No estado do Espírito Santo (ES), uma das principais áreas produtoras de mamão do país, a eliminação sistemática de plantas doentes tem sido aplicada desde a década de 1980 para o controle do mosaico do mamoeiro (Papaya ringspot virus - type P; PRSV-P). O uso permanente dessa prática nos últimos 25 anos levou a uma aparente seleção e predominância de isolados fracos do vírus. Os objetivos deste trabalho foram: investigar a prevalência desses isolados fracos, bem como a estabilidade e o efeito protetor contra isolados severos do vírus; estudar a infecção natural de abobrinha de moita (Cucurbita pepo cv. Caserta) e abóbora moranga (C. maxima cv. Exposição) com o PRSV-P quando plantadas ao lado de mamoeiros infectados e caracterizar um isolado do Alfalfa mosaic virus (AMV) em infecção natural em mamoeiro. A detecção de possíveis isolados fracos do vírus foi realizada por PTAELISA, microscopia eletrônica e RT-PCR. Todos os isolados também foram inoculados mecanicamente em mamoeiro cv. Golden para avaliação de sintomas. Sequências de nucleotídeos e de aminoácidos deduzidos do gene da proteína capsidial de alguns isolados fracos mostraram identidades superiores a 89% e 90%, respectivamente, com isolados do PRSV-P. De 119 amostras de mamoeiros analisadas, 86 estavam infectadas com o PRSV-P, mas somente 75 induziram sintomas fracos em mamoeiros. Quatro isolados fracos foram selecionados ao acaso para estudos de estabilidade, e de proteção em casa de vegetação. Apenas dois isolados fracos induziram sintomas estáveis em mamoeiros até a oitava transferência. A proteção total só foi obtida com plantas premunizadas com dois isolados fracos e desafiados com o isolado PRSV-PES. Plantas de mamoeiros cv. Golden premunizadas com vários isolados fracos do PRSV-P foram expostas em condições de campo na ESALQ/USP, Piracicaba, SP, em dois experimentos independentes. Poucas plantas permaneceram com sintomas fracos de mosaico até o final dos experimentos. Uma terceira exposição foi realizada em Linhares, ES, com mamoeiros cvs. Sunrise Solo e Golden premunizados com oito isolados fracos, coletados nos experimentos em campo na ESALQ/USP. Apenas uma planta premunizada com um isolado fraco permaneceu com sintomas leves da doença até a última avaliação. Tentativas de detectaçao de infecções naturais de cucurbitáceas com o PRSV-P foram realizados em dois plantios de abobrinha de moita e dois de abóbora moranga, na ESALQ/USP, Piracicaba, SP. A detecção do vírus foi feita por meio da inoculação de extratos foliares das cucurbitáceas em mamoeiros cv. Golden. Os mamoerios foram avaliados por meio de sintomas, PTA-ELISA e RT-PCR. Nenhuma planta de mamoeiro inoculada com extratos foliares das duas cucurbitáceas exibiu sintomas de mosaico, embora o gene ci, mas não o cp, tenha sido detectado em uma amostra de folhas de mamoeiro, indicando que ao menos uma planta de abobrinha de moita estava infectada. Finalmente, no decorrer dos ensaios de campo na ESALQ/USP, constatou-se uma planta de mamoeiro apresentando sintomas severos de mosaico amarelo, deformação foliar e necrose sistêmica, diferente daqueles induzidos pelo PRSV-P. Análises biológicas, sorológica e moleculares confirmaram tratar-se do AMV. Este é o primeiro relato de infecção natural de mamoeiro com esse vírus. / Papaya ringspot virus type P (PRSV-P) causes the major disease in Brazilian papaya orchards that result in significant yield losses. In Espírito Santo state systematic rouging of infected plants has been applied since early 1980s for the control of this disease. Its permanent use over the last 25 years has lead to an apparent selection and predominance of mild strains throughout papaya orchards. The objectives of this work were to investigate the prevalence of mild isolates, as well the stability and protective effect against severe isolates of the virus; The aim of this work was to study the natural infecction of zucchini squash (Cucurbita pepo cv. Caserta) and pumpkin (C. maxima cv. Exposição) grown near to papaya trees infected with PRSV-P and characterize an isolate of Alfalfa mosaic virus (AMV) in natural infection in papaya. The detection of possible mild isolates of the virus was performed by PTA-ELISA, electron microscopy and RT-PCR. All isolates