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| Registros recuperados: 150 | |
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| Madanes,Nora; Fernández,Celina A. |
| The aim of this study is to analyze factors and mechanisms involved in dispersal and deposition of airborne pollen captured with Tauber type traps in a 20 x 20 m plot of Helianthus annus cultivation and accompanying weeds and to investigate the relation of these processes with the vegetation structure and dynamics from cultivation to its senescence over a 14 week period. Weekly samples obtained with pollen traps showed a significant change in the deposition due to a filter effect and dispersal patterns due to source variations during the time elapsed. A conceptual and interpretative model for both processes and its relation to pollen sources is proposed. Our results showed that in the study site, the leaves development of Helianthus annus produced a pollen... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Airborne pollen; Phenology; Helianthus annus; Weeds. |
| Ano: 2018 |
URL: http://www.scielo.org.ar/scielo.php?script=sci_arttext&pid=S0011-67932018000100003 |
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| Hernández Flores, Benjamín. |
| El tomate es una de las especies vegetales más importantes en el mundo. La producción de este cultivo es considerada como una actividad de alto riesgo debido a su gran susceptibilidad a plagas que limitan su producción. En años recientes, se observaron síntomas de detención general del crecimiento, clorosis, deformación foliar, abscisión de flores y reducción de tamaño y cantidad de frutos, característicos de infección por begomovirus y Candidatus Liberibacter psyllaurous en plantas de tomate cultivadas en invernadero en los estados de Coahuila, Puebla e Hidalgo. Con la finalidad de determinar la presencia de estos patógenos se colectó tejido foliar de plantas de tomate y de malezas que mostraban los síntomas antes descritos. Se realizó la extracción de... |
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Palavras-chave: Mosca blanca; Geminivirus; Malezas; Bactericera cockerelli; Análisis temporal; Whiteflies; Weeds; Temporal analysis; Fitopatología; Doctorado. |
| Ano: 2013 |
URL: http://hdl.handle.net/10521/1884 |
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| Guillermo Gómez, María Asunción. |
| Los potreros están cubriendo una proporción cada vez más grande del trópico húmedo de México, mientras el área de selvas y del cultivo de maíz ha ido en descenso. Pero, existe muy poca información sobre la composición florística y ecológica de estos pastizales inducidos. En este trabajo se compara la florística, fitogeografía, diversidad, etnobotánica y usos de la vegetación en milpas y potreros en el municipio de Candelaria, Campeche, entre la población de la etnia chol; además de que se describe el manejo de cada tipo de vegetación (milpa/potrero) con detalle. Se parte de la premisa que las milpas tendrán mayor diversidad, una proporción más grande de especies nativas y útiles, y que son recolectadas en cantidades mayores que los potreros, por ser el... |
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Palavras-chave: Arvense; Diversidad; Cobertura; Frecuencia; Aprovechamientos; Weeds; Diversity; Coverage; Frequency; Uses; Botánica; Maestría. |
| Ano: 2013 |
URL: http://hdl.handle.net/10521/2091 |
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| Manduna, Idah Tichaidza. |
| La recolección de plantas comestibles es un componente importante en sistemas de agricultura tradicional. Estas plantas forman parte de las dietas locales. El objetivo de esta investigación fue comparar el conocimiento y uso de plantas comestibles recolectadas que complementan la dieta basada en maíz en comunidades rurales, con el fin de identificar patrones generales en dos poblaciones con condiciones similares, pero sin contactos directos en el pasado. Se recopiló información en Santa Catarina Roatina y Villa Talea de Castro de Oaxaca, México y Chipupuri y Maradzika de Honde Valley, Zimbabwe mediante entrevistas grupales e individuales, diarios de alimentos y observación participante. También se muestrearon los arvenses de cultivos de maíz para... |
| Tipo: Tesis |
Palavras-chave: Conocimiento etnobotánico; Arvenses; Origen biogeográfica; Doctorado; Botánica; Doctorado; Botánica; Ethnobotanical knowledge; Weeds; Biogeographical origins. |
| Ano: 2008 |
URL: http://hdl.handle.net/10521/1521 |
