• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 361
  • 129
  • 37
  • 35
  • 16
  • 4
  • 3
  • 2
  • 2
  • 2
  • 1
  • 1
  • 1
  • Tagged with
  • 632
  • 219
  • 176
  • 109
  • 100
  • 82
  • 75
  • 70
  • 70
  • 68
  • 61
  • 44
  • 39
  • 38
  • 38
  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
331

Incorporação de fabáceas ao substrato de plantio para controle da podridão-de-escleródio (Sclerotium rolfsii Sacc.) em cubiu (Solanum sessiliflorum Dunal) / Incorporation of fabaceas in plant substrate to southern blight (sclerotium rolfsii sacc.) control in cubiu (solanum sessiliflorum dunal)

Laborda, Laysa de Paiva 14 December 2017 (has links)
Submitted by Gizele Lima (gizele.lima@inpa.gov.br) on 2018-02-28T13:39:44Z No. of bitstreams: 2 Dissertação - Laysa Laborda.pdf: 1672119 bytes, checksum: a5ad9008dca40f70d1eafafec4e93ca3 (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) / Made available in DSpace on 2018-02-28T13:39:44Z (GMT). No. of bitstreams: 2 Dissertação - Laysa Laborda.pdf: 1672119 bytes, checksum: a5ad9008dca40f70d1eafafec4e93ca3 (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) Previous issue date: 2017-12-14 / Fundação de Amparo à Pesquisa do Estado do Amazonas - FAPEAM / Cubiu (Solanum sessiliflorum Dunal) cultivation in the Amazonas state is limited by the high incidence of southern blight caused by the soilborne fungus Sclerotium rolfsii Sacc. The incorporation of plant material into the substrate changes the microflora present by increasing the organic matter content and by the plants decomposition exudates, which may be toxic or beneficial to the different microorganisms present on the substrate. The incorporated organic matter also increases the nutrient content available to the plant. The objective of this study was to evaluate the potential for control of southern blight by the incorporation of fresh comminuted biomass of four Fabaceae species: Erythrina fusca and Senna reticulata, native to Amazonia, and Desmodium heterocarpon and Gliricidia sepium, exotic to the substrate. The isolate of S. rolfsii was obtained from cubiu plants with disease symptoms and multiplied in autoclaved rice. Infestation of the substrate (argisol: chicken manure, 2: 1) was done with the incorporation of 10 g of colonized rice.L-1, in pots filled with 8 L of substrate, kept in a nursery. After 20 days of infestation, were incorporated 40 g of the Fabaceae biomass.L-1 substrate. The cubiu seedlings, 90 days after sowing, were transplanted one week after the incorporation of the Fabaceae. The experimental design was completely randomized, with three replicates and seven treatments: four species of Fabaceae and three controls, without the incorporation of biomass. In one control the substrate was not infested and in other, the plants were sprayed (9 mL.plant-1) twice, 50 days apart, with fungicide (Viper 700®, methyl thiophanate, 0.49 g a.i. for litter of water). Another experiment was carried out to evaluate the effect of doses of G. sepium incorporated into the substrate. The experiment had a completely randomized design and three replicates, with six treatments: incorporation of 40, 80, 120 and 160 g of G. sepium.L-1 substrate and two controls without incorporation of G. sepium. In one control, the plants were treated with fungicide. In this experiment, the pots were filled with 6 L of substrate infested as described in the previous experiment. In both experiments the disease and the inoculum incidence in the substrate were evaluated. In the first experiment, the data from the area below the disease progress curve were submitted to ANOVA and the means, compared by the Tukey test. In the second experiment, the data were submitted to regression analysis. In the first experiment the cubiu plants cultived in substrate with Fabaceae incorporation or treated with fungicide had the same southern blight incidence and in the pathogen suppression. In the second experiment, the incidence of southern blight was proportional to the G. sepium dose incorporated. With the incorporation of 139 g of G. sepium.L-1 no diseased plants were observed. Also the incorporation of 142 g G. sepium.L-1 substrate reduced the population of S. rolfsii in the substrate by 20%. / O cultivo do cubiu (Solanum sessiliflorum Dunal), no Amazonas, é limitado pela alta incidência da doença podridão-de-escleródio causada por Sclerotium rolfsii Sacc. A incorporação de material vegetal ao substrato de cultivo altera a microflora presente nesse substrato, tanto pelo aumento do teor de matéria orgânica, quanto pela liberação de substâncias, durante a decomposição desse material vegetal, que podem ser tóxicas, ou benéficas, a diferentes microrganismos presentes no substrato. A matéria orgânica incorporada aumenta, também, o teor de nutrientes disponíveis para a planta. O trabalho objetivou avaliar o potencial de controle da podridão-de-escleródio em cubiu por meio de incorporação, ao substrato de cultivo, de biomassa fresca triturada de quatro espécies de fabáceas: Erythrina fusca e Senna reticulata, nativas da Amazônia, e Desmodium heterocarpon e Gliricidia sepium, exóticas. O isolado de S rolfsii foi obtido de plantas de cubiu com sintomas da doença e multiplicado em arroz autoclavado. A infestação do substrato (argissolo: esterco de galinha, 2:1 ) foi feita com a incorporação de 10 g de arroz colonizado.L- 1 de substrato, em vasos preenchidos com 8 L de substrato, mantidos em viveiro. Após 20 dias da infestação, foram incorporadas 40 g da biomassa das fabáceas.L-1 de substrato. As mudas de cubiu, aos 90 dias da semeadura, foram transplantadas para os vasos uma semana depois da incorporação das fabáceas. O delineamento experimental foi inteiramente casualizado, com três repetições e sete tratamentos: quatro espécies de fabáceas e três testemunhas, sem a incorporação de biomassa. Em uma das testemunhas não houve infestação do substrato e em duas, o substrato foi infestado, sendo que em uma, as plantas foram pulverizadas (9 mL.planta-1) duas vezes, com intervalo de 50 dias, com fungicida (Viper 700®, tiofanato metílico, 0,49 g do i.a.L-1 de água). Outro experimento foi realizado avaliando-se o efeito de doses de G. sepium incorporadas ao substrato. O experimento teve delineamento inteiramente casualizado e três repetições, com seis tratamentos: incorporação de 40, 80, 120 e 160 g de G. sepium.L-1 de substrato e duas testemunhas sem incorporação de G. sepium sendo que em uma, as plantas foram tratadas com fungicida. Neste, os vasos tiveram 6 L de substrato infestado com a mesma dosagem de inóculo do experimento anterior. Em ambos os experimentos foi avaliada a incidência da doença e a densidade do inóculo no substrato. No primeiro experimento, os dados da área abaixo da curva de progresso da doença foram submetidos à ANOVA e as médias, comparadas pelo teste Tukey. No segundo experimento os dados foram submetidos à análise de regressão. No primeiro experimento as fabáceas não diferiram do fungicida na redução da incidência da podridão-de-escleródio e na supressão do patógeno. No segundo experimento, a redução da incidência da podridão-de-escleródio foi proporcional ao aumento da dose de G. sepium, apresentando 100% de controle com a incorporação de 139 g de G. sepium.L-1 de substrato. A dose de 142 g reduziu a população de S. rolfsii no substrato em 20%.
332