were inoculated mechanically in papaya cv. Golden for symptoms evaluation. Nucleotides and deduced amino acids sequences of the coat protein gene of some mild isolates showed identities above 89% and 90%, respectively, with isolates of PRSV-P. Of 119 samples from papaya plants analyzed, 86 were infected with PRSV-P and 75 induced mild symptoms on papaya. Four mild isolates were randomly selected for stability and protection studies under greenhouse. Only two isolates induced mild symptoms on papaya and remained stables until the eighth transference. Full protection was obtained with preimmunized plants with two mild isolates and challenged with the isolate PRSV-P-ES. Plants of papaya cv. Golden preimmunized with several mild isolates of PRSV-P were exposed under field conditions at ESALQ/USP, Piracicaba,SP, in two independent experiments. Few plants remained with mild mosaic symptoms at the end of the experiments. A third field exposition was held in Linhares,ES, with papaya cvs. Golden and Sunrise Solo preimmunized with eight mild isolates, collected in field experiments at ESALQ/USP. Only one plant preimmunized with a mild isolate remained with mild symptoms of the disease until the last evaluation. Attempts of detection of natural infections of cucurbits with PRSV-P were carried out in two plantations of zucchini squash and pumpkin at ESALQ/USP, Piracicaba,SP. The detection of the virus was made by inoculation of leaf extracts of cucurbits in papaya cv. Golden. The papaya plants were assessed by symptoms, PTAELISA and RT-PCR. None of papaya plants exhibited symptoms of mosaic, while the ci gene, but not the cp, was detected in a sample of leaves of papaya, indicating that at least one clump of zucchini squash plant was infected. Finally, during the field test at ESALQ/USP, a papaya plant was found showing severe symptoms severe yellow leaf mosaic, leaf distortion and systemic necrosis, different from those induced by PRSV-P. Biological, serological and molecular tests confirmed the infection with AMV. This is the first report of natural infection of papaya with this virus.

Durante o amadurecimento ocorrem profundas alterações na composição química dos frutos e a expressão gênica desempenha papel fundamental no controle desse processo. Apesar da importância comercial do mamão, as informações a respeito da expressão gênica durante o amadurecimento são limitadas. Assim, nessa tese, técnicas de estabelecimento de perfis de RNA mensageiro, como Differential Display-PCR, cDNA-AFLP e Cross-Species Microarray, foram aplicadas para a identificação de genes com expressão alterada. Alguns genes ligados ao metabolismo e transporte de açúcares, de lipídeos e carotenóides, à degradação de parede celular e stress, e fatores de transcrição dependentes e independentes de hormônios vegetais pareceram apresentar diferenças de expressão durante o amadurecimento do mamão papaia. O isolamento dos genes diferencialmente expressos permitiu traçar um panorama da expressão gênica do fruto e, dessa maneira, a relação das funções dos genes com o amadurecimento do mamão contribuiu para o aumento do entendimento acerca da qualidade pós-colheita do fruto. / Ripening affects the quality of fleshy fruits by changing the chemical composition, and gene expression regulates most part of these transformations. Although papaya fruit is an important Brazilian crop, there are restricted studies concerning its ripening and gene expression. In this work, it is described the use of some RNA profiling techniques, such as Differential Display-PCR, cDNA-AFLP and Cross-Species Microarray, to identify ripening-related genes in papaya fruit. Using these techniques, some differentially expressed genes during papaya fruit ripening were isolated. Their functions were associated with metabolism and transport of sugars, lipids and carotenoids, cell wall disassembly, stress and transcription factors dependent and independent of plant hormones. In this way, it was proposed a pattern of gene expression during papaya fruit ripening, at least for those isolated genes, and the assemblage of these data with other authors data can locate fruit handling to a better level, minimizing postharvest losses and increasing papaya fruit shelf-life.

