Tesis: "Potato crops"

7

Harris, P. M. "Tempering the effects of water stress in sugar beet and potato crops." Thesis, University of Reading, 1994. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.385139.

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8

Bunyolo, A. M. "Effects of fertilizer nitrogen and water supply on growth and yield of the potato crops." Thesis, University of Reading, 1987. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.379220.

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9

Lynch, Ryan P. "Controlling Soilborne Diseases of Potato and Influencing Soil Microbiology with Brassica Cover Crops." Fogler Library, University of Maine, 2008. http://www.library.umaine.edu/theses/pdf/LynchRP2008.pdf.

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10

Plotkin, Jeremy Barker. "The Effects of Green Manure Rotation Crops on Soils and Potato Yield and Quality." Fogler Library, University of Maine, 2000. http://www.library.umaine.edu/theses/pdf/PlotkinJB2000.pdf.

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11

Al-Hagdow, Moftah Moh. "Interactions between sodium and potassium in micropropagated potato cultivars differing in salinity tolerance." Thesis, McGill University, 1998. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=20554.

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The response of in vitro-grown Solanum tuberosum L., cvs. Russet Burbank (RB) (salt-sensitive) and Sierra (S) (salt-tolerant) potatoes was investigated when [NaCl] was increased from 0 to 80 mM in the presence of 6, 20, and 30 mM [K] in a Murashige and Skoog (MS) basal medium. The tested growth parameters, Mg and Ca content, and K+/Na + ratios in the laminae and the roots were negatively affected as [NaCl] increased. The salt stress was relatively severe on growth of RB plants whereas the salt-tolerant (S) variety was affected to a lesser extent. There were indications that Na in the plant may promote Na translocation. In both cultivars, 22Na was not distributed equally in all plant parts; the lower lamina accumulated the highest amount (216 and 183 DPM mg -1 FW) followed by stem (197 and 182), petioles (187 and 168), and the upper lamina (149 and 121) for RB and S, respectively. The salt resistance of S is associated not only with a superior capacity to accumulate high Na+ in the roots for osmotic adjustment, but also with resistance to Na movement to the shoot. The effect of [K] on plant growth showed two main characteristics. In non-saline media, increasing [K] enhanced growth of S, while RB showed optimum growth when the normal (20 mM) level was present in the MS medium. In saline media, elevating [K] alleviated the growth reduction of RB at low salinity, and S at both low and high salinity. This ameliorative effect of K may be attributed to the suppression of both Na+ uptake, and Na + translocation in the plant.

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12

Zhang, Yanling 1955. "Development of in vitro bioassays for determination of salinity tolerance in potato (Solanum spp.)." Thesis, McGill University, 1998. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=35659.

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Salinity problems seriously affect agricultural production by reducing crop yield and arable land. The evaluation of potato genotypes (Solanum spp.) for their salinity (NaCl) tolerance in conventional field trials is time consuming and labour intensive. The results are often confounded by many field and environmental variations. In vitro bioassays can overcome some of these difficulties by providing faster, more convenient and dependable methods for screening and selection of salt tolerant potato genotypes. The objective of this research was to develop in vitro bioassay methods for screening and selection of salt tolerant potato. Under in vitro NaCl stress conditions, seed germination, early seedling growth, and single-node cutting bioassays were used to evaluate salinity tolerance. The selected genotypes were further tested with three in vitro bioassays (single-node cuttings, root tip segments, and microtuberization). The rankings of potato cultivar salinity tolerance were similar in these bioassays. The single-node cutting bioassay was recommended because it was simpler to perform than the root tip segment and microtuberization bioassays and did not exclude certain genotypes as did the microtuberization bioassay. The in vitro bioassay rankings were compared with yield ranking in field lysimeters. In both the in vitro and in vivo saline stress experiments, cvs. Kennebec and Russet Burbank were more salt tolerant than Norland. The tubers and microtubers harvested from previous experiments were tested in the greenhouse to investigate salinity carry-over effect for seed tuber production. There was no apparent residual carry-over effect found. Microtuber yield increase in the presence of low NaCl concentration was induced primarily by specific ion (Na+), and not osmotic effects. This research clearly indicated that in vitro bioassays are relatively simple, rapid, convenient, repeatable, and agree with the field lysimeter results. They can be used to substitute for f

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13

Ragsdale, Jeanna D. "Influence of cover crops on nutrient availability in a sweet potato cropping system in south Florida." [Gainesville, Fla.] : University of Florida, 2006. http://purl.fcla.edu/fcla/etd/UFE0015300.

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14

Haverkort, A. J. "Relationships between intercepted radiation and yield of potato crops under tropical highland conditions of Central Africa." Thesis, University of Reading, 1985. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.370132.

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15

NDAYISENGA, VALENCE. "APPROPRIATE FOOD PRODUCTION THROUGH INCREASING CROP YIELD AND INTRODUCING NEW CROPS IN THE DEMOCRATIC REPUBLIC OF THE CONGO." Doctoral thesis, Università Cattolica del Sacro Cuore, 2018. http://hdl.handle.net/10280/53793.

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La mancanza di una buona dieta ben bilanciata nutrizionalmente, porta al persistente sottosviluppo, in particolare per la capacità fisica e intellettuale delle persone e ha un impatto negativo sullo sviluppo del Paese. La presente tesi di dottorato mirava a valutare le strategie per produrre un cibo appropriato sufficiente, sicuro e sostenibile attraverso la sperimentazione di diverse tecniche di coltivazione e cultivar locali di manioca per identificare quali tecniche e cultivar sono più performanti per aumentare la resa. Dall’altra parte, al fine di contribuire alla diversificazione della produzione del cibo e al miglioramento del piatto tradizionale congolese costituita da più di 80% di carboidrati in particolare la manioca, studi su nuove colture riconosciute contenere dei buoni livelli in proteine, vitamine e minerali come Patata dolce a polpa arancione (Ipomoea batatas) riconosciuta essere ricca soprattutto in provitamina A e quinoa (Chenopodium quinoa Willd.) riconosciuta in particolare per il suo buon contenuto di aminoacidi ben bilanciato sono state condotte. Come risultato, tra tre tecniche di coltivazione (Ridge, Mound e Flat) per la produzione di manioca e 5 cultivar locali di manioca (Dunda, Kakuanga, Kasongoy, Kasonie, Ngoymuamba) valutati, la coltivazione su Ridge e il culltivar Ngoymuamba hanno dato il risultato più alto (19,2 Mg ha-1 di tuberi freschi), mentre Dunda è stata la cultivar che ha prodotto molto meno (6,8 Mg ha-1 di tuberi freschi). Le cultivar di patata dolce a polpa arancione studiati, hanno dimostrato che il contenuto in β-carotene è ragionevolmente alto perché 87 g di tuberi fresche sono sufficienti per coprire la dose giornaliera raccomandata in vitamina A per gli adulti. Per quinoa, tre cultivar (Pasankalla, Puno, Titicaca) hanno dimostrato di produrre una resa considerevole in quanto la produzione in granella è stata rispettivamente di 2,2 Mg ha-1; 1,9 Mg ha-1; 1,3 Mg ha-1 per Titicaca, Pasankalla e Puno. The lack of a good diet well balanced nutritionally, leads to the persistent underdevelopment, particularly for the physical and intellectual capacity of the people and impacts negatively on the development of the country. The present doctoral thesis aimed to assess strategies to produce an appropriate food sufficient, safe and sustainable through experimenting different cultivating techniques and local cultivars of cassava for identifying which techniques and cultivars are more performant to increase yield. On the other hand, in order to contribute to the diversification of food production and improvement of the traditional Congolese diet constituted by more than 80% of carbohydrates particularly cassava, new crops recognized to have a better content in protein, minerals, and vitamins such as Orange-Fleshed Sweet Potato (Ipomoea batatas) recognized to be rich especially in provitamin A and quinoa (Chenopodium quinoa Willd.) recognized particularly for its well-balanced amino acids content were studied. As results, among three Planting methods (Ridge, Mound, and Flat) for producing cassava and 5 local cultivars of cassava (Dunda, Kakuanga, Kasongoy, Kasonie, Ngoymuamba) assessed, ridge and culltivar Ngoymuamba resulted to give the highest yield (19.2 Mg ha-1 in fresh roots), while Dunda was the cultivar which produced the lowest yield (6.8 Mg ha-1 in fresh roots). The Orange-Fleshed Sweet Potato cultivars studied showed that its content in β-carotene is reasonably high as 87 g per day can cover the whole daily allowances of vitamin A in adults’ people. On the quinoa side, three cultivars (Pasankalla, Puno, Titicaca) demonstrated to produce considerable yield as the production in grain was 2.2 Mg ha-1, 1.9 Mg ha-1, 1.3 Mg ha-1, respectively for Titicaca, Pasankalla and Puno.

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16

NDAYISENGA, VALENCE. "APPROPRIATE FOOD PRODUCTION THROUGH INCREASING CROP YIELD AND INTRODUCING NEW CROPS IN THE DEMOCRATIC REPUBLIC OF THE CONGO." Doctoral thesis, Università Cattolica del Sacro Cuore, 2018. http://hdl.handle.net/10280/53793.