Banco de sementes vi?veis e manejo de plantas daninhas em sistemas de cultivo do tomateiro industrial / Viable seed bank and weed management in industrial tomato cropping systems

ROSA FILHO, Sebasti?o Nunes da 30 July 2017 (has links)
Submitted by Jorge Silva (jorgelmsilva@ufrrj.br) on 2018-01-26T16:05:57Z No. of bitstreams: 1 2014 - Sebasti?o Nunes da Rosa Filho.pdf: 2091591 bytes, checksum: f35a1bfbdc5bdd66764178c67ffba67b (MD5) / Made available in DSpace on 2018-01-26T16:05:57Z (GMT). No. of bitstreams: 1 2014 - Sebasti?o Nunes da Rosa Filho.pdf: 2091591 bytes, checksum: f35a1bfbdc5bdd66764178c67ffba67b (MD5) Previous issue date: 2017-07-30 / CAPES / Industrial tomato production is hampered by weed occurrence, which may reduce productivity through competition, affect the efficiency of products applied to crops and host commercially important diseases and pathogens. Thus, this study aimed to evaluate the occurrence and management of weeds in industrial tomato cropping systems in the Cerrado of Goi?s. In Chapter One, the viable seed bank was evaluated in areas with different weed management systems. The evaluation was made in two conventional tillage areas (CT); two with no-till (NT) and four with no-till and reduced soil preparation (RSP). The most frequent weeds were Conyza bonariensis, Cenchrus echinatus, Ipomoea aristolochiaefolia, Leonotis nepetifolia, Spermacoce latif?lia, Senna obtusifolia, Nicandra physaloides, Euphorbia heterophylla, Gnaphalium spp., Brachiaria plantaginea, Zea mays, Bidens pilosa, Macroptilium spp., , Solanum lycopersicum (tiguera), Commelina benghalensis and Sida rhombifolia. Among the soil preparation systems, reduced preparation (RSP) resulted in two species with higher germination: Phyllanthus tenellus and Oxaliss pp. Conventional tillage (CT) resulted in six species with the highest plant emergence number ? Ageratum conyzoides, Coronopus didymus, Portulaca oleracea, Eragrostis pilosa, Digitaria horizontalis and Solanum americanum. In Chapter Two, different systems of weed management in tomato crops for industrial processing under center-pivot irrigation were evaluated. The applied treatments were combinations between harrowing and chemical management with glyphosate, s-metolachlor, sulfentrazone and metribuzin-based products at different application periods. The variables plant population and ?Brix were not influenced by the treatments. There was statistical difference within the production components: twenty-fruit mass, yield per plant and productivity. Highest productivity was observed in the following treatments: a) harrowing thirty days after transplant (DAT), application of glyphosate (1,080 g ha-1), metribuzin (480 g ha-1) and s-metolaclhor (1,200 g ha-1) on the seventh DAT (83.39 t ha-1); harrowing on the 30th DAT, glyphosate (1,080 g ha-1) and s-metolachlor (1,200 g ha-1) on the seventh DAT (74.75 t ha-1); c) harrowing on the thirtieth DAT, glyphosate (1,080 g ha-1) on the 14th DAT and sulfentrazone (100 g ha-1) on the seventh DAT (73.06 t ha-1); d) harrowing on the 30th DAT, glyphosate (1,080 g ha-1) on the 14th DAT and s-metolachlor (1,200 g ha-1) on the seventh DAT (71.83 t ha-1) and; e) harrowing on the 30 DAT, glyphosate (1,080 g ha-1) and sulfentrazone (100g ha-1) on the seventh DAT (71.75 t ha.-1).With the ?no weeding? and ?harrowing-only? treatments, there was reduction of 63.82% and 69.29% in fruit productivity, respectively, compared to the weeded sample. The conclusion is that the applications of sulfentrazone (100 g ha-1) or s-metolachlor (1,200 g ha-1) in weed management systems using glyphosate revealed potential alternatives for industrial tomato production in Goi?s. / O cultivo de tomateiro industrial ? prejudicado pela ocorr?ncia de plantas daninhas que podem reduzir a produtividade por competi??o, afetar a efici?ncia de produtos aplicados nas lavouras e serem hospedeiras de pragas e pat?genos de import?ncia comercial. Com isso, este trabalho teve como objetivos avaliar a ocorr?ncia e o manejo de plantas daninhas em sistemas de cultivo de tomateiro industrial no Cerrado goiano. No primeiro cap?tulo, avaliou-se o banco de sementes vi?veis de ?reas com diferentes sistemas de manejo de plantas daninhas. As avalia??es foram feitas em duas ?reas de plantio convencional (PC), duas de plantio direto (PD) e quatro de plantio direto modificado com preparo reduzido do solo (PPR). As esp?cies de plantas daninhas mais frequentes foram Conyza bonariensis, Cenchrus echinatus, Ipomoea aristolochiaefolia, Leonotis nepetifolia, Spermacoce latif?lia, Senna obtusifolia, Nicandra physaloides, Euphorbia heterophylla, Gnaphalium spp., Brachiaria plantaginea, Zea mays, Bidens pilosa, Macroptilium spp., Solanum lycopersicum(tiguera), Commelina benghalensis, Sida rhombifolia. Entre os sistemas de preparo do solo, o preparo reduzido (PPR) apresentou duas esp?cies entre as de maior germina??o, a esp?cie Phyllanthus tenellus e a Oxalis spp. O plantio convencional (PC) apresentou tr?s esp?cies com maior n?meros de plantas emergidas, sendo Eleusine indica, Digitaria horizontalis e Amaranthus hybridus. O plantio direto (PD) teve seis esp?cies com maior emerg?ncia em compara??o aos outros manejos de solo, sendo Ageratum conyzoides, Coronopus didymus, Portulaca oleracea, Eragrostis pilosa, Digitaria horizontalis e a Solanum americanum. No segundo cap?tulo, objetivou-se avaliar diferentes sistemas de manejo de plantas daninhas na cultura do tomateiro para processamento industrial em parte de lavoura comercial sob piv? central. Os tratamentos utilizados foram combina??es entre o uso da gradagem e manejo qu?mico com produtos ? base de glyphosate, s-metolachlor, sulfentrazone e metribuzin em diferentes ?pocas de aplica??o. As vari?veis popula??o de plantas e ?Brix n?o foram influenciadas pelos tratamentos. Houve diferen?as estat?sticas para os componentes de produ??o: massa de vinte frutos, produ??o por planta e produtividade. As maiores produtividades foram observadas nos seguintes tratamentos: a) gradagem aos trinta dias antes do transplantio (DAT), aplica??o de glyphosate (1.080 g ha-1), metribuzin (480 g ha-1) e de s-metolaclhor (1.200 g ha-1) aos sete DAT (83,39 t ha-1); b) gradagem aos 30 DAT, glyphosate (1.080 g ha-1) e s-metolachlor (1.200 g ha-1) aos sete DAT (74,75 t ha-1);c) gradagem aos trinta DAT, glyphosate (1.080 g ha-1) aos 14 DAT e sulfentrazone (100 g ha-1) aos sete DAT (73,06 t ha-1); d) gradagem aos 30 DAT, glyphosate (1.080 g ha-1) aos 14 DAT e s-metolachlor (1.200 g ha-1) aos sete DAT (71,83 t ha-1) e ; e) gradagem aos 30 DAT, glyphosate (1.080 g ha-1) e sulfentrazone (100 g ha-1) aos sete DAT (71,75 t ha.-1). Nos tratamentos ?sem capina? e ?apenas gradagem?, houve redu??o de 63,82% e 69,29% na produtividade de frutos, respectivamente, em rela??o ? testemunha capinada. Conclui-se que as aplica??es de sulfentrazone (100 g ha-1) ou s-metolachlor (1.200 g ha-1), em sistemas de manejo de plantas daninhas contendo glyphosate, se revelaram alternativas potenciais na cultura do tomateiro industrial em Goi?s.
333