No estado do Espírito Santo (ES), uma das principais áreas produtoras de mamão do país, a eliminação sistemática de plantas doentes tem sido aplicada desde a década de 1980 para o controle do mosaico do mamoeiro (Papaya ringspot virus - type P; PRSV-P). O uso permanente dessa prática nos últimos 25 anos levou a uma aparente seleção e predominância de isolados fracos do vírus. Os objetivos deste trabalho foram: investigar a prevalência desses isolados fracos, bem como a estabilidade e o efeito protetor contra isolados severos do vírus; estudar a infecção natural de abobrinha de moita (Cucurbita pepo cv. Caserta) e abóbora moranga (C. maxima cv. Exposição) com o PRSV-P quando plantadas ao lado de mamoeiros infectados e caracterizar um isolado do Alfalfa mosaic virus (AMV) em infecção natural em mamoeiro. A detecção de possíveis isolados fracos do vírus foi realizada por PTAELISA, microscopia eletrônica e RT-PCR. Todos os isolados também foram inoculados mecanicamente em mamoeiro cv. Golden para avaliação de sintomas. Sequências de nucleotídeos e de aminoácidos deduzidos do gene da proteína capsidial de alguns isolados fracos mostraram identidades superiores a 89% e 90%, respectivamente, com isolados do PRSV-P. De 119 amostras de mamoeiros analisadas, 86 estavam infectadas com o PRSV-P, mas somente 75 induziram sintomas fracos em mamoeiros. Quatro isolados fracos foram selecionados ao acaso para estudos de estabilidade, e de proteção em casa de vegetação. Apenas dois isolados fracos induziram sintomas estáveis em mamoeiros até a oitava transferência. A proteção total só foi obtida com plantas premunizadas com dois isolados fracos e desafiados com o isolado PRSV-PES. Plantas de mamoeiros cv. Golden premunizadas com vários isolados fracos do PRSV-P foram expostas em condições de campo na ESALQ/USP, Piracicaba, SP, em dois experimentos independentes. Poucas plantas permaneceram com sintomas fracos de mosaico até o final dos experimentos. Uma terceira exposição foi realizada em Linhares, ES, com mamoeiros cvs. Sunrise Solo e Golden premunizados com oito isolados fracos, coletados nos experimentos em campo na ESALQ/USP. Apenas uma planta premunizada com um isolado fraco permaneceu com sintomas leves da doença até a última avaliação. Tentativas de detectaçao de infecções naturais de cucurbitáceas com o PRSV-P foram realizados em dois plantios de abobrinha de moita e dois de abóbora moranga, na ESALQ/USP, Piracicaba, SP. A detecção do vírus foi feita por meio da inoculação de extratos foliares das cucurbitáceas em mamoeiros cv. Golden. Os mamoerios foram avaliados por meio de sintomas, PTA-ELISA e RT-PCR. Nenhuma planta de mamoeiro inoculada com extratos foliares das duas cucurbitáceas exibiu sintomas de mosaico, embora o gene ci, mas não o cp, tenha sido detectado em uma amostra de folhas de mamoeiro, indicando que ao menos uma planta de abobrinha de moita estava infectada. Finalmente, no decorrer dos ensaios de campo na ESALQ/USP, constatou-se uma planta de mamoeiro apresentando sintomas severos de mosaico amarelo, deformação foliar e necrose sistêmica, diferente daqueles induzidos pelo PRSV-P. Análises biológicas, sorológica e moleculares confirmaram tratar-se do AMV. Este é o primeiro relato de infecção natural de mamoeiro com esse vírus. / Papaya ringspot virus type P (PRSV-P) causes the major disease in Brazilian papaya orchards that result in significant yield losses. In Espírito Santo state systematic rouging of infected plants has been applied since early 1980s for the control of this disease. Its permanent use over the last 25 years has lead to an apparent selection and predominance of mild strains throughout papaya orchards. The objectives of this work were to investigate the prevalence of mild isolates, as well the stability and protective effect against severe isolates of the virus; The aim of this work was to study the natural infecction of zucchini squash (Cucurbita pepo cv. Caserta) and pumpkin (C. maxima cv. Exposição) grown near to papaya trees infected with PRSV-P and characterize an isolate of Alfalfa mosaic virus (AMV) in natural infection in papaya. The detection of possible mild isolates of the virus was performed by PTA-ELISA, electron microscopy and RT-PCR. All isolates were inoculated mechanically in papaya cv. Golden for symptoms evaluation. Nucleotides and deduced amino acids sequences