Made available in DSpace on 2015-08-20T17:10:07Z (GMT). No. of bitstreams: 0 Previous issue date: 2015-03-30. Added 1 bitstream(s) on 2015-08-20T17:27:01Z : No. of bitstreams: 1 000844621.pdf: 1255228 bytes, checksum: 98151853c54471172f5b1bca62465aa1 (MD5) / A melancia (Citrullus lanatus) é considerada uma das cucurbitáceas mais importantes no mundo e o Brasil é o quarto maior produtor, com área total cultivada de 90.000 ha e produção média de cerca de dois milhões de toneladas. No Brasil, há várias espécies de vírus descritas em melancia pertencentes ao gênero Potyvirus, Cucumovirus, sendo Zucchini lethal chlorosis virus a única espécie até então relatada no gênero Tospovirus. Considerando a alta incidência de plantas de melancia exibindo sintomas causados por vírus durante as safras 2012/2013 e a presença de tripes no campo, este trabalho teve como objetivo a identificação e caracterização do vírus e do vetor associado a sua transmissão. No primeiro capítulo intitulado Citrullus lanatus is a new natural host of Groundnut ringspot virus in Brazil, foi relatada a ocorrência de Groundnut ringspot virus (GRSV) em melancia ocasionando mosaico, deformações e lesões necróticas em folhas e manchas necróticas nos frutos. O GRSV foi coletado durante os anos de 2012 e 2013 nas regiões produtoras dos municípios de Presidente Prudente e Marília. O isolado de GRSV de melancia apresentou um círculo de hospedeiros semelhante aos isolados de GRSV provenientes de solanáceas, com a excessão de não infectar tomateiro cv. Santa Clara e Mariana. Espécimes de tripes coletados no campo foram capazes de transmitir o GRSV para melancia, pimentão e espécies de Nicotiana. Este foi o primeiro relato de infecção natural de melancia por GRSV. No segundo capítulo intitulado A Taqman real-time RT - PCR assay for detection of Groundnut ringspot virus foi possível detectar o GRSV por PCR quantitativo (qPCR) em amostras de melancia e em tripes individuais coletados no campo. A detecção do GRSV por qPCR poderá servir como uma ferramenta útil nos ... / Watermelon (Citrullus lanatus) is considered one of the most important cucurbits in the world and Brazil is the fourth largest producer, with a total cultivated area of 90.000 ha and average production of about two million tons. In Brazil, viruses described in watermelon belong to the genus Potyvirus and Cucumovirus and Zucchini lethal chlorosis virus is the only species of Tospovirus genre described on this culture. Considering the high incidence of watermelon plants showing symptoms caused by virus during the 2012/2013 seasons and the presence of thrips in the field, the virus and the vector associated with the disease was identified and characterized. In the first chapter entitled Citrullus lanatus is a new natural host of Groundnut ringspot virus in Brazil, the species of tospovirus Groundnut ringspot virus(GRSV) was reported causing mosaic, deformation and necrotic lesions on leaves and fruits of watermelon. The GRSV was collected during the years 2012 and 2013 in producing areas of Presidente Prudente and Marília. GRSV from watermelon, differently from GRSV strains found on solanaceas, didn't infected tomato plants cv. Santa Clara and Mariana. Thrips specimens collected in the field were able to transmit GRSV to watermelon, peppers and Nicotiana species. This was the first report of natural infection of watermelon by GRSV. In the second chapter entitled A Taqman real-time RT - PCR assay for detection of Groundnut ringspot virus a quantitative PCR test was developed to efficiently detect GRSV from watermelon and from individual thrips. The test might be useful to detect GRSV and for further studies with this virus. The third chapter Efficient detection of Frankliniella schultzei (Thripidae: Thysanoptera) by real-time PCR reports the efficient detection of Frankliniella schultzei by the analysis of the mitochondrial gene cytochrome oxidase I (mtCOI). Thrips samples were ...