Utiliza??o de pel?cula de f?cula de mandioca e ?leo de canela na conserva??o p?s-colheita de tomate cereja / Use of cassava starch film and cinnamon oil in postharvest conservation of cherry tomato

OLIVEIRA, Cristiana Maia de 23 July 2013 (has links)
Submitted by Jorge Silva (jorgelmsilva@ufrrj.br) on 2018-11-12T20:55:15Z No. of bitstreams: 1 2013 - Cristiana Maia de Oliveira.pdf: 2253824 bytes, checksum: 0c49afa03412e03e8ba8d8d9e8b01029 (MD5) / Made available in DSpace on 2018-11-12T20:55:15Z (GMT). No. of bitstreams: 1 2013 - Cristiana Maia de Oliveira.pdf: 2253824 bytes, checksum: 0c49afa03412e03e8ba8d8d9e8b01029 (MD5) Previous issue date: 2013-07-23 / CNPq / The tomato has been widely cultivated in the state of Rio de Janeiro mainly by smallholders and family farmers that make use of organic agriculture as a way to add value to the culture. After harvest, the tomato presents itself as a highly perishable fruit, being a climacteric fruit, the ripening involves a number of changes in it physical and chemical characteristics. The main goal of this work was to evaluate the conservation and postharvest quality of cherry tomatoes Perinha ?gua Branca and Mascot cultivars, stored at room and controlled conditions. Three experiments were carried out: 1) postharvest longevity of fruits cherry tomato, 2) evaluation of the effect of cassava starch film on postharvest quality of fruits and 3) use of cinnamon essential oil to control pathogens. We carried out the following physico-chemical analyzes: weight loss, color, pH, titratable acidity, soluble solids, ascorbic acid and pectin methyl esterase activity. In the first experiment, we used fruits in the intermediate, pinky, red and mature stages to both cultivars. At room temperature, the post-harvest longevity of fruits in Perinha cultivar was 20 days in the pinky and 15 days to red and mature stages. ?Mascot? longevity was 24 days to the intermediate stage, 20 days for pinky and 15 days to red and mature stage. In controlled temperature postharvest longevity of fruits in Perinha cultivar was 24 days in the intermediate and pinky stages, 20 days to red and 15 days to mature. ?Mascot? longevity was 27 days in the intermediate and pinky stages, 24 days to red and to mature. In the second experiment, was used cassava starch coating in the following concentrations: 1%, 3% and 5%. It was observed that at room and controlled conditions cassava starch coating at a concentration of 3% promoted the best results, delaying the ripening and senescence while maintaining fruit quality. The concentration of 1% was similar to the control almost all the experimental period, while starch coating at 5% prevented the normal maturation process and showed high levels of infected fruits by fungi which affect the appearance and quality. The average activity of PME was higher in ?Mascot? fruits. The third experiment consisted in a combination of distilled water and starch coating at 3% associated with 0.1% and 0.3% concentrations of cinnamon essential oil. The cinnamon essential oil made changes on the fruit surface, causing stains and burns affecting the fruit quality. The oil was not effective in diseases control. / O tomate cereja vem sendo amplamente cultivado no Estado do Rio de Janeiro principalmente por pequenos produtores e pela agricultura familiar que fazem uso da agricultura org?nica como forma de agregar valor a cultura. O tomate ap?s a colheita apresenta-se como um fruto altamente perec?vel, sendo um fruto climat?rico seu amadurecimento acarreta uma s?rie de transforma??es em suas caracter?sticas f?sicas e qu?micas. Este trabalho teve por objetivo avaliar a conserva??o e qualidade p?s-colheita de tomates cereja cultivares Perinha ?gua Branca e Mascot, armazenados em condi??es ambiente e controlada. Foram realizados tr?s experimentos: 1) longevidade p?s-colheita de frutos de tomate cereja; 2) Avalia??o do efeito da pel?cula de f?cula de mandioca na qualidade p?s-colheita e 3) utiliza??o de ?leo essencial de casca de canela no controle de podrid?es. Foram realizadas as seguintes an?lises f?sicas e qu?micas: perda de massa fresca, cor, pH, acidez total titul?vel, s?lidos sol?veis, ?cido asc?rbico e atividade de pectinametilesterase. No experimento 1 foram utilizados frutos nos est?dios de vez, rosado, vermelho e maduro de ambas as cultivares. Em ambiente controlado, a longevidade p?s-colheita dos frutos da cultivar Perinha foi de 20 dias para os est?dios de vez e rosado e 15 dias para vermelho e maduro. Para ?Mascot? a longevidade foi de 24 dias para o est?dio de vez, 