of the coat protein gene of some mild isolates showed identities above 89% and 90%, respectively, with isolates of PRSV-P. Of 119 samples from papaya plants analyzed, 86 were infected with PRSV-P and 75 induced mild symptoms on papaya. Four mild isolates were randomly selected for stability and protection studies under greenhouse. Only two isolates induced mild symptoms on papaya and remained stables until the eighth transference. Full protection was obtained with preimmunized plants with two mild isolates and challenged with the isolate PRSV-P-ES. Plants of papaya cv. Golden preimmunized with several mild isolates of PRSV-P were exposed under field conditions at ESALQ/USP, Piracicaba,SP, in two independent experiments. Few plants remained with mild mosaic symptoms at the end of the experiments. A third field exposition was held in Linhares,ES, with papaya cvs. Golden and Sunrise Solo preimmunized with eight mild isolates, collected in field experiments at ESALQ/USP. Only one plant preimmunized with a mild isolate remained with mild symptoms of the disease until the last evaluation. Attempts of detection of natural infections of cucurbits with PRSV-P were carried out in two plantations of zucchini squash and pumpkin at ESALQ/USP, Piracicaba,SP. The detection of the virus was made by inoculation of leaf extracts of cucurbits in papaya cv. Golden. The papaya plants were assessed by symptoms, PTAELISA and RT-PCR. None of papaya plants exhibited symptoms of mosaic, while the ci gene, but not the cp, was detected in a sample of leaves of papaya, indicating that at least one clump of zucchini squash plant was infected. Finally, during the field test at ESALQ/USP, a papaya plant was found showing severe symptoms severe yellow leaf mosaic, leaf distortion and systemic necrosis, different from those induced by PRSV-P. Biological, serological and molecular tests confirmed the infection with AMV. This is the first report of natural infection of papaya with this virus.

Fruit and vegetables are often spoilt during storage, handling and transportation due to microorganisms. The common spoilage causes are fungi within the order Mucorales, the largest order of the class Zygomycetes. Such spoilage can result in reduced food supplies, poor quality and severe losses to producers and traders. The study was to investigate the type of Mucorales prevalent in various commodities and in a particular market than others. Fifty infected papaya, peaches and strawberries were collected at five occasions from large, medium and small markets. Isolation was done aseptically in a biosafety cabinet. Mucorales were identified morphologically, through culture based tests and molecular techniques. Mucorales isolated are Rhizopus stolonifer, Mucor circinelloides and Mucor racemosus. Mucorales were isolated at a higher rate in samples collected from the small market than other two markets. Spoilage in all three markets is assumed to be influenced by lack of modified temperatures in the storage room. / Life and Consumer Sciences / M. Sc. (Life Sciences)

Made available in DSpace on 2014-06-11T19:32:27Z (GMT). No. of bitstreams: 0 Previous issue date: 2004-12-20Bitstream added on 2014-06-13T21:04:24Z : No. of bitstreams: 1 giannoni_ja_dr_botfca.pdf: 416586 bytes, checksum: 823a84b7d402557839873c28c91f8b12 (MD5) / Esta pesquisa teve por objetivo utilizar diferentes doses de irradiação gama sobre frutos de mamão 'Formosa' (Carica papaya L.) pré-cortados e refrigerados, visando facilitar as etapas do processamento mínimo e o consumo, além de encontrar a dose ideal de irradiação que proporcione total segurança alimentar com relação aos microrganismos, ampliando, desta forma, o período de vida útil dos frutos e mantendo as características de qualidade. Todo o processamento do mamão até a embalagem foi executado na Empresa Verde Limpo, situada em Botucatu/SP. Os frutos já embalados foram irradiados na Companhia Brasileira de Esterilização (CBE), em Jarinú/SP. As doses aplicadas foram 0,0; 0,2; 0,4; 0,6; 0,8 e 1,0kGy. Após a irradiação os frutos minimamente processados foram armazenados à temperatura de 9 l 1ºC e umidade relativa de 90 l 5% durante nove dias. As avaliações foram a cada dois dias, exceto as análises microbiológicas que foram nos 1º, 5º e 9º dias de conservação. As alterações na qualidade pós-colheita foram detectadas por meio das