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La mancanza di una buona dieta ben bilanciata nutrizionalmente, porta al persistente sottosviluppo, in particolare per la capacità fisica e intellettuale delle persone e ha un impatto negativo sullo sviluppo del Paese. La presente tesi di dottorato mirava a valutare le strategie per produrre un cibo appropriato sufficiente, sicuro e sostenibile attraverso la sperimentazione di diverse tecniche di coltivazione e cultivar locali di manioca per identificare quali tecniche e cultivar sono più performanti per aumentare la resa. Dall’altra parte, al fine di contribuire alla diversificazione della produzione del cibo e al miglioramento del piatto tradizionale congolese costituita da più di 80% di carboidrati in particolare la manioca, studi su nuove colture riconosciute contenere dei buoni livelli in proteine, vitamine e minerali come Patata dolce a polpa arancione (Ipomoea batatas) riconosciuta essere ricca soprattutto in provitamina A e quinoa (Chenopodium quinoa Willd.) riconosciuta in particolare per il suo buon contenuto di aminoacidi ben bilanciato sono state condotte. Come risultato, tra tre tecniche di coltivazione (Ridge, Mound e Flat) per la produzione di manioca e 5 cultivar locali di manioca (Dunda, Kakuanga, Kasongoy, Kasonie, Ngoymuamba) valutati, la coltivazione su Ridge e il culltivar Ngoymuamba hanno dato il risultato più alto (19,2 Mg ha-1 di tuberi freschi), mentre Dunda è stata la cultivar che ha prodotto molto meno (6,8 Mg ha-1 di tuberi freschi). Le cultivar di patata dolce a polpa arancione studiati, hanno dimostrato che il contenuto in β-carotene è ragionevolmente alto perché 87 g di tuberi fresche sono sufficienti per coprire la dose giornaliera raccomandata in vitamina A per gli adulti. Per quinoa, tre cultivar (Pasankalla, Puno, Titicaca) hanno dimostrato di produrre una resa considerevole in quanto la produzione in granella è stata rispettivamente di 2,2 Mg ha-1; 1,9 Mg ha-1; 1,3 Mg ha-1 per Titicaca, Pasankalla e Puno. The lack of a good diet well balanced nutritionally, leads to the persistent underdevelopment, particularly for the physical and intellectual capacity of the people and impacts negatively on the development of the country. The present doctoral thesis aimed to assess strategies to produce an appropriate food sufficient, safe and sustainable through experimenting different cultivating techniques and local cultivars of cassava for identifying which techniques and cultivars are more performant to increase yield. On the other hand, in order to contribute to the diversification of food production and improvement of the traditional Congolese diet constituted by more than 80% of carbohydrates particularly cassava, new crops recognized to have a better content in protein, minerals, and vitamins such as Orange-Fleshed Sweet Potato (Ipomoea batatas) recognized to be rich especially in provitamin A and quinoa (Chenopodium quinoa Willd.) recognized particularly for its well-balanced amino acids content were studied. As results, among three Planting methods (Ridge, Mound, and Flat) for producing cassava and 5 local cultivars of cassava (Dunda, Kakuanga, Kasongoy, Kasonie, Ngoymuamba) assessed, ridge and culltivar Ngoymuamba resulted to give the highest yield (19.2 Mg ha-1 in fresh roots), while Dunda was the cultivar which produced the lowest yield (6.8 Mg ha-1 in fresh roots). The Orange-Fleshed Sweet Potato cultivars studied showed that its content in β-carotene is reasonably high as 87 g per day can cover the whole daily allowances of vitamin A in adults’ people. On the quinoa side, three cultivars (Pasankalla, Puno, Titicaca) demonstrated to produce considerable yield as the production in grain was 2.2 Mg ha-1, 1.9 Mg ha-1, 1.3 Mg ha-1, respectively for Titicaca, Pasankalla and Puno.

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17

Stevens, Paul Thomas. "Nitrogen Management and the Effects of Compost Tea on Organic Irish Potato and Sweet Corn." Thesis, Virginia Tech, 2008. http://hdl.handle.net/10919/33418.

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Supply and synchronization of plant-available nitrogen (N) to the soil is a major challenge for organic farmers, especially when growing crops in soils that are in transition from conventional to organic systems. This research evaluated the effects of site produced cover crops and application of soil amendments on N uptake and crop yield of organic Irish potato (Solanum tuberosum) and sweet corn (Zea mays). Cover crops were crimson clover (Trifolium incarnatum) and forage radish (Raphanus sativus). Soil amendments included in-row application of commercially produced dehydrated compost tea absorbed on charcoal (Soil Biology Innovations) and post-plant sidedressing with organic N fertilizer. Irish potato and sweet corn were grown at the Kentland Agricultural Research Farm near Blacksburg, VA in an organic transition soil during the summers of 2006 and 2007. Nitrogen uptake and crop yield were not affected by cover crop species in either year. SBI increased yield of sweet corn, but not Irish potato for both years; SBI had no effect on N uptake of either crop. Post-plant N sidedressing increased N uptake and crop yield of Irish potato and sweet corn in 2007, but had no effect on crop yield in 2006, presumably because pre-plant organic fertilizer was applied at planting in 2006, but not in 2007. This study shows that the combination of site produced cover crops and applied soil amendments may be required to produce high marketable yields of organic Irish potato and sweet corn in the transition soil used in these experiments. Master of Science

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18

Cabrera, Lilian Cervo. "Cooperation in science : the role of scientific collaboration in the study of diseases in wheat and potato crops." reponame:Biblioteca Digital de Teses e Dissertações da UFRGS, 2017. http://hdl.handle.net/10183/164382.

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As doenças em plantas podem causar grandes perdas e representar um risco real para a segurança alimentar mundial. Para enfrentar esse desafio, a cooperação entre stakeholders do agronegócio é fundamental. Sendo assim, esta tese tem como proposta mensurar e analisar o papel da cooperação – colaboração científica – no manejo de doenças em plantas, especialmente no trigo e na batata. Para tanto, são apresentados três estudos que abordam tal temática. O primeiro estudo se propõe a caracterizar e estudar o funcionamento de algumas redes de pesquisa agrícola que monitoram patógenos, desenvolvem e distribuem cultivares resistentes a doenças e sequenciam o genoma do trigo e da batata. Nele, discute-se também como alguns patógenos podem ameaçar a estabilidade da produção de trigo e batata no mundo, especialmente o fungo Puccinia graminis f. sp. tritici, causador da ferrugem-do-colmo no trigo e o oomiceto Phytophthora infestans, causador da requeima na batata. Diferentes instituições como consórcios, centros de pesquisa e instituições estabelecidas são consideradas para ilustrar seu envolvimento em redes e para discutir suas atividades. O segundo artigo busca mensurar a colaboração científica nas publicações disponíveis na Web of Science por meio da análise de coautoria. O objetivo foi mapear os países que colaboram cientificamente na área de segurança alimentar. Foram considerados artigos publicados no período de 1996 a 2016 e os resultados analisados com o software VOSviewer. O terceiro artigo busca mapear os intercâmbios de germoplasma realizados pelos programas de melhoramento de batata no mundo para medir a colaboração entre países. Neste artigo, foram utilizadas informações somente sobre a batata. Cultivares de batata resistentes à requeima foram selecionadas com base em duas bases de dados, uma europeia – European Cultivated Potato Database (ECPD) - e outra brasileira - Catálogo de Cultivares da Batata da Embrapa 2015. A construção dos mapas, dos gráficos e os procedimentos de cálculo foram feitos no Microsoft Excel, no Tableau 10.1 e com o software RTBMaps. O Cosseno de Salton foi utilizado para normalização dos dados. Os resultados sugerem que pesquisa colaborativa conduzida pelas redes traz mais benefícios do que a pesquisa individual ao evitar a sobreposição de estudos, economizar tempo e recursos e também conectar pesquisadores geograficamente dispersos. A continuidade do desenvolvimento agrícola nos países em desenvolvimento, o menor custo de pesquisa coordenada e o investimento em melhoramento genético como ferramenta complementar ao controle químico também são argumentos que justificam os benefícios trazidos por essas redes. Entre as publicações, o termo “gene” foi o que predominou na análise da densidade de termos. Os autores das áreas de biotecnologia, genética, reprodução de plantas e desenvolvimento de biótipos resistentes são os que mais colaboram e também os que têm maior número de publicações, reafirmando a importância do melhoramento e da cooperação para a segurança alimentar. Nas trocas de germoplasma, o Peru e o México já foram alvos de inúmeras expedições internacionais – especialmente dos países europeus - para coleta de materiais. Ainda assim, a maioria dos países tem ligações consigo mesmos maiores do que com outros países, reforçando a ideia de que os programas de melhoramento nacionais colaboram mais entre si do que com de outros países. Alemanha e Holanda se destacam frente aos demais países com relação à quantidade de cultivares resistentes. Ambos apresentam também o maior número de colaborações mútuas, sinalizando a ocorrência de acordos bilaterais. Já Índia e China, apesar de serem os maiores produtores mundiais de batata, pouco pesquisam sobre o tubérculo. De maneira geral, este estudo contribui para a identificação de “quem colabora com quem” e corrobora a importância do “trabalho conjunto” na solução de desafios coletivos, como o manejo de doenças em plantas. Juntos, os três artigos demonstram que a cooperação tem papel relevante no melhoramento genético de plantas, por ser a essência das redes, ser destaque nas publicações da área do melhoramento genético e também por ter papel central no desenvolvimento de cultivares resistentes a doenças. Assim, suas implicações tornam possível entender a cooperação enquanto abordagem fundamental para a mitigação de doenças em plantas e dos riscos de insegurança alimentar mundial. Plant diseases can cause heavy losses and pose a real risk to global food security. To meet this challenge, cooperation among agribusiness stakeholders is fundamental. Thus, this thesis aims to measure and analyze the role of cooperation - scientific collaboration - in the management of diseases in plants, specially wheat and potato. Therefore, three studies are presented on this theme. The first study aims to characterize and study the functioning of some agricultural research networks that monitor pathogens, develop and distribute disease resistant cultivars, and sequence wheat and potato genomes. In it, it is also discussed how some pathogens may threaten the stability of wheat and potato production in the world, especially the fungus Puccinia graminis f. sp. tritici, that causes stem rust in wheat, and the oomycete Phytophthora infestans, that causes late blight in potato. Different institutions, such as consortia, research centers and established institutions are considered to illustrate their involvement in networks and to discuss their activities. The second article seeks to measure scientific collaboration in publications available in Web of Science through co-authorship analysis. The objective was to map countries that collaborate scientifically in the area of food security. We considered articles published in the period from 1996 to 2016 and the results were analyzed using VOSviewer software. The third article seeks to map the germplasm exchanges conducted by potato breeding programs in the world to measure collaboration between countries. In this article, information was only used on the potato. Cultivars of potato resistant to late blight were selected based on two databases, a European - European Cultivated Potato Database (ECPD) - and another Brazilian - Embrapa 's Potato Cultivars Catalog 2015. The construction of maps, charts and procedures was made in the Microsoft Excel, in the Tableau 10.1 and with RTBMaps version 1.0 software. Salton's measure was used for data normalization. The results suggest that collaborative research conducted by networks can be more beneficial than individual research by avoiding overlapping studies, saving time and resources, and also connecting dispersed researchers. The continuity of agricultural development in developing countries, the lower cost of coordinated research and the investment in genetic improvement as a complementary tool to chemical control are also arguments that justify the benefits brought by these networks. Among the publications, the term "gene" was the one that predominated in the analysis of the density of terms. The authors of biotechnology, genetics, plant breeding and the development of resistant biotypes are those who collaborate most, as well as those with the largest number of publications, reaffirming the importance of breeding and cooperation for food security. In the germplasm exchange, Peru and Mexico have already been targets of numerous international expeditions - especially European countries - for the collection of materials. Still, most countries have connections with themselves higher than other countries, reinforcing the idea that national breeding programs work more closely with one another than with other countries. Germany and the Netherlands stand out against the other countries in relation to the number of resistant cultivars. Both also have the largest number of mutual collaboration, signaling the occurrence of bilateral agreements. India and China, despite being the world's largest potato producers, do not research on the crop. Overall, this study contributes to the identification of "who collaborates with whom" and confirms the importance of "working together" in solving collective challenges such as plant disease management. Together, the three articles show that cooperation plays a significant role in the genetic improvement of plants, being the essence of the networks, being prominent in publications in the area of genetic improvement and also for having a central role in the development of cultivars resistant to diseases. Thus, its implications make it possible to understand cooperation as a fundamental approach to the mitigation of plant diseases and the risks of global food insecurity.