20 dias para rosado e 15 dias para vermelho e maduro. Em temperatura controlada, a longevidade p?s-colheita dos frutos da cultivar Perinha foi de 24 dias para de vez e rosado, 20 dias para vermelho e 15 dias para maduro. Para ?Mascot? a longevidade foi de 27 dias para de vez e rosado e 24 dias para vermelho e maduro. No experimento 2 foram utilizados revestimentos de f?cula de mandioca nas concentra??es de 1%, 3% e 5%. Foi observado que em condi??es ambiente e controlada, o revestimento de f?cula de mandioca na concentra??o de 3% foi o que promoveu melhores resultados retardando o processo de amadurecimento e senesc?ncia al?m de manter a qualidade dos frutos. A concentra??o de 1% se assemelhou ao controle durante quase todo per?odo experimental, enquanto que f?cula 5% impediu o processo normal de amadurecimento e mostrou alto ?ndice de frutos infectados por fungos comprometendo a apar?ncia e qualidade. A atividade m?dia de PME foi maior nos frutos de ?Mascot?. O experimento 3 consistiu da combina??o ?gua destilada e f?cula 3% associada a concentra??es de 0,1% e 0,3% de ?leo essencial de canela. O ?leo essencial de casca de canela promoveu altera??es na superf?cie dos frutos, provocando manchas e queimaduras afetando sua qualidade. O ?leo n?o foi efetivo no controle de podrid?es.
334

Qualidade de frutos e produtividade de tomateiro enxertado /

Maggio, Marcos Aurélio January 2018 (has links)
Orientador: Leila Trevisan Braz / Resumo: O tomateiro é amplamente cultivado em todas as regiões geográficas do Brasil, destacando-se como a segunda hortaliça mais cultivada, superada apenas pela batata em importância econômica. O uso da enxertia vem sendo realizado para esta cultura em muitos países, e suas contribuições são no controle de doenças, principalmente as de solo, mas também na absorção de nutrientes, estresse hídrico, salinidade, caraterísticas de qualidade do fruto, bem como na produtividade. Diante do exposto, o objetivo deste estudo foi avaliar o desempenho de três porta-enxertos (502271, ‘Shincheonggang’ e ‘Enpower’) e dois enxertos (‘Paronnty’ e ‘Ozone’), além da autoenxertia e pé-franco, quanto aos teores nutricionais da parte aérea da planta, qualidade dos frutos e produção. A avaliação foi realizada em dois experimentos realizados na Estação Experimental da Syngenta em Holambra – SP, nos anos de 2017 e 2018, utilizando delineamento em blocos ao acaso, com 10 tratamentos e quatro repetições. A partir dos dados obtidos, foram realizadas análises estatísticas individuais e conjuntas e as médias comparadas pelo teste de Tukey, a 5% de probabilidade. Para a maioria dos nutrientes, a enxertia proporcionou maiores teores que as plantas não enxertadas. Além disso, apresentaram melhorias para as características de qualidade, além de maior massa de frutos, sendo assim mais rentáveis para algumas combinações de tratamento. O uso em duas épocas de avaliação foi útil, uma vez que a maioria das características... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: Tomatoes are widely cultivated in all geographical regions of Brazil, standing out as the second most cultivated vegetable, surpassed only by potatoes in economic importance. The use of grafting has been carried out for this crop in many countries, and its contributions are to the control of diseases, mainly soil diseases, but also to nutrient absorption, water stress, salinity, fruit quality characteristics, as well as productivity. In view of the above, the purpose of this study was to evaluate the performance of three rootstocks (502271, 'Shincheonggang' and 'Enpower') and two grafts ('Paronnty' and 'Ozone'), as well as self-grafting and non-grafted plants as for the nutritional content in the aerial part of the plant, fruit quality and production. The evaluation was carried out in two experiments conducted at Syngenta Experimental Station in Holambra - SP, in the years 2017 and 2018, using a randomized complete block design with 10 treatments and four replications. From data obtained, individual and joint statistical analyzes were performed and the averages were compared by the Tukey’s test, at 5% probability. For most of the nutrients, grafting provided higher content than ungrafted plants. Moreover, they showed improvements to quality characteristics, in addition to greater fruit mass, thus being more profitable for some combinations of treatment. The use in two evaluation periods was useful, since most of the characteristics were influenced in the interaction years of ... (Complete abstract click electronic access below) / Doutor
335