seguintes análises: perda de massa fresca (PMF), aparência, textura, acidez titulável (AT), pH, sólidos solúveis (SS), vitamina C, açúcares totais (A.Totais) e redutores (AR), sacarose (S), pectinas total (PT) e solúvel (PS), enzimas poligalacturonase (PG) e pectina metilesterase (PME), análise sensorial (cor, aroma, textura e sabor), índice de doenças e conservação pós-colheita. Para as análises microbiológicas foram identificadas bactérias aeróbicas (mesófilas e psicrotróficas), fungos (leveduras e bolores) e coliformes (totais e fecais). O delineamento estatístico empregado foi DIC inteiramente casualizado com quatro repetições por tratamento, utilizando o programa SISVAR® e teste de Scott-Knott ao nível de 5% de significância... / The objective of this research was to evaluate the influence of gamma irradiation on 'Formosa' papaya fresh-cut fruits (Carica papaya L.), stored under refrigeration, in order to facilitate the minimal processing stage and human consumption, finding ideal dose of irradiation that provides total nutritional safety against microorganisms, enlarging fruit shelf life and sustaining quality characteristics. Processing till packing of papaya was executed in Verde Limpo Enterprise, situated on Botucatu/SP. Packing fruits were irradiated on Companhia Brasileira de Irradiação (CBE), placed at Jarinú/SP. Used dose were 0,0; 0.2; 0.4; 0.6; 0.8; and 1.0kGy. After irradiation, the fruits were stored under temperatures of 48.2ºF l 33.8ºF and relative humidity of 90 l 5%, during 9 days and appraised each 2 days. Evaluations were performed each two days, except microbiological analysis, carried up on 1st, 5th and 9th days of conservation. Changes in postharvest quality were detected in the following analysis: loss of fresh weight (LFW), appearance, firmness, titratable acidity (TA), pH, total soluble solids (TSS), vitamin C, total reducer sugars (TRS), reducer sugar (RS), sucrose (S), total pectin (TP), soluble pectin (SP), activity of polygalacturonase (aPG) and pectin methyl esterase (aPME), sensorial analysis (color, aroma, firmness and flavor), disease index and postharvest conservation. Microbiological analysis was performed to identify aerobic bacteria (mesophilic and psychrotrophic), fungi (yeasts and moulds) and coliforms (total and fecal). Data were analyzed according to a completely randomized design, with 4 repetitions per treatment, using SISVAR™ program and Scott-Knottþs test at 5% level of significance. Based on results obtained, it was observed that appearance, color, TA, TP and aPME were significantly improved by gamma irradiation at 0.6kGy...(Complete abstract, click electronic access below)

Orientador: Rogério Lopes Vieites / Banca: Giuseppina Pace P. Lima / Banca: Maria Amalia Brunini / Banca: Moacir Pasqual / Banca: José Darlan Ramos / Resumo: Esta pesquisa teve por objetivo utilizar diferentes doses de irradiação gama sobre frutos de mamão 'Formosa' (Carica papaya L.) pré-cortados e refrigerados, visando facilitar as etapas do processamento mínimo e o consumo, além de encontrar a dose ideal de irradiação que proporcione total segurança alimentar com relação aos microrganismos, ampliando, desta forma, o período de vida útil dos frutos e mantendo as características de qualidade. Todo o processamento do mamão até a embalagem foi executado na Empresa Verde Limpo, situada em Botucatu/SP. Os frutos já embalados foram irradiados na Companhia Brasileira de Esterilização (CBE), em Jarinú/SP. As doses aplicadas foram 0,0; 0,2; 0,4; 0,6; 0,8 e 1,0kGy. Após a irradiação os frutos minimamente processados foram armazenados à temperatura de 9 l 1ºC e umidade relativa de 90 l 5% durante nove dias. As avaliações foram a cada dois dias, exceto as análises microbiológicas que foram nos 1º, 5º e 9º dias de conservação. As alterações na qualidade pós-colheita foram detectadas por meio das seguintes análises: perda de massa fresca (PMF), aparência, textura, acidez titulável (AT), pH, sólidos solúveis (SS), vitamina C, açúcares totais (A.Totais) e redutores (AR), sacarose (S), pectinas total (PT) e solúvel (PS), enzimas poligalacturonase (PG) e pectina metilesterase (PME), análise sensorial (cor, aroma, textura e sabor), índice de doenças e conservação pós-colheita. Para as análises microbiológicas foram identificadas bactérias aeróbicas (mesófilas e psicrotróficas), fungos (leveduras e bolores) e coliformes (totais e fecais). O delineamento estatístico empregado foi DIC inteiramente casualizado com quatro repetições por tratamento, utilizando o programa SISVAR® e teste de Scott-Knott ao nível de 5% de significância...