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19

Rodrigues, Michele Carvalho da Silva. "Avaliação e adequação da lavagem no beneficiamento da batata." [s.n.], 2011. http://repositorio.unicamp.br/jspui/handle/REPOSIP/256850.

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Orientador: Marcos David Ferreira Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Agrícola Made available in DSpace on 2018-08-19T15:37:33Z (GMT). No. of bitstreams: 1 Rodrigues_MicheleCarvalhodaSilva_M.pdf: 1787890 bytes, checksum: ad42d636315e1e015773f4c6f3929bd8 (MD5) Previous issue date: 2011 Resumo: O beneficiamento da batata lavada no Estado de São Paulo, destinada ao mercado in natura ou ao processamento, consome volume excessivo de água, provocando danos ao meio ambiente principalmente no descarte da água residual da etapa de lavagem. Tendo em vista a exigência do mercado consumidor por batata lavada, e a necessidade da redução do consumo de água utilizado para este tipo de beneficiamento, a hipótese deste trabalho é a de que é possível reduzir o consumo de água na etapa de lavagem da batata modificando os parâmetros de funcionamento dos equipamentos utilizados atualmente (vazão e rotação), mantendo a eficiência de limpeza, sem afetar a qualidade do produto. Sendo assim, o objetivo deste trabalho foi avaliar a etapa de limpeza em linhas de beneficiamento de batata lavada produzida no Estado de São Paulo, e propor modificações para redução no volume de água com manutenção da qualidade do produto e da eficiência de limpeza. Para tanto, inicialmente foi realizada a avaliação de desempenho da etapa de limpeza em unidades de beneficiamento de batata lavada no Estado de São Paulo, identificando o método de lavagem, os tipos de roletes/escovas, velocidade média do produto, e volume de água consumido. A partir do estudo de desempenho, foram propostas alterações para melhoria na etapa de limpeza com relação ao volume de água consumido e a limpeza do produto. A eficiência de limpeza, o consumo de água, e a influência do beneficiamento na qualidade da batata lavada foram avaliados e comparados nos sistemas propostos, onde foram avaliadas três rotações para as escovas, e três vazões de água na lavagem de tubérculos de dois solos com diferentes teores de argila. A qualidade do produto beneficiado foi avaliada por meio dos parâmetros: perda de massa fresca, coloração, danos físicos e firmeza. Neste trabalho foi possível verificar que o consumo de água nas unidades de beneficiamento pode ser reduzido, mantendo a eficiência de limpeza do produto, apenas com ajustes de vazão e rotação do equipamento de lavagem. Com relação à qualidade, verificou-se o incremento na perda de massa e incidência de brotamento, e redução da e firmeza da batata lavada em comparação aos tubérculos não lavados Abstract: The washing for potatoes in São Paulo, for the fresh market or industry, consumes excessive amounts of water, causing damage to the environment mainly due to waste water discharge from the washing step. Considering the requirement of the consumer market for washed potatoes, and the need to reduce water consumption, the hypothesis is that it is possible to reduce water consumption on the washing of potato just modifying the configuration of the equipment currently used (flow and rotation), and maintaining the cleaning efficiency without affecting quality. Therefore, the main goal was to evaluate the cleaning step in processing lines of washed potatoes produced in the state of Sao Paulo, and propose modifications to reduce the amount of water and with maintenance of product quality and cleaning efficiency. Therefore, early, characterization of the cleaning step was made in processing and classification units of washed potatoes in the state of Sao Paulo, identifying the method of washing used, types of rollers / brushes, average speed of the product, and water volume consumed on this step. From the characterization study, changes were proposed in the cleaning step that would improve the efficiency with respect to water consumption and cleaning product. The cleaning efficiency, water consumption, and influence of improvement in the quality of washed potatoes were evaluated and compared in the proposed systems. The quality of the processed product was evaluated by the following parameters: weight loss, color, physical damage and firmness. In this study, it was possible to verify that water consumption on processing units can be reduced maintaining cleaning efficiency, only adjusting water flow and rotation of the equipment. Related to tuber quality, it was also observed an increase of mass and firmness loss, and sprouting of washed potatoes compared with unwashed tubers Mestrado Tecnologia Pós-Colheita Mestre em Engenharia Agrícola

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20

Tofoli, Jesus Guerino. "Ação de fungicidas e indutores de resistência no controle da requeima e pinta preta na cultura da batata." Universidade de São Paulo, 2011. http://www.teses.usp.br/teses/disponiveis/11/11136/tde-28042011-155516/.