The effects of irrigation and nitrogen on productivity, marketable yield and [supercript 1]H-NMR based metabolic profiling of African nightshade (Solanum retroflexum)

Masemola, Makhutse Clive 09 1900 (has links)
Efficient agronomic practices are vital for achieving sustainable management of water resources and N for producing highly nutritious leafy vegetables to curb malnutrition and poverty. The importance of proper N and irrigation of sustainable crop production is well recognised in literature, although irrigation and N application rate guidelines for ALV’s might not be sufficient for advisory purposes, especially for smallholder and commercial farmers. The limited access is attributed by factors such as the lack of commercialisation as a result of limited agronomic information describing optimum management options for S. retroflexum. Availability of such information would contribute to successful commercialisation of this crop. The primary objective of this study was to establish optimum agronomic management practices for S. retroflexum for smallholder farmer as well as commercial production in South Africa. This project consists of three main components with the overall objective to evaluate agronomic management practices of irrigation and N application on the marketable yield, nutritional water productivity and 1H-NMR metabolic profiling under a rainshelter. The results suggested that S. retroflexum responded positively to N application rates until an optimum marketable yield was obtained at 150 kg N·ha-1 with I66%FC, followed by the I100%FC with 150 kg N·ha-1,while, the lowest biomass was recorded in the I33%FC irrespective of the N application rate. This also indicates of how S. retroflexum is affected by insufficient irrigation, even at sufficient N application rates. N and irrigation are key factors limiting plant survival and growth and low applications has adverse effects on the marketable yield of S. retroflexum. Dry matter production increased with the higher N application and a linear increase was observed with N application having a significant effect on the dry matter production. Maximum irrigation use efficiency (IUE), was obtained in the moderately irrigated treatment (I66%FC) and the 150 kg N·ha-1, followed by the I100%FC and 150 kg N·ha-1. The stressed irrigation and N treatments showed sustainably low irrigation use efficiency as compared to the well irrigated treatment. This suggests the competitive capacity of S. retroflexum roots to draw water from deeper parts of the soil profile, during stressed conditions to maintain the turgor pressure, indicating that production of S. retroflexum is possible in arid areas where water could be a limiting input, but might not be profitable for farmers. However, the biomass yields obtained under the less irrigated soil water conditions may lack the quality needed to market the produce. The NWP for Zn and Fe showed significant differences among the irrigation and N treatments. Although the NWP of Mg in S. retroflexum was neither influenced by irrigation nor N application, with no statistical differences between the irrigation and N application observed. Among the different irrigation and N treatments evaluated, I33%FC obtained the lowest NWP irrespective of the N application rate, followed by I100%FC. The NWP increased linearly with an increase in N application. Optimum Fe NWP was obtained with 150 kg N ha-1, but declined significantly at application 225 kg N ha-1 in I33%FC and I100%FC. Maximum Fe NWP was obtained with I66%FC with 150 kg N ha-1. The NWP Fe for S. retroflexum in this study, are acceptable when compared to those obtained in literature. Therefore a significant interaction between N and irrigation application exist, with respect to Fe and Zn availability of S. retroflexum, which could be ideal for Fe and Zn malnutrition alleviation in resource poor households. 1H-NMR based metabolomic profiling was utilized for compound annotation as effected by irrigation and N. Chlorogenic acid, proline, sucrose and trigonelline were associated with separation in the irrigation treatments. Since no separation of the irrigation or N treatments was observed with the PCA, an OPLS-DA plot was constructed. A pairwise comparison of the I33%FC and I100%FC samples was done, which provided better separation between the clusters for the first harvest. Even better separations were observed with a pairwise OPLSDA analysis of the I33%FC and I100%FC samples for the second harvest. Primary metabolites such as sucrose, and proline and secondary metabolites trigonelline and chlorogenic acid were responsible for grouping of the stressed irrigation treatment as compared to the well irrigated treatment. Main findings of the study suggest that S. retroflexum is highly nutritious in Fe, Zn and Mg, which might play a significant role in malnutrition alleviation. Solanum retroflexum requires sufficient soil water content, for achieving high nutrient yield and nutritional water productivity. The results clearly illustrate that the perception that S. retroflexum grow well on low soil fertility mostly practised in rural and smallholder farming is incorrect and misleading. Moreover, S. retroflexum can be an ideal cropping system for smallholder and commercial farmers in water scarce areas such as South Africa, although marketable yield is severely affected. / Agriculture and  Animal Health / M. Sc. (Agriculture)
336

Breeding for Tomato Resistance to Spider Mite <em>Tetranychus urticae</em> Koch (Acari: Tetranychidae)