Orientador: Renate Krause Sakate / Coorientadora: Kelly Cristina Gonçalves Rocha / Banca: Marcelo Agenor Pavan / Banca: Nobuyoshi Narita / Banca: Jorge Alberto Marques Rezende / Banca: Tatiana Mituti / Resumo: A melancia (Citrullus lanatus) é considerada uma das cucurbitáceas mais importantes no mundo e o Brasil é o quarto maior produtor, com área total cultivada de 90.000 ha e produção média de cerca de dois milhões de toneladas. No Brasil, há várias espécies de vírus descritas em melancia pertencentes ao gênero Potyvirus, Cucumovirus, sendo Zucchini lethal chlorosis virus a única espécie até então relatada no gênero Tospovirus. Considerando a alta incidência de plantas de melancia exibindo sintomas causados por vírus durante as safras 2012/2013 e a presença de tripes no campo, este trabalho teve como objetivo a identificação e caracterização do vírus e do vetor associado a sua transmissão. No primeiro capítulo intitulado "Citrullus lanatus is a new natural host of Groundnut ringspot virus in Brazil", foi relatada a ocorrência de Groundnut ringspot virus (GRSV) em melancia ocasionando mosaico, deformações e lesões necróticas em folhas e manchas necróticas nos frutos. O GRSV foi coletado durante os anos de 2012 e 2013 nas regiões produtoras dos municípios de Presidente Prudente e Marília. O isolado de GRSV de melancia apresentou um círculo de hospedeiros semelhante aos isolados de GRSV provenientes de solanáceas, com a excessão de não infectar tomateiro cv. Santa Clara e Mariana. Espécimes de tripes coletados no campo foram capazes de transmitir o GRSV para melancia, pimentão e espécies de Nicotiana. Este foi o primeiro relato de infecção natural de melancia por GRSV. No segundo capítulo intitulado "A Taqman real-time RT - PCR assay for detection of Groundnut ringspot virus" foi possível detectar o GRSV por PCR quantitativo (qPCR) em amostras de melancia e em tripes individuais coletados no campo. A detecção do GRSV por qPCR poderá servir como uma ferramenta útil nos ... / Abstract: Watermelon (Citrullus lanatus) is considered one of the most important cucurbits in the world and Brazil is the fourth largest producer, with a total cultivated area of 90.000 ha and average production of about two million tons. In Brazil, viruses described in watermelon belong to the genus Potyvirus and Cucumovirus and Zucchini lethal chlorosis virus is the only species of Tospovirus genre described on this culture. Considering the high incidence of watermelon plants showing symptoms caused by virus during the 2012/2013 seasons and the presence of thrips in the field, the virus and the vector associated with the disease was identified and characterized. In the first chapter entitled "Citrullus lanatus is a new natural host of Groundnut ringspot virus in Brazil", the species of tospovirus Groundnut ringspot virus(GRSV) was reported causing mosaic, deformation and necrotic lesions on leaves and fruits of watermelon. The GRSV was collected during the years 2012 and 2013 in producing areas of Presidente Prudente and Marília. GRSV from watermelon, differently from GRSV strains found on solanaceas, didn't infected tomato plants cv. Santa Clara and Mariana. Thrips specimens collected in the field were able to transmit GRSV to watermelon, peppers and Nicotiana species. This was the first report of natural infection of watermelon by GRSV. In the second chapter entitled "A Taqman real-time RT - PCR assay for detection of Groundnut ringspot virus" a quantitative PCR test was developed to efficiently detect GRSV from watermelon and from individual thrips. The test might be useful to detect GRSV and for further studies with this virus. The third chapter " Efficient detection of Frankliniella schultzei (Thripidae: Thysanoptera) by real-time PCR" reports the efficient detection of Frankliniella schultzei by the analysis of the mitochondrial gene cytochrome oxidase I (mtCOI). Thrips samples were ... / Doutor

Thesis (M.A. Agricultural Management (Plant Production)) -- University of Limpopo, 2017 / Nemafric-BL and Nemarioc-AL phytonematicides, which are being researched and developed to serve as alternatives to methyl bromide, have not been tested against plant growth and accumulation of essential nutrient elements in watermelon (Citrullus lanatus) cultivars. The objectives of this study were two fold, to determine the (1) overall growth responses and accumulation of selected essential nutrient elements in watermelon cultivars ‘Congo’ and ‘Charleston Gray’ and suppression of Meloidogyne javanica in response to increasing concentrations of Nemafric-BL and Nemarioc-AL phytonematicides, and (2) efficacy of Velum, Nemafric-BL and Nemarioc-AL phytonematicides on growth of watermelon, accumulation of selected essential nutrient elements in leaf tissues of cv. ‘Congo’ and the suppression of population densities of Meloidogyne