-trait models were used and parameters such as genetic variance, heritability and genetic correlations were calculated using a Bayesian approach. Results: A total of 1117 drones were measured at emergence and 336 again at maturity. In single-trait models, heritabilities were 0.78, 0.52, 0.56, 0.93 and 0.92 for WE, WM, ALM, WL M and WWM, respectively. The genetic correlation between WE and the remaining traits ranged from 0.55 to 0.83. Conclusions: Traits such as W E, WM, TLM, ALM, WLM, WWM, when considered individually, can be used as selection criteria because genetic variance for these traits accounted for more than 50% of the total phenotypic variance. The WE combined with other traits assessed at drones' emergence can be used in breeding programs for the improvement of the aforementioned traits. Breeding selection for weight or total length at emergence promises considerable genetic progress for weight at maturity. The combination of genetic parameters for reproductive and morphometric traits in drones properly supported by breeding programs relying on artificial insemination, for an effective mating control, will likely help in clarifying this possibility.
44

Redes geográficas e potencial fitogeográfico apícola nos territórios produtivos de Sergipe

Silva, Edimilson Gomes 31 October 2013 (has links)
This work analyzes the geographical networks and the phytogeographical potential for beekeeping in Sergipe the light of geographical networks as a category of analysis, with the empirical cut territories planning: the High Wilderness, with highlights for municipalities Canindé de São Francisco, Poço Redondo, Porto da Folha, Nossa Senhora da Glória e Nossa Senhora de Lourdes; Agreste Central (Frei Paulo); Sul Sergipano (Estancia and Salgado); Centro Sul (Lagarto, Poço Verde and Tobias Barreto); and, Baixo São Francisco (Brejo Grande). The research took place from bibliographic, documental and census on the theme addressed; fieldwork from visits to productive territories that have phytogeographical potential for beekeeping; semi-structured interviews with the actors who are part of the network and beekeeping with representatives warehousing and cooperatives beekeepers, application of cartographic techniques for the preparation of maps, land and tabulation, and analysis and interpretation of information. The geographical networks of beekeeping are configured in networks of production, marketing, financial, technical, scientific and informational whose analysis reveals the existence of phytogeographical potential in forest remnants able to meet the practice and development of beekeeping in Sergipe. However, besides the weather, the factors of structural and organizational hamper the growth of this activity: the lack of synergy between actors constituents of the network, the lack of professionalism on the part of beekeepers, though they have technical knowledge, still practice activity amateur way, and insufficient processing units (House of Honey) built based technical standards set by government agencies, among others. To target the growth and strengthening of beekeeping are needed structural improvements, such as: scientific-technical support, financial and informational effective government bodies; structuring and creation of units of extraction and processing of bee products; structuring and organization of beekeepers´ associations and their inclusion in the Federation of beekeepers of Sergipe; strengthening commercialization via creation of warehousing in Sergipe, providing areas for Community production in areas with phytogeographical potential initiated by the government (federal, state and local), creation of partnerships between landowners and beekeepers via government agencies offering benefits to the owners , and , after the effective structuring of geographical networks, enabling the creation of a Technological Center beekeeping in partnership with the State of Bahia to meet the interior of Bahia and Sergipe since the geographical networks beekeeping sergipana beyond its boundaries in search of phytogeographical potential. These strategies provide the desired consolidation of Local Productive Arrangement (APL) in the context of state and Local Territorial System (SLOT) locally. / Esse trabalho visa analisar as redes geográficas e o potencial fitogeográfico para atividade apícola em Sergipe à luz das redes geográficas enquanto categoria de análise, tendo como recorte empírico os territórios de planejamento: o Alto Sertão, com destaques para os municípios de Canindé de São Francisco, Poço Redondo, Porto da Folha, Nossa Senhora da Glória e Nossa Senhora de Lourdes; Agreste Central (Frei Paulo); Sul Sergipano (Estância e Salgado); Centro Sul (Lagarto, Poço Verde e Tobias Barreto); e, Baixo São Francisco (Brejo Grande). A pesquisa ocorreu a partir de levantamento bibliográfico, documental e censitário acerca da temática abordada; pesquisa de campo a partir de visitas aos territórios produtivos que dispõe de potencial fitogeográfico para a apicultura; entrevistas semiestruturadas com os atores que fazem parte da rede apícola e com representantes de entrepostos e cooperativas de apicultores; aplicação de técnicas cartográficas para elaboração dos mapas; ordenamento e tabulação dos dados; e, análise e interpretação das informações. As redes geográficas da apicultura encontram-se configurada em redes de produção, de comercialização, financeira, técnica, científica, e informacional cujas análises evidenciam a existência de potencial fitogeográfico nos remanescentes florestais capazes de atender a prática e o desenvolvimento da apicultura em Sergipe. Entretanto, além das condições climáticas, os fatores de caráter estrutural e organizacional dificultam o crescimento dessa atividade: a falta de sinergia entre atores constituintes da rede; a inexistência de profissionalismo por parte dos apicultores, que embora tenham conhecimentos técnicos, ainda praticam a atividade de forma amadora; e quantidade insuficiente de unidades de beneficiamento (Casa do Mel) edificadas com base nas normas técnicas estabelecidas pelos órgãos governamentais, dentre outros. Para almejar o crescimento e fortalecimento da apicultura são necessárias melhorias estruturais, como: apoio técnico-científico, informacional e financeiro efetivos pelos órgãos governamentais; estruturação e criação de unidades de extração e beneficiamento dos produtos apícolas; estruturação e organização das associações de apicultores e sua inclusão na Federação de Apicultores de Sergipe; fortalecimento da comercialização via criação de entreposto em Sergipe; disponibilização de áreas para produção comunitária nos territórios com potencial fitogeográfico por iniciativa do governo (federal, estadual e local); realização de parcerias entre proprietários de terras e apicultores via órgãos governamentais oferecendo benefícios aos proprietários; e, após a estruturação efetiva das redes geográficas, viabilizar a criação de um Centro Tecnológico da Apicultura em parceria com o Estado da Bahia visando atender o sertão sergipano e baiano já que as redes geográficas da apicultura sergipana ultrapassam seus limites territoriais em busca de potencial fitogeográfico. Essas estratégias proporcionarão a consolidação do almejado Arranjo Produtivo Local (APL) no contexto estadual e do Sistema Local Territorial (SLOT) no âmbito local.

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