(Resumo completo, clicar acesso eletrônico abaixo) / Abstract: The objective of this research was to evaluate the influence of gamma irradiation on 'Formosa' papaya fresh-cut fruits (Carica papaya L.), stored under refrigeration, in order to facilitate the minimal processing stage and human consumption, finding ideal dose of irradiation that provides total nutritional safety against microorganisms, enlarging fruit shelf life and sustaining quality characteristics. Processing till packing of papaya was executed in Verde Limpo Enterprise, situated on Botucatu/SP. Packing fruits were irradiated on Companhia Brasileira de Irradiação (CBE), placed at Jarinú/SP. Used dose were 0,0; 0.2; 0.4; 0.6; 0.8; and 1.0kGy. After irradiation, the fruits were stored under temperatures of 48.2ºF l 33.8ºF and relative humidity of 90 l 5%, during 9 days and appraised each 2 days. Evaluations were performed each two days, except microbiological analysis, carried up on 1st, 5th and 9th days of conservation. Changes in postharvest quality were detected in the following analysis: loss of fresh weight (LFW), appearance, firmness, titratable acidity (TA), pH, total soluble solids (TSS), vitamin C, total reducer sugars (TRS), reducer sugar (RS), sucrose (S), total pectin (TP), soluble pectin (SP), activity of polygalacturonase (aPG) and pectin methyl esterase (aPME), sensorial analysis (color, aroma, firmness and flavor), disease index and postharvest conservation. Microbiological analysis was performed to identify aerobic bacteria (mesophilic and psychrotrophic), fungi (yeasts and moulds) and coliforms (total and fecal). Data were analyzed according to a completely randomized design, with 4 repetitions per treatment, using SISVAR™ program and Scott-Knottþs test at 5% level of significance. Based on results obtained, it was observed that appearance, color, TA, TP and aPME were significantly improved by gamma irradiation at 0.6kGy...(Complete abstract, click electronic access below) / Doutor

Durante o amadurecimento ocorrem profundas alterações na composição química dos frutos e a expressão gênica desempenha papel fundamental no controle desse processo. Apesar da importância comercial do mamão, as informações a respeito da expressão gênica durante o amadurecimento são limitadas. Assim, nessa tese, técnicas de estabelecimento de perfis de RNA mensageiro, como Differential Display-PCR, cDNA-AFLP e Cross-Species Microarray, foram aplicadas para a identificação de genes com expressão alterada. Alguns genes ligados ao metabolismo e transporte de açúcares, de lipídeos e carotenóides, à degradação de parede celular e stress, e fatores de transcrição dependentes e independentes de hormônios vegetais pareceram apresentar diferenças de expressão durante o amadurecimento do mamão papaia. O isolamento dos genes diferencialmente expressos permitiu traçar um panorama da expressão gênica do fruto e, dessa maneira, a relação das funções dos genes com o amadurecimento do mamão contribuiu para o aumento do entendimento acerca da qualidade pós-colheita do fruto. / Ripening affects the quality of fleshy fruits by changing the chemical composition, and gene expression regulates most part of these transformations. Although papaya fruit is an important Brazilian crop, there are restricted studies concerning its ripening and gene expression. In this work, it is described the use of some RNA profiling techniques, such as Differential Display-PCR, cDNA-AFLP and Cross-Species Microarray, to identify ripening-related genes in papaya fruit. Using these techniques, some differentially expressed genes during papaya fruit ripening were isolated. Their functions were associated with metabolism and transport of sugars, lipids and carotenoids, cell wall disassembly, stress and transcription factors dependent and independent of plant hormones. In this way, it was proposed a pattern of gene expression during papaya fruit ripening, at least for those isolated genes, and the assemblage of these data with other authors data can locate fruit handling to a better level, minimizing postharvest losses and increasing papaya fruit shelf-life.