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A requeima, causada pelo oomiceto Phytophthora infestans e a pinta preta, causada pelo fungo Alternaria solani, estão entre as doenças mais importantes e destrutivas da cultura da batata no Brasil e no mundo. Considerando a importância do controle químico em sistemas integrados e a necessidade de se conhecer detalhadamente o desempenho de fungicidas e indutores de resistência visando à sustentabilidade da produção, o presente estudo objetivou caracterizar e comparar a ação preventiva, residual, curativa, anti-esporulante e resistência à chuva de fungicidas em condições controladas, bem como, avaliar em campo o potencial de controle de fungicidas e indutores de resistência e seus reflexos sobre a produtividade total e comercial de tubérculos. Todos os fungicidas promoveram elevada ação preventiva contra a requeima e a pinta preta. Os fungicidas sistêmicos ou com alta tenacidade proporcionaram controle das duas doenças até os 12 DAP, enquanto que os fungicidas translaminares até os 9 DAP. Quanto à ação curativa e anti-esporulante destacaram-se principalmente os fungicidas sistêmicos aplicados até as 24 horas após a inoculação (HAI). Os fungicidas translaminares foram capazes de inibir a requeima quando aplicados até 12 HAI e os de contato destacaram-se apenas para ação preventiva. Semelhantemente, os fungicidas sistêmicos, translaminares ou com alta tenacidade foram os menos afetados pela chuva simulada. O aumento do tempo de secagem promoveu uma maior retenção ou absorção dos produtos reduzindo o impacto negativo da precipitação. Os melhores níveis de controle, produtividade e qualidade de tubérculos foram obtidos com os fungicidas mandipropamida+clorotalonil, fluopicolida+propamocarbe, dimetomorfe+ametoctradina, mandipropamida, fenamidona+propamocarbe, bentiavalicarbe+ fluazinam, seguidos de dimetomorfe+clorotalonil mefenoxam+clorotalonil e famoxadona+ cimoxanil+mancozebe para requeima e azoxistrobina+difenoconazol, picoxistrobina, piraclostrobina+metconazol, trifloxistrobina+tebuconazol, azoxistrobina, boscalida+ piraclostrobina, iprodiona+pirimetanil e ciprodinil para pinta preta. Acibenzolar-s-metílico (ASM) reduziu a severidade da requeima e da pinta preta, porém, promoveu aumento da produtividade, apenas no campo de requeima. O fosfito de potássio (FP) também reduziu a severidade da requeima, no entanto, não influenciou na produtividade. Com exceção de mandipropamida, a adição de ASM à mefenoxam+mancozebe, cimoxanil+mancozebe e mancozebe promoveu aumento do controle da requeima, no entanto, apenas quando em mistura com mancozebe proporcionou aumento na produtividade. A adição de FP à mandipropamida, mefenoxam+mancozebe, cimoxanil+mancozebe, mancozebe e de ASM à azoxistrobina e difenoconazol não refletiu no controle da requeima, da pinta preta e na produtividade, respectivamente. Mancozebe e ASM não diferiram quanto severidade, progresso da pinta preta e produtividade, porém mancozebe+ASM foi superior ao ASM. A adição de ASM a programas de aplicação reduziu a requeima e a pinta preta e incrementou a produtividade apenas quando adicionados a programas onde prevaleceram fungicidas translaminares e de contato. O FP não influenciou nenhum dos programas testados para requeima. Late blight, caused by the oomycete Phytophthora infestans and early blight, caused by the fungus Alternaria solani, are among the most destructive diseases of potato crops in Brazil and worldwide. Considering the importance of the chemical control on integrated systems and the need for detailed knowledge of the performance of resistance inducers and fungicides targeting the sustainability of production, the present study aimed to:1- characterize and compare the preemptive, residual, curative, antisporulative action and rain resistance of fungicides under controlled conditions; 2-: evaluate, under field conditions, the control potential of fungicides and resistance inductors and their effects on the total and commercial yield of potato tubers. All fungicides tested provided a high pre-emptive action against late and early blight. The systemic fungicides or high tenacity ones provided control of both diseases until 12 days after application, while translaminar ones until 9 days after application. As for the curative and anti-sporulative action, the systemic fungicides stand out when applied until 24 hours postinoculation, while the translaminar ones inhibited late blight when applied until 12 hours postinoculation. The contact fungicides stand out concerning pre-emptive action only. Similarly, systemic, translaminar and high tenacity fungicides were less affected by the simulated rain. An increase in drying time promoted higher retention and absorption of the products, so decreasing the negative precipitation impact. The better levels of control, yield and tubers quality were reached with the use of the following fungicides in the control of late blight: mandipropamid+chlorothalonil, fluopicolide+propamocarb, dimetomorph+ametoctradin, mandipropamid, fenamidone+ propamocarb, bentiavalicarb+fluazinam, followed by dimetomorph+chlorothalonil, mefenoxam+ chlorothalonil and famoxadone+cymoxanil+mancozeb. In the control of early blight the most efficient were: azoxystrobin+difenoconazole, pycoxystrobin, pyraclostrobin+metconazole, trifloxystrobin+tebuconazole, azoxystrobin, boscalid+pyraclostrobin, iprodione+pyrimethanil and cyprodinil. Acibenzolar-s-methyl (ASM) reduced the severity of late and early blight, but promoted an increase in the tuber yield only in late blight affected field. Potassium phosphite (Pp) also reduced the severity of late blight, although it did not have influenced the yield. Except for mandipropamid, the addition of ASM to mefenoxam+mancozebe, cymoxanil+mancozeb or mancozeb led to a better control of late blight, but only when mixed with mancozeb it promoted increase in the yield. Addition of Pp to mandipropamid, mefenoxam+mancozeb, cymoxanil+mancozeb, mancozeb and ASM to azoxystrobin, difenoconazole did not result either in the control of late and early blight or in an increase of yield. Mancozeb and ASM did not differ as for severity, progress of late blight and increasing yield, but however, mancozeb+ASM had a superior efficiency than ASM. Addition of ASM to application programs reduced late and early blight and increased yield only when added to programs in which prevailed translaminar and contact fungicides. Pp did not influenced any of the tested programs against late blight.

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21

Romberg, Megan Kara. "Research into two diseases of solanaceous crops in California : 1) characterization of potato early dying in Kern County, California. 2) phylogeny, host range and molecular detection of Fusarium solani f.sp. eumartii, causal agent of Eumartii wilt in potato, foot rot of tomato and stem rot of pepper /." For electronic version search Digital dissertations database. Restricted to UC campuses. Access is free to UC campus dissertations, 2005. http://uclibs.org/PID/11984.

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22

Wondimagegne, Eshetu. "Bacterial wilt of potato in Ethiopia." Thesis, University of East Anglia, 1993. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.335193.

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23

Opoku-Ameyaw, Kwabena. "Utilizing radiation #wasted' by the potato crop." Thesis, University of Reading, 1991. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.481103.

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24

Mohabir, G. "Biochemical investigations of yield-limitations in potatoes (Solanum tuberosum L.) under warm tropical conditions." Thesis, University of Reading, 1988. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.380838.

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Monday, Tyler Anthony Foshee Wheeler G. "Industrial sweetpotato a viable biofuel crop for Alabama /." Auburn, Ala, 2009. http://hdl.handle.net/10415/1763.

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26

Fowler, James H. "Effect of plant arrangement and density on growth development and yield of two potato varieties." Thesis, University of Cambridge, 1988. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.257946.

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27

Joshi, Samudra Lal. "Ecology and management of the red ant Dorylus orientalis Westwood in Nepal." Thesis, Imperial College London, 1998. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.300969.

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28

Ramadan, Mahmoud Hany Abd El-Aziz. "Modelling for irrigation scheduling with particular reference to the potato crop." Thesis, Imperial College London, 1986. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.300101.

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29

McKenzie, John. "The effects and residues of maleic hydrazide within the potato crop." Thesis, University of Glasgow, 1989. http://theses.gla.ac.uk/2551/.

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This thesis describes the observations of field trials and analytical investigations of the residues of maleic hydrazide (1,2-dihydro-3,6-pyridazinedione) known as MH. MH is marketed in a formulation called `Fazor' and was introduced to the United Kingdom under PSPS (Pesticide Safety Precaution Scheme) in 1985. It is targeted at sprout suppression of ware tubers in store with the added benefits of increased marketable yield and reduced groundkeepers. Two field trials were conducted to investigate the sprout inhibition of MH and its effect on yield. Both field trials used a popular ware seed (c.v. Maris Piper) grown under typical growth conditions and treated with Fazor(5 kg/500 litres/hectare) under optimum conditions. Treated potatoes were observed to have typical characteristics of a break in apical dominance. Every eye on the tubers was active and formed spikelets that developed into growths similar in appearance to a small cauliflower head. It was also noticed that sprout suppression was not complete. A proportion of potatoes had inadequate suppression. Some showed no characteristics of MH, typical of an untreated potato. The inadequate sprout suppression was investigated by analysing the MH distribution and the comparison of sprout suppression. MH treated plots were found to have slightly lower yields than untreated plots. This reduction in yield was not shown to be statistically significant. Two methods to calculate the residues of MH were adapted. The first used the action of zinc in concentrated sodium hydroxide to produce hydrogen, which reduced and hydrolysed MH to hydrazine. The hydrazine was distilled and caught in an acid scrubber containing a colour reagent. The colour reagent and hydrazine combined to produce a coloured chromophore. The colour intensity was proportional to the amount of MH. This method was used to calculate the total MH. The second method calculated the amount of free MH (not metabolised or conjugated) by a methanol extraction, cleanup of the concentrate and analysis by high pressure liquid chromatography (HPLC). The total MH was roughly made up of three factions:- (1) Non-extractable MH (2) Methanol extractable MH (a) free MH (b) metabolised MH The uptake of MH over a four week period, after spraying Fazor, was assessed by harvesting at weekly intervals for four weeks and analysing the tubers by the above methods. The distribution of MH between individual tubers was investigated by calculating the MH in whole tubers. The distribution within individual tubers was calculated by analysing the skin, the outer flesh and the inner core. The distribution of MH between grades was calculated. The carryover of MH into processed foods was calculated by analysis of crisps and boiled potatoes from field treated plots. It was found that the MH accumulated in the potato tubers before one week and remained static up to four weeks. However, there was a fraction, a possible metabolite, that increased in concentration, whereas the free MH concentration decreased. Sprout suppression was found to be dependent on the total MH. Small tubers had lower concentrations than larger tubers. MH was found throughout the whole tuber with a slightly lower concentration in the core. MH was also found in fried and boiled potatoes and was identified as free MH. The metabolites of MH were investigated by applying radiolabelled MH to greenhouse grown potato plants. The potatoes were extracted by methanol and the concentrated extracts separated by thin layer chromatography (tlc). A metabolite was detected after exposing the plates to X-ray photographic plates. However, this metabolite was not successfully identified. This was due to the combination of low specific activity of the radiolabelled material, and the low quantity of metabolite produced. Hydrolytic enzymes were used to cleave possible conjugated metabolites in the potato juice concentrates. The action of a beta-D-glucosidase was found to increase the free MH. This would appear to suggest that a metabolite of MH is a conjugated product between MH and a glucose molecule. However, a conjugate could not be synthesized between uridine diphospho glucose (UDPG) and MH with soluble potato protein. There was no evidence to suggest that a metabolite is produced between MH and glutathione. It was suspected that MH would inhibit wound healing because it inhibits cell division. Cut potatoes treated with various concentrations of MH were examined histologically to assess cell division and suberin production. The rate of water loss from potato discs treated with MH was calculated. If the rate of water loss does not slow down because of chemical inhibition of the process, potatoes will lose weight and condition in store. No difference between control potatoes and MH treated potatoes was found at the beginning of a storage season. At the end of storage (four months), MH treated tubers had better wound healing than controls.

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30

Peddie, D. C. "Modelling and control of crop conditions in a bulk potato store." Thesis, University of Newcastle Upon Tyne, 1986. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.372933.

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31

Schroder, Michelle L. "Host plant preference of Rhopalosiphum padi (Hemiptera: Aphididae) and its role in selecting crop border plants to reduce Potato virus Y (PVY) in seed potatoes." Diss., University of Pretoria, 2014. http://hdl.handle.net/2263/79775.