species. Objective 1 and Objective 2 were achieved under greenhouse and field conditions, respectively. At 56 and 90 days after initiating the greenhouse and field treatments, respectively, the data were collected and subjected to statistical analyses. Nemafric-BL phytonematicide significantly affected growth of watermelon cultivars ‘Charleston Gray’ and ‘Congo’, whereas Nemarioc-AL phytonematicide did not have any significant effects on the plant variables of both cultivars. Generally, plant growth variables and increasing concentrations of Nemafric-BL phytonematicide had density-dependent growth (DDG) patterns, which were quantified through either positive or quadratic equations (Chapter 3). In contrast, both phytonematicides had significant effects on selected nutrient elements in leaf tissues of both watermelon cultivars. The affected nutrient elements, P, Mn and Na versus increasing concentrations of phytonematicides exhibited the DDG patterns, which were also quantified through either positive or quadratic equations (Chapter 3). The phytonematicides were consistent in suppressing nematode numbers in both watermelon cultivars. Comparison of synthetic nematicide Velum and the two phytonematicides under field conditions suggested that, relative to untreated control, the three products each stimulated growth of watermelon cv. ‘Congo’. The efficacy of Nemafric-BL and Nemarioc-AL phytonematicides on suppression of population densities of Meloidogyne species was comparable to that of Velum. In conclusion, Nemafric-BL and Nemarioc-BL phytonematicides were highly effective in managing population densities of Meloidogyne species in watermelon cultivars and also affected the partitioning of selected nutrient elements in tissues. The study provided essential information that could assist in decision-making in nematode management in watermelon production, particularly in fertiliser application.

MSCFST / Department of Food Science and Technology / Watermelon (Citrullus lanatus) juice is rich in phytochemicals that possess antioxidant properties which are known to have a positive contribution to human health. Colour, pH, total soluble solids, lycopene, β-carotene, ascorbic acid, total polyphenolic content and antioxidants activity are quality properties that characterise watermelon juice. However, these quality properties undergo some chemical changes throughout the stages of maturity of the fruit as well as during thermal processing. The aim of this study was to investigate the effects of maturity and filtration on the physicochemical properties (colour, pH, total soluble solids) and the phytochemicals (lycopene, β-carotene, ascorbic acid, total polyphenolic content and antioxidants activity) of fresh watermelon juice. It further investigated thermosonication effects on these quality properties using response surface methodology (RSM). RSM considering temperature (25 – 52ºC), time (2 – 10 min) and amplitude level (24.1 – 60 μm) at a constant frequency of 20 kHz were the independent variables while colour variables (L*, a* and b*, C* and h*), pH, total soluble solids, lycopene, β-carotene, ascorbic acid, total polyphenolic content and antioxidants activity were the dependent variables. Results showed that colour, pH, total soluble solids, lycopene, β-carotene, ascorbic acid, total polyphenolic content and antioxidants activity of watermelon fruit juice are maturity dependent. All the physicochemical and phytochemical properties increased with maturity. The combination of the CIELAB parameters (L*, a*, b*) was clearly explained by the Chroma (C*) and hue (hº). The (C*) and hº values of the watermelon fruit juice were significantly (p < 0.05) affected by the stages of maturity. The red colour was observed to be more saturated in the fully - ripe sample as indicated by the highest Chroma (7.35) values. The half - ripe sample which was observed to be pink - red had a C* of 5.88 while the lowest (4.32) value was observed from the unripe sample. The highest hº value was obtained from unripe sample (83.89), while lower value was observed from the fully - ripe (76.03) sample because of the saturation of the red colour in the fully - ripe sample. The total soluble solids also increased with stages of maturity 6.66 to 6.60 at half - ripe while at fully - ripe redness changed from 9.3 to 8.99 and TSS 8.37 to 8.02. Filtration has shown a significant (p < 0.05) on the C* and hº values. There was a higher retention of all dependent variables at lower thermosonication treatment (25ºC; 24.4 μm), especially the lycopene which increased by 127%. Model predictions for the colour properties and phytochemicals were closely correlated to the experimental results obtained. Prediction models were found to be significant (p < 0.05) with low standard errors and high coefficients of determination (R2). / NRF