AL-Bayati, Ammar Sami 01 January 2019 (has links)
Cultivated tomato plants are extremely susceptible to the two-spotted spider mite Tetranychus urticae Koch. Selection for pest resistance is usually a crucial step required to achieve successful genetic resistance transfer from wild into cultivated tomato genotypes. S. habrochaites LA2329, a wild relative of tomato, is highly resistant to arthropods. Its resistance has been attributed to the presence of a high density of type IV and type VI trichomes and abundant production of 7-epi-zingiberene, a sesquiterpene hydrocarbon. The interspecific backcross hybrids used in this research were derived from the cross between the wild relative tomato, S. habrochaites LA2329, and the cultivated tomato, S. lycopersicum ‘Zaofen 2’ (ZH2). This population has been directly selected for type IV trichome density and zingiberene. The arthropod resistance status of the backcross hybrids was unknown when this research was initiated. Thus, the main objective of the research was to verify the transfer of arthropod resistance from S. habrochaites to cultivated tomato. The effects of glandular trichome densities and leaf zingiberene contents on spider mite behavior and biology were also explored. Also, the chemical composition of the trichome secretions in the wild tomato donor is segregating for presence and abundance of sesquiterpenoids related to zingiberene. The bioactivity of these sesquiterpenoids was explored in this research. To evaluate the relative bioactivities of zingiberene alcohol and 7-epizingiberene, extracted from glandular trichomes of Solanum habrochaites accession LA2329, as well as alpha-zingiberene obtained from ginger oil, these were purified by silica gel chromatography and bioassayed with two-spotted spider mites, Tetranychus urticae Koch (Acari: Tetranychidae) using a bean leaf disc bioassay. Zingiberene alcohol was most efficacious and alpha-zingiberene, was least efficacious, while the efficacy of 7-epizingiberene was intermediate. Thus, tomato breeders should consider introgression of the genes responsible for the oxidation of 7-epizingiberene into zingiberene alcohol to potentially improve the spider mite resistance of cultivated tomato. Also, it is possible that this compound may be exploited as eco-biopesticide approach for integrated pest management against a broad spectrum of herbivorous pests. To verify transfer of arthropod resistance, a bioassay utilizing whole leaves was employed. Nine hybrids (BC3F3 and BC3F4) were chosen for this bioassay, based on variation of type IV trichome density and zingiberene concentration among the hybrids. The experiment also included three susceptible and three resistant control plants. Mite responses on some of the hybrids were similar to those on the resistant wild donor parent, S. habrochaites, as indicated by number of leaflet surfaces infested by mites, degree of mite webbing and feeding damage. Egg density on four backcross hybrids was similar to that on the S. habrochaites resistant controls. Based these results, we concluded that resistance had been successfully transferred from the wild accessions to the hybrids by deployment of backcrossing and indirect selection. There was a significant negative correlation of almost all mite behavioral and biological responses with Type IV trichome density and zingiberene content. This bioassay illuminated behavioral variations of mites associated with presence or absence of leaf compounds and glandular trichome densities. Also, the results support the idea that introgression of type IV trichomes and zingiberene has led to effective spider mite resistance. In another bioassay-based experiment to verify transfer of resistance, seven interspecific backcross hybrids (BC3F2), the resistant parent LA2329, and two susceptible cultivated tomato lines, the recurrent parent ZH2 and ‘Small Roma’, were used in thumbtack bioassays. Mite movement was measured by imaging bioassayed leaves at 15, 20, 30, 45, and 60 min intervals. In addition to confirming transfer of spider mite resistance, other objectives included determination of the relative contributions of type IV and VI trichome densities and leaf compounds to mite behavior over time intervals. Our findings confirmed the transfer of mite repellency from the wild resistant parent to advanced backcross hybrids. Several backcross hybrids performed similarly to the wild donor parent, displaying shorter distances traveled on the leaves after 15 and 30 min. The type IV and type VI trichome densities as well as zingiberene contents had a significant positive correlation with the number of spider mites remaining on tack. There was a significant negative correlation of type IV density and zingiberene concentration with the total distance travelled by mites for both the abaxial and adaxial surfaces across most time intervals. Stepwise multiple regression analysis showed that the type IV trichome density was the most critical factor, and zingiberene content was a secondary factor across over most time intervals. T. urticae remained longer on the thumbtack heads and traveled shorter distances on the leaf surface of the wild donor parent LA2329 and the interspecific hybrids compared to S. lycopersicum leaves. These results indicated that introgression of genetic resistance, especially repellence, against spider mite from the wild relative into cultivated tomato varieties has been successfully achieved. In conclusion, trichome type IV and/or zingiberene content has been successfully transferred from the wild relative into interspecific tomato hybrids, and the hybrids show significant adverse impact on spider mite behavior and/or biology in whole leaf and thumbtack bioassays. Type IV trichome density is the most crucial factor in mite deterrence while zingiberene seemed to be a second key factor across most of time durations for both surfaces. Collectively, several backcross hybrids had similar leaf characteristics to the S. habrochaites LA2329, also may be a potential source of resistance to other insect pests.
337

Fungicidas de efeitos fisiológicos no metabolismo e na produtividade do tomateiro /

Rodrigues, Luan Fernando Ormond Sobreira January 2017 (has links)
Orientador: João Domingos Rodrigues / Resumo: O tomateiro é uma das mais importantes culturas no Brasil, sendo São Paulo o segundo estado que mais produz este vegetal no país, atrás apenas de Goiás. Além do efeito protetor e curativo dos fungicidas utilizados para este estudo, verificou-se que também têm efeito sobre a fotossíntese líquida da planta, devido à redução momentânea da respiração celular, processo fisiológico que compete com a fotossíntese. Dado o exposto, este estudo teve como objetivo determinar o efeito fisiológico de fungicidas sobre a atividade de enzimas antioxidantes, a fotossíntese e as características produtivas e de viabilidade econômica do tomateiro 'saladete', híbrido Caribe F1 cultivado em casa de vegetação. O experimento foi conduzido na Fazenda de Ensino, Pesquisa e Produção de São Manuel-SP, pertencente à FCA/UNESP. Utilizou-se o delineamento experimental de blocos casualizados, com oito tratamentos e quatro repetições, cada unidade experimental contendo sete plantas. Os tratamentos referem-se ao uso de fungicidas com efeitos fisiológicos, nomeadamente: T1 – Controle; T2 – Piraclostrobina (CT); T3 – CT+BOS; T4 – Boscalida (BOS); T5 – BOS+FP; T6 – Fluxapiroxade+Piraclostrobina (FP); T7 – FP+CT e T8 – FP+CT+BOS. Foram realizados cinco testes de quantificação de trocas gasosas, realizando-se essas análises em diferentes momentos após a pulverização dos fungicidas. Como resultados foi possível observar que os fungicidas de efeitos fisiológicos aplicados nessa pesquisa influenciam positivamente nas... (Resumo completo, clicar acesso eletrônico abaixo) / Doutor
338