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Winged Rhopalosiphum padi in search of good quality host plants transmit the non-persistent Potato virus Y (PVY) to seed potatoes. Planting a non-virus host plant as a border around the main crop can reduce PVY incidence, because aphids tend to land in high numbers at the edge of a field and the crop border acts as a virus sink. Using a trap crop could increase the number of aphids landing in the border. During host-plant searching behaviour, alate (winged) aphids respond to short (UV) and long (green - yellow) wavelength stimuli and plant volatiles. The present study evaluated R. padi preference for maize and wheat cultivars in comparison to potato cultivars to identify a potential crop border plant that is attractive to aphids for landing but does not support a high aphid population density. The study further served to develop selection criteria for potential crop border plants. To this end the landing and settling preference and reproductive rate of R. padi on three cultivars each of maize, potato and wheat were compared in choice and no-choice laboratory trials. The attractiveness of different shades of green, relative to differences in spectral reflectance of the crop cultivars, to R. padi was determined as well as olfactory responses of this species, to the plant cultivars tested. Landing and reproduction of R. padi suggested maize cultivars ‘6Q-121’ and ’78-15B’ are potential crop border plants. In choice and no-choice experiments, R. padi produced the highest number of offspring on wheat than on maize. In contrast, wheat cultivars had the greatest potential to be used as crop border plants based on percentage wavelength reflection in the green-yellow wavelength region. Rhopalosiphum padi preferred to land on yellow and lime colour targets with a maximum wavelength reflectance of 46% and 26%, respectively. The peak light reflectance of the crop plants ranged between 12% and 20%, with wheat reflecting the highest percentage of light. However, olfactory responses of R. padi indicated that maize ‘6Q-121’ may prove to be a suitable crop border plant. The volatiles emitted by maize ‘6Q-121’ did not contain compounds such as -farnasene, (E)-2- hexenal, indole and TMTT which are known to repel R. padi. On the other hand, R. padi did not distinguish between maize and wheat cultivars prior to landing, which indicates that both visual and olfactory cues are important in host plant selection behaviour and thus for selecting crop border plants. The results of the present study suggest that maize ‘6Q-121’ could be used as a crop border plant in seed potato production regions where R. padi is abundant, due to high aphid landing and low reproduction rates. In conclusion, a suitable crop border plant should be a preferred host plant and cultivar of the dominant aphid vector species in a seed potato production region. Potential plant cultivars should reflect a higher percentage of light in the green-yellow wavelength region than the main crop and the volatile profiles should preferably not contain compounds that are known to repel the aphid vector. Thesis (PhD)--University of Pretoria, 2014. Potatoes South Africa (PSA), and the Technology and Human Resources (THRIPP) Zoology and Entomology PhD Unrestricted

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32

Brewer, Marin Talbot. "Effects of Biological Control and a Ryegrass Rotation on Rhizoctonia Disease of Potato." Fogler Library, University of Maine, 2003. http://www.library.umaine.edu/theses/pdf/BrewerMT2003.pdf.

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33

Galvao, Aline Carolina. "Sweet Potato: A "Cluster" Approach to Improve the Crop Sustainability in Temperate Zones." Doctoral thesis, Università degli studi di Padova, 2019. http://hdl.handle.net/11577/3426829.

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Many cultures have the sweet potato how a staple food and that make it is the seventh of the most cultivated crops in the world. Its large capacity of adaptation is due to genetic and phenotypic diversity. The storage roots are the most consumption edible part but are possible to use the other parts of the plant too. Flesh can be orange, purple white, cream, or yellow, and the amount of vitamin and minerals can vary on the colour. In Europe, sweet potato is a niche crop mainly grown in the Mediterranean areas, with predominant white fleshed genotypes. Generally, its associated with subsistence agriculture is very diffuse in developing countries and according to the FAO, in 2013, the consumption per capita per year is estimated to be 14.6 kg in Africa, 9.3 kg in Asia, 5.3 kg in Oceania, 2.9 kg in America and < 0.5 kg in Europe. Although in Europe its consumption is still small, it has grown exponentially, in the period from 2010 to 2014 the amount imported doubled. These genotypes empirically cultivated are inherently inferior regarding nutritional quality, and nowadays, there is limited information about new genetics materials. The biochemical and nutraceutical characterisation of them is the first step to finding the accesses with interesting traits to temperate zones. This Convolvulaceae has as a feature a wide phenotypic diversity due to its autohexaploidia (2n = 6x = 90), and to obtain genotypes with elevated levels of heterosis is necessary to select parents with high genetic variability. The morphological e biochemical characterisation is the less expensive methods to evaluated a dissimilarity among the genotypes. The sweet potato is rich in vitamin C, Vitamin A, and antioxidants. The extracts from sweet potato exhibit strong radical scavenging and has anti-inflammatory, antimicrobial, and antihypertensive activities, and the pharmacological potential of the species is already described in the literature. Moreover, we assign the intrinsic value of each genotype of the DAFNAE genetic bank then classify each one according to its aptitudes biochemical and nutritional. The results suggest that some genotypes have substantial amounts of starch, sucrose or glucose, may become a new source of these products. The elevated levels of vitamins and minerals indicate some accesses to be used for biofortification of foods, such as cakes, soups or biscuits, to increase their nutritional aspects. A characteristic of the horticulture is the intensification of the crop grow, and the sector has to need to reinvent each time to quick. So, to improve a tropical crop in temperate condition, so many factors need to be evaluated. The sweet potato has high productive potential and can reach 40 t/ha. However, the European yield does not attain 20 ton/ha. The production of cuttings and the fertilisation are the first steps to advance the crop science of sweet potato because they have a straight influence on the homogeneity growth and yield. In this context, this present research has the aim to hone the growth and competitiveness of the sweet potato in the temperate climate zone.

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34

Ferebee, James Harrison IV. "New Herbicide Strategies for Weed Management in Pumpkin and Soybean and Potato Vine Desiccation." Thesis, Virginia Tech, 2019. http://hdl.handle.net/10919/86611.

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Weed control and desiccation are routinely executed with herbicides. Potato vine desiccation facilitates harvest, improves skin set, and regulates tuber size. Saflufenacil, glufosinate, saflufenacil plus glufosinate, and carfentrazone plus glufosinate were compared to diquat applied at 43, 31, and 17% B potatoes; similar vine desiccation (14 days after treatment), skin set, and yield were noted amongst treatments. Residual herbicides are routinely used for weed control in pumpkin. Fluridone and acetochlor formulations applied preemergence were evaluated in direct-seeded pumpkin compared to other labeled herbicides. Fluridone resulted in total crop loss following heavy rainfall immediately after planting; less rainfall resulted in transient injury. Acetochlor formulations resulted in significant pumpkin injury (34 to 39%) 14 days after planting. S-metolachlor controlled weeds similar to acetochlor without significant injury. Palmer amaranth has developed resistance to six different herbicide modes of action. The weed grows rapidly and is best controlled <10 cm in height. To control glyphosate and ALS- resistant biotypes, fomesafen plus dicamba were applied at first postemergence (POST) to small Palmer amaranth (<5 cm, 0 d) and at simulated delays of 7, 14, 21, and 28 d. All plots received lactofen plus dicamba 14 days after first POST. Palmer amaranth control 14 days after first POST was 100% when delayed 0 or 7 d and 62% at the 28 day delay; control increased to 88% following lactofen plus dicamba applied second POST. Yield was significantly reduced when first POST was delayed 28 days at one location. Master of Science in Life Sciences Herbicides effectively control weeds by either applying them to the soil prior to emergence or applying them to foliage. Herbicides are used for desiccation of potato vines to facilitate harvest, improve skin set, and regulate tuber size. Potatoes with tougher skin have a longer shelf life and are more resistant to disease. Potato grade classifications include size chef, A, and B potatoes. Size B potatoes hold the greatest value for redskinned potatoes. Experiments were conducted in Virginia to evaluate saflufenacil, glufosinate, saflufenacil plus glufosinate, and carfentrazone plus glufosinate as desiccants compared to diquat applied at 43, 31, and 17% B potatoes. All desiccants resulted in similar vine desiccation 14 days after treatment, skin set, and yield. This research demonstrates that glufosinate and saflufenacil are effective alternatives to diquat for potato vine desiccation; however, further research is needed to evaluate the safety of saflufenacil applied to potatoes prior to harvest. Soil applied herbicides are commonly used in pumpkin production. Fluridone and two acetochlor formulations, herbicides that effectively control troublesome weeds in other crops, were evaluated for pumpkin production in addition to fomesafen, ethalfluralin, clomazone, halosulfuron, and S-metolachlor. Fluridone and acetochlor formulations resulted in significant pumpkin injury early in the growing season and total crop loss was observed by fluridone in 2018. Fomesafen significantly reduced pumpkin iv stand and yield. S-metolachlor, a member of the same chemical family as acetochlor, provided similar weed control without significant pumpkin injury. This research demonstrates that fluridone and acetochlor formulations are poor candidates for pumpkin production. Palmer amaranth is a troublesome weed in soybean that grows rapidly and is resistant to many herbicides. Palmer amaranth is best controlled at a height of 10 cm or less, but timely applications are not always feasible. Fomesafen plus dicamba were applied to small Palmer amaranth (<5 cm, 0 day) and at simulated delays of 7, 14, 21, and 28 days. All treatments received lactofen plus dicamba 14 days after the initial postemergence. Palmer amaranth control 14 days after first postemergence was 100% when application was delayed 0 or 7 day whereas Palmer amaranth control was 62% when first postemergence was delayed 28 days. Lactofen plus dicamba applied second postemergence increased control to 88% when the first postemergence was delayed 28 days. Compared to nontreated plots, Palmer amaranth biomass was reduced 99% by all treatments. This research demonstrates that fomesafen plus dicamba followed by lacofen plus dicamba can be effective for rescue control of Palmer amaranth.