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| Ngobo, Martine; IITA; m.ngobo@cgiar.org; McDonald, Morag; University of Wales, Bangor; mamcd@bangor.ac.uk; Weise, Stephan; ; s.weise@cgiar.org. |
| In the humid forest regions of southern Cameroon in central Africa, sectoral and macroeconomic policy reforms introduced in the late 1980s have led to intensified land use, which in turn has resulted in, among other environmental consequences, shortened fallow systems dominated by the Asteraceae shrub, Chromolaena odorata (L.) King and Robinson, rather than by secondary forest species. A trial was established to determine the effect of shortened fallow duration and invasion by C. odorata on the weed flora in subsequent mixed food cropping systems. Plots were established in cleared 5- to 7-year-old fallow fields in which the vegetation was either dominated by C. odorata or not, and in which the dominant fallow vegetation in the previous... |
| Tipo: Peer-Reviewed Reports |
Palavras-chave: CVA; Cameroon; Chromolaena odorata; Fallow; Weeds. |
| Ano: 2004 |
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| Blumenthal, Dana M; University of Minnesota; dblumenthal@npa.ars.usda.gov; Jordan, Nicholas R; University of Minnesota; perr0128@tc.umn.edu; Svenson, Elizabeth L; University of Minnesota; esvenso1@swarthmore.edu. |
| The potential weed control benefits of ecological restoration are rarely cited and largely unstudied. Nevertheless, the nature of many restoration target communities, i.e., diverse, late-successional communities, suggests that restoration may control weeds and that the invasibility of plant communities may decrease with both diversity and successional age. Given the high cost of weed control in nonagricultural land, weed control benefits could be a strong incentive for restoration efforts. We examined the cumulative effects of restoration on weed populations 7 yr after tallgrass prairie restoration on a Minnesota sand plain. The numbers and biomass of volunteer weeds were compared among randomized plots with (1) no restoration, (2) prairie seed addition,... |
| Tipo: Peer-Reviewed Reports |
Palavras-chave: Community invasibility; Invasion; Prairie; Restoration; Succession; Weed competition; Weed control; Weeds. |
| Ano: 2003 |
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| Guglielmini,Antonio C; Ghersa,Claudio M; Satorre,Emilio H. |
| Crops and weeds co-evolve in particular plant communities that are assembled in agro-ecosystems. In this essay we discuss the mechanisms determining this co-evolution and the processes regulating the success of individual populations within crop-weed communities as a starting point to evaluate and interpret which are the risks of promoting invasive species due to technological changes introduced into cropping activities. We follow a framework considering co-evolutionary mechanisms (namely, genetic variation, breeding system and selective forces) and demographical processes (namely, establishment, competition, dispersion) as a way to predict, not only how weeds will evolve in agricultural land, and thus how new problems for production of food and fibre... |
| Tipo: Info:eu-repo/semantics/report |
Palavras-chave: Evolutionary mechanisms; Demographical processes; Weeds; Crops. |
| Ano: 2007 |
URL: http://www.scielo.org.ar/scielo.php?script=sci_arttext&pid=S1667-782X2007000100016 |
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| OLIVEIRA, M. F. de; KARAM, D.; MATRANGOLO, W. J. R.. |
| As preocupações com a disponibilidade de alimentos em quantidade e qualidade para a população em geral têm direcionado demandas de pesquisas visando o desenvolvimento de sistemas de produção de grãos de menor impacto ambiental. Isso porque os consumidores têm se tornado mais exigentes quanto aos padrões de qualidade dos produtos e do ambiente. Adicionalmente, demandam-se métodos de produção que promovam a permanência do agricultor no campo e com redução no custo de produção. Novos nichos de mercado, mesmo que pequenos, têm surgido. A área de orgânicos no Brasil é de cerca de 750 mil hectares, contando com mais de 10 mil produtores e aproximadamente 13 mil unidades de produção, mas com grande potencial de crescimento. A produção de milho orgânico exige... |
| Tipo: Comunicado Técnico (INFOTECA-E) |
Palavras-chave: Erva daninha; Weeds. |
| Ano: 2015 |
URL: http://www.infoteca.cnptia.embrapa.br/infoteca/handle/doc/1037821 |
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| Registros recuperados: 150 | |
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