Total soluble solids (TSS) is a reliable indicator of melon eating quality, with a minimum standard of 10% recommended. The state of Australian melon production with respect to this quality criterion was considered within seasons, between growing districts and over seasons. It was concluded that improvement in agronomic practice and varietal selection is required to produce sweeter melons. The scientific literature addressing melon physiology and agronomy was summarised, as a background to the work that is required to improve melon production practices in Australia. The effect of source sink manipulation was assessed for commercially grown and glasshouse grown melon plants. The timing of fruit thinning, pollination scheduling, the application of a growth inhibitor and source biomass removal were assessed in relation to fruit growth and sugar accumulation. Results are interpreted against a model in which fruit rapidly increase in weight until about two weeks before harvest, with sugar accumulation continuing as fruit growth ceases. Thus treatment response is very dependant on timing of application. For example, fruit thinning at 25 days before harvest resulted in further fruit set and increased fruit weight but did not impact on fruit TSS (at 9.8%, control 9.3%), while thinning at 5 days before harvest resulted in a significant (Pless than 0.05) increase in fruit TSS (to 10.8%, control 9.3%) and no increase in fruit weight or number. A cost/ benefit analysis is presented, allowing an estimation of the increase in sale price required to sustain the implementation of fruit thinning. The effect of irrigation scheduling was also considered with respect to increasing melon yield and quality. To date, recommended practice has been to cause an irrigation deficit close to fruit harvest, with the intent of 'drying out' or 'stressing' the plant, to 'bring on' maturity and increase sugar accumulation. Irrigation trials showed that keeping plants stress-free close to harvest and during harvest, facilitated the production of sweeter fruit. The maintenance of a TSS grade standard using either batch based (destructive) sampling or (non-invasive) grading of individual fruit is discussed. On-line grading of individual fruit is possible using near infrared spectroscopy (NIR), but the applicability of the technique to melons has received little published attention. Tissue sampling strategy was optimised, in relation to the optical geometry used (in commercial operation in Australia), both in terms of the diameter and depth of sampled tissue. NIR calibration model performance was superior when based on the TSS of outer, rather than inner mesocarp tissue. However the linear relationship between outer and middle tissue TSS was strong (r2 = 0.8) in immature fruit, though less related in maturing fruit (r2 = 0.5). The effect of fruit storage (maturation/senescence) on calibration model performance was assessed. There was a negligible effect of fruit cold storage on calibration performance. Currently, the agronomist lacks a cost-effective tool to rapidly assess fruit TSS in the field. Design parameters for such a tool were established, and several optical front ends compared for rapid, though invasive, analysis. Further, for visualisation of the spatial distribution of tissue TSS within a melon fruit, a two-dimensional, or hyper-spectral NIR imaging system based on a low cost 8-bit charge coupled device (CCD) camera and filter arrangement, was designed and characterised.