Cálcio e sinalização do restabelecimento vegetal após estresse mecânico

Campos, Felipe Girotto January 2019 (has links)
Orientador: Carmen Sílvia Fernandes Boaro / Resumo: Cálcio apresenta função estrutural, na parede celular, atua na manutenção da estabilidade da membrana plasmática e é mensageiro secundário, envolvido na regulação de processos fisiológicos do desenvolvimento e em respostas a estresses. No dano mecânico, espécies reativas de oxigênio (ERO) auxiliam no afrouxamento da parede celular e na abertura de canais de Ca2+ do reticulo endoplasmático e o aumento de Ca2+ no citoplasma gera uma cascata de sinais mediados por hormônios, ERO, peroxidases e cálcio-calmodulina. Além disso, o Ca2+ é de fundamental importância para o funcionamento do fotossistema II (PSII), uma vez que, sua variação pode interferir na cadeia transportadora de elétrons. O objetivo deste estudo foi investigar a influência da variação de cálcio na sinalização de defesa de plantas de crescimento lento e rápido e submetidas a dano mecânico. O delineamento experimental foi em blocos casualizados, com quatro repetições, em esquema fatorial, onde as plantas foram cultivadas com 0, 2 e 4 mM de Ca2+, com e sem dano mecânico e cinco épocas de avaliação, realizadas aos 0, 15, 30, 60 e 90 dias após o dano mecânico. Com a espécie de crescimento lento, Annona emarginata, foram estudados fotossíntese (fluorescência da clorofila a e trocas gasosas), massa seca total, crescimento quantitativo e peroxidação lipídica. No Solanum lycopersicum Micro-Tom, espécie de crescimento rápido, expressão de genes de estresses, enzimas antioxidantes, peroxido de hidrogênio, peroxidação lipídica... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: Calcium presents structural function in the cell wall, it acts in the maintenance of the stability of the plasma membrane and is secondary messenger, involved in the regulation of physiological processes of development and in responses to stresses. In mechanical damage, reactive oxygen species (ROS) assist in the loosening of the cell wall and in the opening of Ca2+ channels of the endoplasmic reticulum, and the increase of Ca2+ in the cytoplasm generates a cascade of signals mediated by hormones, ROS, peroxidases and calcium-calmodulin. In addition, Ca2+ is of fundamental importance for the functioning of photosystem II (PSII), since its variation can interfere with the electron transport chain. The objective of this study was to investigate the influence of calcium variation on defense signaling of slow and fast growing plants and submitted to mechanical damage. The experimental design was a randomized block, with four replications in a factorial design, where the plants were cultured with 0, 2 and 4 mM Ca2+ with and without mechanical damage five evaluation times were made at 0, 15, 30, 60 and 90 days after mechanical damage. With the slow-growing species, Annona emarginata, photosynthesis (chlorophyll a fluorescence and gas exchange), total dry mass, quantitative growth and lipid peroxidation were studied. The results allowed to conclude that the Annona emarginata plants presented greater resistance to the mechanical damage in the presence of calcium and were more sensiti... (Complete abstract click electronic access below) / Doutor
339

Formation and Control of Chlorophyll and Solanine in Tubers of Solanum Tuberosum, L. and Evaluation of Solanine Toxicity

Patil, Bhaskarrao C. 01 May 1972 (has links)
Chlorophyll and solanine syntheses as influenced by cultivars, specific gravities, light intensities, and duration of exposure to light were studied in potato (Solanum tuberosum, L.) tubers. Chemicals, gamma radiation, clear polyethylene packaging in 15 per cent co 2 , and storage at subatmospheric pressure were employed to control the formation of these two compounds. The toxicity of solanine to mice, the fungus Trichoderma viride, and cholinesterase inhibition patterns in rabbits and a dog were evaluated. The influence of the central nervous system stimulating drugs was investigated to find if they counteracted solanine toxicity. Of the 11 cultivars tested, tubers of Bounty, Kennebec, Nor chip, and Red Lasoda were most sensitive to greening and solanine development. LaChipper and Platte tubers were least susceptible to greening and their solanine contents were minimum. The significant differences in chlorophyll and solanine formation among cultivars showed that greening potential is a cultivar characteristic. xi Chlorophyll development in tubers was inversely related to their specific gravity. Solanine synthesis was, however, not dependent on specific gravity. Studies on effect of four light intensities on Kennebec potato tubers that were stored for nearly 6 months showed that more chlorophyll formed at 100 and 150 ft-c than at 50 and 200 ft-c light intensities. Generally, chlorophyll formation increased with increased light intensity up to 100 ft-c, slowly and steadily declined up to 150 ft-c, and sharply declined at 200 ft-c. There were no significant differences in the solanine contents of the tubers after exposure to these light intensities. The duration of exposure of the tubers to 100 ft-c revealed that solanine and chlorophyll contents increased linearly with the duration of exposure up to the sixth and tenth day, respectively. There was no difference in the amount of chlorophyll formed at the end of the tenth and fifteenth day. The solanine contents were rather constant from the sixth to the tenth day and then slightly declined at the end of the fifteenth day. The respiration of the tubers did not seem to have an apparent relationship to solanine and chlorophyll formation. Investigation on the control of greening showed that two chemicals, Ethrel (2-chloroethylphosphonic acid) and Alar (succinamic acid, 2, 2-dimethylhydrazide) when applied at 10, 000 ppm by vacuum injection technique, were significantly effective in inhibiting chlorophyll and solanine syntheses. Ethrel was most effective in controlling the chlorophyll formation and the least solanine xii was formed after the Alar treatment. The dose of 10 krads of gamma radiation inhibited 80 per cent, while polyethylene packaging with 15 per cent co 2 , only 32 per cent of chlorophyll synthesis. Storage of tubers at subatmospheric pressure of 126 mm-Hg resulted in complete inhibition of chlorophyll formation. The irradiation, co 2 environment either alone or in combination, and subatmospheric pressure treatments did not affect solanine synthesis. Solanine was toxic to mice, rabbits, a dog, and the fungus Trichoderma viride. The LD 50 for intraperitoneal (ip) administration, single dose, in mice was 32. 3 mg of solanine per Kg body weight, the 19/20 confidence limits being 27. 6 - 37. 9 mg. Plasma and erythrocytic cholinesterase inhibition in rabbits indicated that solanine was a weak to moderate inhibitor of both specific and nonspecific cholinesterase. There was less inhibition of erythrocytic cholinesterase than that of plasma in vivo. In an anesthetized dog, cumulative doses of solanine showed a quick inhibition of cholinesterase but rapid recovery · was noted in the case of serum enzyme, while there was no inhibition of the red cell enzyme. A prior intraperitoneal dose of 2 mg/Kg of atropine sulfate lowered the mortality after ip injection into mice at 40 mg/Kg of solanine from 9/10 to 5/10. Similar application of pargyline (5 mg/Kg ip) and amphetamine (5 mg/Kg ip) had no effect on mortality from solanine. Atropine influence appeared antagonistic and counteracted solanine toxicity. The concentration of 10 mg of solanine per 100 ml of potato-dextroseagar medium had no effect on the Trichoderma viride fungus growth, while at a concentration of 200 mg, the growth ceased. The (Lethal Concentration) Lc 50 was 102. 2 mg/100 ml, and 19/20 confidence limits being 83. 85 - 124. 6 mg.
340