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35

Palumbo, John C., Athayde Jr Tonhasca, and David N. Byrne. "Sampling Schemes and Action Thresholds for Sweet Potato Whitefly Management in Spring Melons." College of Agriculture, University of Arizona (Tucson, AZ), 1994. http://hdl.handle.net/10150/214720.

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Early season infestations of sweet potato whiteflies, Bemisia tabaci ( Gennadius) were monitored in fields of cantaloupe, Cucumis melo L., near Yuma, Arizona. We used these data to describe the relationship between the proportion of infested leaves and mean adult population density for the entire field. This model was used to develop a binomial sampling plan based on a presence- absence approach. We evaluated the model with three independent data sets, and the level of agreement between the model and data was reasonable for pest management purposes. A minimum sample size of 200 leaves is suggested for maximum accuracy. By turning over 50 leaves in the four quadrants of a field and determining what proportion have whiteflies (i.e., are there whitefly adults on the leaf or not), growers can estimate field populations. We recommend that if 60% of the sampled leaves have whiteflies then it is time to make a pesticide application because that tells you that population levels are approaching 3 adults per leaf.

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36

Paget, Mark Frederick. "Genetic evaluation models and strategies for potato variety selection." Thesis, University of Canterbury. Forestry, 2014. http://hdl.handle.net/10092/9953.

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A series of studies are presented on the genetic evaluation of cultivated potato (Solanum tuberosum L.) to improve the accuracy and efficiency of selection at various stages of a breeding programme. The central theme was the use of correlated data, such as relationship information and spatial and across-trial correlations, within a linear mixed modelling framework to enhance the evaluation of candidate genotypes and to improve the genetic response to selection. Analyses focused on several social and economically-important traits for the enhancement of the nutritional value, disease resistance and yield of potato tubers. At the formative stages of a breeding scheme, devising a breeding strategy requires an improved understanding of the genetic control of target traits for selection. To guide a strategy that aims to enhance the micronutrient content of potato tubers (biofortification), univariate and multivariate Bayesian models were developed to estimate genetic parameters for micronutrient tuber content from a breeding population generated from crosses between Andean landrace cultivars. The importance of the additive genetic components and extent of the narrow-sense heritability estimates indicated that genotypic 'individual' recurrent selection based on empirical breeding values rather than family-based selection is likely to be the most effective strategy in this breeding population. The magnitude of genetic correlations also indicated that simultaneous increases in important tuber minerals, iron and zinc, could be achieved. Optimising selection efficiency is an important ambition of plant breeding programmes. Reducing the level of candidate replication in field trials may, under certain circumstances, contribute to this aim. Empirical field data and computer simulations inferred that improved rates of genetic gain with p-rep (partially replicated) testing could be obtained compared with testing in fully replicated trials at the early selection stages, particularly when testing over two locations. P-rep testing was able to increase the intensity of selection and the distribution of candidate entries across locations to account for G×E effects was possible at an earlier stage than is currently practised. On the basis of these results, it was recommended that the full replication of trials (at the first opportunity, when enough planting material is available) at a single location in the early stages of selection should be replaced with the partial replication of selection candidates that are distributed over two locations. Genetic evaluation aims to identify genotypes with high empirical breeding values (EBVs) for selection as parents. Using mixed models, spatial parameters to target greater control of localised field heterogeneity were estimated and variance models to account for across-trial genetic heterogeneity were tested for the evaluation of soil-borne powdery scab disease and tuber yield traits at the early stages of a selection programme. When spatial effects improved model fit, spatial correlations for rows and columns were mostly small for powdery scab, and often small and negative for marketable and total tuber yield suggesting the presence of interplot competition in some years for tuber yield traits. For the evaluation of powdery scab, genetic variance structures were tested using data from 12 years of long-term potato breeding METs (multi-environment trials). A simple homogeneous correlation model for the genetic effects was preferred over a more complex factor analytic (FA) model. Similarly, for the MET evaluation of tuber yield at the early stages, there was little benefit in using more complex FA models, with simple correlation structures generally the most favourable models fitted. The use of less complex models will be more straightforward for routine implementation of potato genetic evaluations in breeding programmes. Evaluations for (marketable) tuber yield were extended to multi-location MET data to characterise both genotypes and environments, allowing a re-evaluation of New Zealand MET selection strategies aimed at broad adaptation. Using a factor analytic mixed model, results indicated that the programme’s two main trial locations in the North and the South Islands optimised differentiation between genotypes in terms of G×E effects. There was reasonable performance stability of genotypes across test locations and evidence was presented for some, but limited, genetic progress of cultivars and advanced clonal selections for tuber marketable yield in New Zealand over recent years. The models and selection strategies investigated and developed in this thesis will allow an improved and more systematic application of genetic evaluations in potato selection schemes. This will provide the basis for well informed decisions to be made on selection candidates for the genetic improvement of potato in breeding programmes.

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37

Salmazo, Paula Bianca. "Efeitos de subdoses de sulfoniluréias na produtividade e qualidade de tubérculos de batatas (Solanum tuberosum L.)." Universidade de São Paulo, 2009. http://www.teses.usp.br/teses/disponiveis/11/11136/tde-14122009-155549/.

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No cenário olerícola nacional, a produção de batata está em crescimento. Nas áreas produtoras de batata das regiões Sul e Sudeste é comum encontrar essa cultura em rotação com milho e trigo. O uso de alguns herbicidas do grupo químico das sulfoniluréias nas culturas anteriores tem causado sintomas de fitointoxicação nas lavouras de batata. As deformações dos tubérculos ocorrem no inicio da fase de tuberização, quando se nota numerosas rachaduras relacionadas à contaminação por sulfoniluréias. O objetivo deste trabalho de pesquisa foi avaliar a resposta de plantas de batata das cultivares Atlantic e Lady Rosetta, quanto à produtividade e qualidade dos tubérculos, submetidas a aplicação de subdoses dos herbicidas metsulfuron-methyl e nicosulfuron, utilizados nas culturas do trigo e milho respectivamente. O experimento foi instalado em condições de campo. Os herbicidas foram aplicados nas plantas de batata no início da fase de tuberização. A fitointoxicação causada pelos herbicidas foi avaliada na parte aérea, na produtividade e qualidade dos tubérculos. Ambas as sulfoniluréias, metsulfuron-methyl e nicosulfuron, causaram injúrias foliares nas cultivares de batata, sendo que na cultivar Atlantic esses sintomas não predizem os danos nos tubérculos, que foram inferiores aos esperados. As sulfoniluréias reduziram a produção de tubérculos de maior diâmetro em ambas as cultivares. A cultivar Atlantic teve redução na produção e produtividade causadas pela pulverização de nicosulfuron na dose recomendada para a cultura do milho, e não foi afetada pelas pulverizações de metsulfuron-methyl. A cultivar Lady Rosetta foi afetada por ambas as sulfoniluréias nas maiores doses e pelo nicosulfuron também em dose 10 vezes menor àquela recomendada para a cultura do milho. A produção de tubérculos inviáveis na cultivar Atlantic foi devido à incidência de rachaduras, podendo chegar a 16,11% com a pulverização de metsulfuron-methyl e até 91,33% com nicosulfuron. Na cultivar Lady Rosetta a produção de tubérculos inviáveis caracterizou-se por sintomas de distúrbios fisiológicos, chegando até 78,26% e 88,44% com pulverização de metsulfuron-methyl e nicosulfuron respectivamente. As cultivares Atlantic e Lady Rosetta não perderam produtividade nem qualidade dos tubérculos após aplicação de metsulfuron-methyl ou nicosulfuron nas subdoses testadas. Potato production increases in the brazilian horticultural scene. Its common to find this crop in rotation with wheat and maize in the south and southeast production areas in Brazil. The use of some sulfonylureas herbicides in previous crops might cause phytotoxicity symptoms in potato. Tuber malformation take place in the beginning of tuberization, when can be noted tuber cracking related to sulfonylureas contamination. This trial aimed to assess the tuber quality and productivity of potato cultivars Atlantic and Lady Rosetta, subjected a application of low ates of metsulfuron-methyl and nicosulfuron, used previously in wheat and maize crops respectively. The trial was carried out in field conditions. The herbicides were sprayed in potato plants in the beginning of the tuberization phase in different rates. The sulfonylureas phytotoxicity was evaluated in the vegetative part and in the tuber quality and yield. Sulfonylureas, metsulfuron-methyl and nicosulfuron, caused foliar injuries in the potato cultivars, being that in Atlantic cultivar these symptoms do not predict tuber damages, that was below expectations. The sulfonylureas also reduced the production of tubers with larger caliber. The Atlantic cultivar decreased the production and the yield because of the nicosulfuron sprayed in maize recommended dose but was not affected by metsulfuronmethyl treatments. The Lady Rosetta cultivar was affected by both of sulfonylureas in the highest doses, such recommended for other crops, and also by nicosulfuron ten times diluted. The production of tuber unachievable for commercialization by the Atlantic cultivar was due to cracking, leading to 16.11% of cracked tubers after metsulfuronmethyl spray and 91.33% with nicosulfuron. In the Lady Rosetta cultivar it was characterized by malformation and second growth, achieving 78.26% and 88.44% of deformed tubers after metsulfuron-methyl and nicosulfuron sprays respectively. Both of the cultivars did not reduce tuber quality and yield after pulverization of metsulfuronmethyl or nicosulfuron in those low rates tested.

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38

Ampong, Joseph Eric. "Utilization of 'wasted' solar radiation in the potential growing season by the potato crop." Thesis, University of Reading, 1994. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.385056.

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39

Ullrich, Silke. "Weed Population Dynamics in Potato Cropping Systems as Affected by Rotation Crop, Cultivation, and Primary Tillage." Fogler Library, University of Maine, 2000. http://www.library.umaine.edu/theses/pdf/Ullrich.pdf.

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40

McPartlan, Helen Clare. "Transgenic potatoes (Solanum tuberosum) : gene dispersal and stability." Thesis, University of Cambridge, 1992. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.241045.

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41

Champagne, Antoine. "Diversité chimique et biofortification des plantes à racines et tubercules tropicales cultivées : caractérisation des parents et élaboration de protocoles permettant l'optimisation de la sélection." Thesis, Saint-Etienne, 2010. http://www.theses.fr/2010STET4017.

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L’agrobiodiversité s'étudie au niveau génotypique mais également au niveau de l'expression chimique de ce génotype, le chimiotype. Les plantes à racines et tubercules tropicales (manioc, patate douce, ignames et taros) sont multipliées par voie asexuée et les bases génétiques sont bien souvent étroites chez les cultivars traditionnels. Malgré les faibles diversités génétiques révélées à l'aide de marqueurs ADN, les chimiotypes sont très variables et leur étude est riche d’informations. Ces cultures vivrières, plantes amylacées mais aussi sources de molécules intéressantes pour les industries alimentaire et pharmaceutique, tiennent un rôle déterminant dans la garantie de la sécurité alimentaire des pays du Sud. Dans cette optique, leur amélioration génétique par voie conventionnelle est une contribution majeure aux enjeux actuels. De nombreux efforts restent néanmoins à réaliser pour analyser, compiler et disséminer les informations liées à la diversité des compositions et teneurs de plantes qui restent sous-utilisées ou non appréciées à leur juste valeur. La biofortiﬁcation qui vise une amélioration des propriétés nutritionnelles de ces plantes, présente de nombreux avantages dont le principal est de ne pas modifier les comportements alimentaires tout en permettant une meilleure adaptation environnementale des nouveaux génotypes. Leur amélioration passe par une sélection des parents basée sur leurs valeurs propres et le criblage de grands nombres d'individus hybrides. Le processus est long et fastidieux. L’élaboration de nouveaux outils permettant une optimisation de cette tâche est donc nécessaire. L'analyse d'échantillons représentatifs de la variabilité chimiotypique des collections du Vanouatou, un archipel Mélanésien abritant une riche agrobiodiversité, a permis d'étudier les relations entre composés majeurs, métabolites secondaire et préférences alimentaires locales. Les corrélations mises en évidence permettent d'apporter des éléments utiles à la compréhension du processus de sélection traditionnelle. L’identification des préférences visées par ce processus aident à comprendre les goûts et les attentes des consommateurs, et donc à mieux définir les idéotypes ciblés par les programmes d'amélioration. Ce travail a permis un premier criblage chimiotypique d'un grand nombre de cultivars appartenant aux deux espèces majeures, le taro (Colocasia esculenta) et la grande igname (Dioscorea alata). L'étude des caroténoïdes et des anthocyanes a permis d’identifier un certain nombre de cultivars comme parents potentiellement intéressants pour la biofortification mais aussi pour l'exploitation commerciale directe des clones. La caractérisation des hybrides, obtenus par panmixie et pollinisations libres au cours de cycles de sélection récurrente, indique que des gains importants sont obtenus pour des composés et métabolites essentiels. Les avancées réalisées dans le cadre de ce travail, et leurs conséquences pour les programmes d'amélioration génétique en cours, sont discutées. Les perspectives de mise au point de nouveaux outils de criblage et de nouvelles méthodes de caractérisation qui permettront in fine une meilleure approche de la biofortification de ces cultures vivrières, sont aussi envisagées Agronomic selection generates and maintains agrobiodiversity which can be regarded as an essential resource. To describe phenotypic diversity, genotypes as well as their chemical expression, chemotypes, have been widely used. Tropical root and tuber crops are vegetatively propagated and their genetic bases are often narrow. Therefore, unveiling the impressive phenotypic diversity is still rather difﬁcult through genotyping alone, whereas chemotype studies are very informative. Tropical root crops are staples and represent a good source of compounds related to health benefits and used in food and pharmaceutical industries. Those crops have key-roles to play in food security for developing countries and so plant breeding cannot be neglected. Biofortification is effective and does not imply change of dietary behaviours. Analysing, computing and compiling data bases for chemical data on diversity of neglected crops are still needed. Biofortification involving mass selection and proﬁling of numerous accessions is, however, time-consuming. Thus, efficient protocols and tools facilitating this process are required. Chemotypic variability within Vanuatu germplasm was characterised through core samples from different species and relationships between primary compounds, secondary metetabolites and local preferences have been studied. Useful correlations were shown, thus clarifying traditional selection process. This process has permitted the definition of ideotypes that will be interesting for the management of breeding programmes. At least for the two most important species in Vanuatu - taro Colocasia esculenta and the greater yam - Dioscorea alata -our work is the first broad screening of germplasm. The study of carotenoid and anthocyanin content indicates that some cultivars show potential for commercial exploitation. With the aim of improving staple foods by plant breeding, we identified accessions to be selected as parents for future crosses

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42

Renwick, Randall R. "Evaluation of a crop simulation model for potatoes." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1999. http://www.collectionscanada.ca/obj/s4/f2/dsk2/ftp01/MQ41762.pdf.

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43

Stone, Amanda Leigh. "Development of a more sustainable sweetpotato production system in Alabama." Auburn, Ala., 2005. http://repo.lib.auburn.edu/2005%20Fall/Thesis/STONE_AMANDA_35.pdf.

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44

Castelhano, Michael Joseph. "Staple Crop Diversity and Risk Mitigation - Potatoes in Bolivia." Thesis, Virginia Tech, 2008. http://hdl.handle.net/10919/35254.

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Rural areas of most developing nations are dependent on agriculture. In the most remote areas, sometimes referred to as the â less favored areasâ (LFAs), the economic importance of agriculture is paramount. An important obstacle to development in these areas is that agriculture is at the mercy of nature, which may not be particularly friendly. These areas have remained remote due to natural shortcomings causing economic development to occur slower than more advantaged areas elsewhere. Cochabamba Department, in central Bolivia, is home to some of these LFAs. Most Cochabamban producers are located in the â high climatic riskâ (CIP-WPA) Andean highlands. Farmers in LFAs surrounding Cochabamba city produce (among other things) potatoes for market and home consumption; the potato is the main source of food and income for most residents. Previous studies and anecdotal evidence have shown that Andean potato farmers may plant upwards of 10 varieties of potatoes on small amounts of land (Brush, 92). Because of the low rates of improved crop variety adoption in many LFAâ s, efforts are needed to understand farmer objectives and needs with respect to variety characteristics. The goal of this study is to determine how exposure to risk factors impacts potato planting decisions through demand for potato variety characteristics. The main source of data for this project is a survey of 145 farm households implemented during the last quarter of 2007 in 3 communities of Cochabamba. These data were used to estimate an econometric model that evaluated the role of household, regional and variety characteristics in farmer decision making. Decisions about planting each variety were modeled with a Tobit framework and estimated by the Heckman method (as suggested by Cameron and Trivedi), with the impact of individual variety characteristics restricted to be the same for each variety. Several hypotheses were confirmed such as the importance of yield, though many results were different than expected. Blight tolerance was found to be negatively correlated with selection, although most farmers report taking some kind of action to decrease damage from blight. Possible explanations for this negative correlation are discussed in this paper, and strategies for overcoming these obstacles are suggested. Master of Science

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45

Loayza, Loza Hildo. "Suivi expérimental du rendement de fluorescence des couverts végétaux par des techniques actives et passives. Application à la détection du stress hydrique." Electronic Thesis or Diss., Sorbonne université, 2022. http://www.theses.fr/2022SORUS465.

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La fluorescence de la chlorophylle (ChlF) est directement liée au processus photosynthétique. Cependant, au niveau de la canopée, ce lien physiologique entre la fluorescence et la photosynthèse peut être brouillé par les changements structurels de la végétation et les interactions entre la lumière du soleil et la structure 3D de la canopée. De plus, une grande partie de nos connaissances sur la relation entre la fluorescence et l'état physiologique des plantes provient d'études au niveau des feuilles réalisées dans des conditions de laboratoire. La signification physiologique de la ChlF au niveau de la canopée et dans des conditions naturelles est toujours un sujet de recherche majeur. Ce projet doctoral avait pour objectifs : 1. Etude du rendement de fluorescence de la chlorophylle au niveau de la canopée: nous décrivons un nouvel instrument, Ledflex, qui est un micro-LIDAR dédié à effectuer des mesures continues du rendement de fluorescence de la végétation. Ledflex a été appliqué avec succès dans des conditions de plein soleil pour établir la signature du stress hydrique sur la canopée du pois (Pisum Sativum). Dans des conditions bien irriguées, le cycle diurne du rendement de fluorescence observé (Fs) présente une forme en M avec un minimum (Fmin) vers midi supérieur au niveau observé à l’obscurité (Fo). Après plusieurs jours sans irrigation, Fs diminue et Fmin The chlorophyll fluorescence (ChlF) is directly related to the photosynthetic process. However, at canopy level this physiological link between fluorescence and photosynthesis may be blurred by structural vegetation changes and geometrical effects linked to interactions between sunlight and the three-dimensional structure of the canopy. Furthermore, much of our knowledge about the relationship between fluorescence and the physiological status of plants come from leaf level studies carried out under laboratory conditions. The physiological significance of ChlF at canopy level and under natural conditions is still a major subject of research and a source of uncertainties in the interpretation of SIF. This doctoral project aims were: 1. To study chlorophyll fluorescence yield at canopy level: we describe a new instrument, Ledflex, which is a micro-LIDAR dedicated to perform continuous measurements of vegetation fluorescence yield. Ledflex has been successfully applied under full sunlight conditions to establish the signature of water-stress on a pea (Pisum Sativum) canopy. Under well-watered conditions the Fs diurnal cycle present an M shape with a minimum (Fmin) at noon which is higher than the fluorescence level observed at predawn (Fo). After several days withholding watering, Fs decreases and Fmin

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46

Demon, Inez Manuela. "The effect of crop and pest management on the evolution within the sweet potato white fly, Bemisia tabaci." Thesis, Imperial College London, 2006. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.429386.