Efecto de la aplicación de ácido giberélico y benciladenina sobre la cuaja y producción de tomate injertado bajo invernadero frío / Effect of gibberellic acid and benzyladenine aplication on fruitset and production of grafted tomato plants under cold greenhouse

Pizarro Correa, Juan Pablo Ernesto January 2014 (has links)
Memoria para optar al título profesional de Ingeniero Agrónomo / El tomate (Solanum lycopersicum L.) ocupa el primer lugar dentro de las hortalizas demandadas en Chile. El alto consumo nacional obliga a los productores a mantener una alta oferta, prácticamente, de forma constante durante todo el año. Las condiciones desfavorables para la producción de tomate fresco (principalmente asociadas a rangos de temperatura y humedad no óptimas en el proceso de fecundación), exige disponer de estrategias agronómicas que logren sobrellevar las circunstancias desfavorables, frecuentemente registradas en invernaderos. Para el cultivo del tomate se han reportado efectos satisfactorios sobre la retención de frutos y la productividad con aplicaciones de reguladores de crecimiento. Sin embargo, la falta de información en torno al momento, la concentración y la forma de aplicación, ha generado incertidumbre sobre los potenciales beneficios. El objetivo de este ensayo fue determinar el efecto de la aplicación de benciladenina (BA) y ácido giberélico (GA3) sobre la retención de frutos y productividad en plantas de tomate. En un invernadero frío, bajo malla antiáfido, durante la temporada 2012-2013, se llevó a cabo un ensayo en la Facultad de Ciencias Agronómicas de la Universidad de Chile, La Pintana, Santiago. Se utilizaron plantas de tomate cv. Fiorentino injertados sobre patrón Emperador. Las concentraciones evaluadas fueron: 15 mg L−1 de BA, 10 mg L−1 de GA3 y la combinación de ambos reguladores de crecimiento. Las aplicaciones se realizaron a cada inflorescencia, en dos momentos fenológicos: botón floral cerrado y caída de pétalos. Las variables analizadas fueron número de flores y frutos por racimo, retención de frutos, masa media de frutos, diámetro polar y ecuatorial de frutos, número de semillas por fruto y largo de raquis. Las evaluaciones se realizaron en los primeros cuatro pisos productivos. No hubo efecto de interacción de los factores GA3 y BA para ninguna de las variables analizadas. La aplicación de 10 mg L−1 de GA3 redujo la producción, la masa media de frutos y el número de semillas por fruto. Sin embargo, este fitorregulador aumentó la longitud del raquis. Por otra parte, la aplicación de 15 mg L−1 de BA indujo un alto porcentaje de frutos de mayor calibre y redujo el número de los de menor tamaño. Se propone estudiar el efecto de concentraciones superiores. / Tomato fruit (Solanum lycopersicum L.) take the first place of the vegetables demand in Chile. The high national fruits consumption, require growers to support an elevated offer, practically, throughout the whole year. The unfavorable conditions for tomato production (mainly associated with non optimum temperature and moisture range in the fecundation process), require agronomy strategies to support adverse circumstances, registered frequently under greenhouse conditions. There have been suitable effects reported for tomato culture on fruit set and productivity with applications of growth regulators, however, the lack of time, concentration and optimum application procedure documentation has raised uncertainty of the real benefits. The aim was to determine the effect of benziladenine (BA) and gibberellic acid (GA3) application, on fruit set and production in tomato plants. A greenhouse experiment was develop, with cv. Fiorentino tomatoes grafted in Emperador rootstock plants, during 2012-2013 season, in the Faculty of Agricultural Sciences of the University of Chile, La Pintana, Santiago. Applications of 15 mg L−1 of BA, 10 mg L−1 of GA3, and a mixture of both growth regulators were tested. Each inflorescence was applied in two phenological stages: close flower bud and fallen corolla. The number of flowers and fruits per cluster, fruit set, average mass fruits, polar and equatorial diameter per fruit, seed number per fruit and rachis length were evaluated on the first four production floors. There was no interaction between GA3 and BA factors at any of the studied variables. The application of GA3 10 mg L−1 reduced production, fresh fruit mass and seed number per fruit, however, it increased the rachis length. Moreover, the application of BA 15 mg L−1 increased the high caliber fruit percentage and reduced the small sized fruit. The application of both growth regulators did not increase neither fruit size or the production. It is suggested to continue studying the effects of higher concentrations.

Page generated in 0.0595 seconds