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Capiral, Mary Joy Josephine M. "Measurements of ammonia and nitrous oxide emissions from potato fields in Central Washington using differential optical absorption spectroscopy (DOAS), tracer dispersion, and static chamber methods." Pullman, Wash. : Washington State University, 2009. http://www.dissertations.wsu.edu/Thesis/Spring2009/m_capiral_042309.pdf.

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Thesis (M.S. in environmental engineering)--Washington State University, May 2009. Title from PDF title page (viewed on May 21, 2009). "Department of Civil and Environmental Engineering." Includes bibliographical references (p. 87-91).

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48

Leveau, Aymeric. "Caractérisation structurale de l'éliciteur du virus X de la pomme de terre (PVX) : recherche, chez les plantes cultivées, de gènes hôtes, impliqués dans la résistance liée à Rx." Thesis, Evry-Val d'Essonne, 2012. http://www.theses.fr/2012EVRY0036.

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De nos jours, les agents pathogènes des plantes, engendrent encore des pertes agricoles importantes. A terme, la solution la plus adaptée semble être la création de variétés de plantes cultivées présentant une résistance génétique à large spectre et durable. Créer de telles plantes nécessite la compréhension des mécanismes de résistance mis en jeu dans des pathosystèmes modèles, tels que celui impliquant le gène de résistance Rx et le virus X de la pomme de terre. Dans ce système, la protéine Rx intervient dans la perception d’un facteur d'avirulence issu du virus: sa protéine de capside (Cp). Cependant, les mécanismes moléculaires déclenchant la résistance chez la plante exprimant Rx demeurent obscurs. Cette étude s’est focalisée sur l’étape de reconnaissance de l’éliciteur viral par Rx. Une première approche a permis la mise en évidence d’un éliciteur minimal de 90 acides amine. L’étude d’un fragment légèrement plus grand par des méthodes de biochimie structurale, tend à exclure un modèle selon lequel, la différence de structuration tertiaire entre Cp élicitrice et Cp non élicitrice déterminerait la reconnaissance par Rx. Une seconde approche, de biologie moléculaire, a mis en évidence deux protéines hôte interagissant avec ce petit fragment éliciteur. L'étude s’est focalisée sur un gène codant un facteur de transcription, nbERF5, et a révélé que cette protéine interagit aussi bien avec les Cp de souches de Potexvirus avirulentes que virulentes dans la résistance liée à Rx, mais également avec la protéine de résistance Rx et l’intéracteur direct: RanGAP2. La poursuite de la caractérisation de cet ERF, permettra de déterminer son importance dans la résistance liée à Rx Nowadays, phytopathogenic agents are still causing significant agricultural losses. The most suitable option appears to be the creation of crop species carrying a genetic durable and broad spectrum resistance. In order to create such varieties, we need to understand the mechanisms underlying resistance, involved in model Pathosystems, Such as the one composed of the resistance gene Rx and the potato virus X. In that system, the host gene encodes a protein assimilated to a receptor implicated in the perception of an avirulence factor produced by the virus: its capside protein (Cp). Nevertheless, the molecular mechanisms triggering the resistance remain largely unknown. This study has been focused on the elicitor recognition mediated by Rx. A first approach led to the identification of a minimal elicitor containing 90 amino acids has. The structural characterization of a slightly larger protein fragment using biochemical methods suggested that the difference in the tertiary structuration of both elicitor and non-elicitor Cp would not be the determinant of Rx mediated recognition. Second, a molecular approach led to the discovery of two host proteins interacting with the small elicitor fragment. The work was focused on a transcription factor, nbERF5 and showed that this protein interacts similarly with elicitor or non-elicitor Cps of Rx mediated resistance. Interestingly, this gene product is able to directly interact with the Rx protein, but also with the direct interactor of Rx: RanGAP2, protein required for the Rx mediated resistance efficiency. Further characterization of this ethylen response factor will help us to understand its role in Rx mediated resistance

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49

Muñoz, Fernando. "Improving nitrogen management in potatoes through crop rotation and enhanced uptake." [Gainesville, Fla.] : University of Florida, 2004. http://purl.fcla.edu/fcla/etd/UFE0006202.

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50

Abolgasem, Tounis Maoloud Mohmed. "Effect of variety, fertilisation, rotation, crop protection and growing season on yield and nutritional quality of potato (Solanum tuberosum L.)." Thesis, University of Newcastle upon Tyne, 2014. http://hdl.handle.net/10443/2551.

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Potatoes (Solanum tuberosum L.) are the most important food crop in the world after rice and wheat. Potato tubers contain many types of essential nutrients. They contain high concentrations of carbohydrates and also vitamins, minerals and protein. They also contain toxic compounds called glycoalkaloids. Potato is classed as a protective vegetable because of its high vitamin C content. The objectives of this study were to determine the effects of different fertiliser types (composted cattle manure, mineral NPK fertiliser), pre-crop (beans, barley) crop protection protocols (organic, conventional) and growing season on the nutritional quality of vitamin C, glycoalkaloids and minerals and yield of different varieties of potato (Sante, Sarpo Mira, Nicola, Fontane, Agria and Cara). Field experiments were carried out during the 2010 and 2011 growing seasons at Nafferton Farm (Newcastle University). The experiment was a split split split plot-design. The main plot was crop rotation, the sub-plot was crop protection, the sub-sub plot was fertility management and sub-sub-sub plot was variety. The vitamin C content was determined by two different methods of analyses; colorimetric titration and high- performance liquid chromatography (HPLC). Mineral content was assessed by the Dumas combustion method at Sabanci University, Turkey. Total glycoalkaloids were determined according to the AOAC method 997. 13. A significant effect of fertilisation was detected for potato yield for both of years. In plots treated with NPK fertilisers, higher yield, compared to compost was obtained for both seasons. In addition conventional crop protection increased yield in both years. Pre-crop significantly affected yield in both years, with higher yields being recorded after beans than barley in 2010 while, a pre-crop of barley resulted in the significantly higher yield than beans in 2011. However, no significant difference between varieties was detected. Also, no significant interactions were detected for tuber yield in 2010. However a significant 2-way interaction between crop protection and pre-crop was observed in 2011, with a pre-crop of beans resulting in the highest yields under conventional crop protection, while a pre-crop of barley resulted in the significantly higher yield under organic crop protection systems. Results of the second growing season (2011) were based on the NUE potato experiment and showed that there was significant difference (P < 0.05) in yield between varieties, fertilisation iii and crop protection. A significant interaction between fertilisation and variety was detected for the yield. There was a significant effect of variety on tuber vitamin C content (P < 0.001), in 2010 and 2011. The concentrations were higher in Sante than Sarpo Mira. There were no significant influences of other treatments (fertility, rotation, crop protection). However, a 2-way interaction between fertilisation and variety was detected in 2011. In 2011 there was a significant effect of varieties on vitamin C content, but no significant effect of fertility and crop protection treatments. However, a significant interactions between fertility, variety and crop protection treatments was detected but only for the titration analysis for vitamin C content. There were no significant effects (P > 0.05) of fertilisation, pre-crop and crop protection on glycoalkaloid concentrations. However, a significant 3-way interaction between fertilisation, variety and rotation was detected for alpha solanine in 2011. A significant 3-way interaction between crop protection, fertilisation and variety was detected for alpha chaconine in 2010. In 2010 the mineral content (N, P, K, Na and Ca) of potatoes was significantly affected by fertilisation treatments. N, P and Ca contents were significantly increased by NPK application while the K and Na contents were significantly increased by compost application. In 2011 Ca contents were affected by fertilisation treatments only. Effects of variety, rotation and crop protection and interactions between factors were also detected for macro mineral contents. However, in 2011 no effect of pre-crop on tuber macronutrient concentration was detected. There was a significant difference in micronutrient concentration between variety, fertilisation and crop protection. No significant effect of rotations was detected for micronutrient concentrations in both of seasons. In conclusion, in both years, 2010 and 2011, variety significantly affected vitamin C content of potato tubers, but there were no significant effects of fertility, pre-crop and crop protection treatments irrespective of the analytical method (titration and HPLC) analysis. Sante tubers contained about 20% more vitamin C than Sarpo Mira. Therefore, it appears that variety choice is a reliable means of manipulating vitamin C as a component of tuber quality compared with other agronomic treatments. In addition, mineral content was also affected by treatments (fertility, variety, rotation and crop protection) and was highly variable. iv For the two years, similar results were obtained in alpha solanine and alpha chaconine content. Significant interactions between rotation, fertilisation and variety were only detected on alpha solanine content during 2011. Also, significant interactions between variety, fertility and crop protection were observed on alpha chaconine content during 2010. The 2010 and 2011 growing seasons appeared to have a significant effect on alpha solanine, macro minerals and micro minerals but did not appear to affect yield, vitamin C and alpha chaconine contents.

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