Made available in DSpace on 2016-08-31T13:24:18Z (GMT). No. of bitstreams: 1 DanielleSO_DISSERT.pdf: 272825 bytes, checksum: 7bcf15bed78b49e71e31ce9b22399ffd (MD5) Previous issue date: 2010-06-07 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / Production of melon, which is moderately sensible to soil salinity, using water with high content of salts, inspired this work, which objectives were to quantify alterations on some soil salinity parameters during one crop cycle in two melon production areas, besides verifying the influence of such alterations on yield and quality of fruits. To accomplish this task, one cycle of commercial fertirrigated melon production was monitored in two different areas of W.G Farm, in Baraúna, RN, Brazil, where was grown the melon hybrid Iracema . Sampling was carried out in a grid scheme, with a 20 x 20 m regular spacing, which resulted in 40 plots. In each plot fruits were collected for yield determinations (number, yield and fruit mean weight of export, national and marketable fruits) and quality determinations (soluble solid content (TSS), pulp firmness and thickness). Soil characteristics determined in the beginning and in the end of crop cycle were pH, Electrical Conductivity of Soil Saturated Paste Extract (CEes), contents of Ca2+, Mg2+, K+ and Na+, Exchangeable Sodium Percentage (ESP) and the ratios Ca:Mg, Ca:K and Mg:K. Data analysis included descriptive statistics; Spearman correlation and regression analysis for identification of variability sources of yield and quality. Melon fruit yield and quality had higher influence of initial values of soil salinity parameters than of final values. Soil Mg2+ contents and CEes did not showed increase during melon cycle in both areas. Ca2+ content increased only at Bismarck area, where its final values showed positive effects on fruit pulp firmness and thickness. Ca2+ to Mg2+ ratio of Bismarck area increased 23,7 % and its final values showed positive effect on number and yield of export type and marketable fruits. Na+ contents and ESP on both areas showed increase around four times, from beginning to cycle end, but only final values of Sumidouro area showed positive effects: Na+ benefited number and yield of export type and marketable fruits, and ESP benefited yield of the same types. Increase in soil pH was around 5% on both areas, but only at Sumidouro the final values showed negative effects on mean weight of export type and marketable fruits, and on TSS. / A produção de melão, que é moderadamente sensível à salinidade, com águas contendo elevados teores de sais motivou a realização deste trabalho, visando quantificar alterações nas características de salinidade do solo durante um ciclo em duas áreas de produção, além de verificar se estas alterações influenciaram características de produção e de qualidade de frutos. Para isto, acompanhou-se um ciclo de produção comercial de melão, híbrido Iracema, fertirrigado por gotejamento, em duas áreas da W.G Agropecuária Ltda., em Baraúna-RN. A amostragem foi realizada em malha com espaçamento regular de 20 m, totalizando quarenta parcelas, nas quais foram coletados os frutos para determinações de produtividade (número, produtividade e pesos médios dos frutos dos tipos exportação, mercado nacional e comerciável) e qualidade (teor de sólidos solúveis (TSS), firmeza e espessura da polpa). As características do solo determinadas, no início e no fim do ciclo, foram pH, Condutividade Elétrica do extrato de saturação (CEes), teores de Ca2+, Mg2+, K+ e Na+, Percentagem de Sódio Trocável (PST) e as relações Ca:Mg, Ca:K e Mg:K. Para analisar os dados utilizou-se a estatística descritiva para levantamento exploratório; correlação de Spearman e análise de regressão para identificar causas da variabilidade em produtividade e qualidade. Os valores de características de salinidade do solo no início do ciclo influenciaram mais a produtividade e qualidade dos frutos de melão do que no final do ciclo. O teor de Mg2+ e a CEes do solo não aumentaram do início para o fim do ciclo do meloeiro, nas duas áreas estudadas. O teor de Ca2+ no solo aumentou apenas na área Bismarck, onde seu teor no final do ciclo apresentou efeito positivo sobre a firmeza e espessura da polpa dos frutos. Número e produtividade de frutos dos tipos exportação e comerciáveis da área Bismarck tiveram efeito positivo do valor final da relação cálcio:magnésio do solo, que aumentou 23,7 % em relação ao inicial. O teor de Na+ e a PST do solo das duas áreas aumentaram ao redor de quatro vezes, do início para o final do ciclo. Apenas os valores no fim do ciclo na área Sumidouro apresentaram efeitos positivos: o Na+ favoreceu número e produtividade de frutos dos tipos exportação e comerciáveis e a PST favoreceu as produtividades dos mesmos tipos. O peso médio de frutos do tipo exportação e comerciáveis e o teor de sólidos solúveis na área Sumidouro tiveram efeito negativo do valor final de pH do solo, que aumentou ao redor de 5% nas duas áreas.

Made available in DSpace on 2015-03-26T13:39:34Z (GMT). No. of bitstreams: 1 texto completo.pdf: 1636884 bytes, checksum: c966934c707a7e6bf40bfe5aee85e5a1 (MD5) Previous issue date: 2009-09-25 / Fundação de Amparo a Pesquisa do Estado de Minas Gerais / The objective of this work was to promote the degreening, without losing internal fruit quality, of Poncã tangerine from two regions of Minas Gerais. Two experiments were carried out. In the first, the fruits were harvested from a commercial orchard in the northern region, and the second experiment used fruits from Zona da Mata. Fruits were harvested when showing minimum attributes of 35% juice, 9 ° Brix and soluble solids/tritable acidity ratio of 9.5. Then the fruits were packed in airtight boxes, which were exposed for 24, 48 and 96 h to different concentrations of ethylene gas: 0, 5, 10, 20 and 40 μL.L-1, at 20 + 1 °C and 90 + 5% relative humidity, respectively. Every 24 h, the boxes were opened for renewal of internal atmosphere, by reapplying the gas until treatment end. A post-treatment phase of 96 h duration took place at the end of each exposure time, when the fruits were kept in ethylene-free atmosphere, in cold chamber, at the same temperature and relative humidity used during the exposure to ethylene. During this phase, the fruits were evaluated every 24 h, and the difference in skin color, Hue angle of the peel, total chlorophyll and carotenoid content, soluble solids content, tritable acidity and SS/TA ratio of juice, solute leakage, CO2 production and loss of fruit fresh mass. In the first experiment, the fruits showed stronger degreening with increasing time of exposure to ethylene, most markedly for 96 h. After this exposure time, the Hue angle increased from 96.1o, in the first assessment days, to 82.3o, at the end of 96 h, which was lower than values observed in naturally degreened fruits. Fruits exposed for 24 h showed evolution of the yellow peel color similar to the untreated ones. It was observed that fruits left to ripe on the plant showed non-homogeneous peel degreening. The fruits exposed to ethylene for 96 h showed no visual signs of loss of commercial quality, although there was increased solute leakage from the peel during the treatment. Soluble solids content, tritable acidity and SS/TA ratio remained unchanged throughout the assessment period. The synthesis of total carotenoids in the peel was low, from 6.0 μg/cm2, in control fruits at the end of evaluations, to a maximum of 8.2 μg/cm2, in fruits exposed to ethylene for 96 h. This synthesis was insufficient to reach the orange color, therefore, the degreening of fruit peel was due, almost exclusively, to chlorophyll degradation. In the second experiment, the fruits showed yellowing of the peel stronger than fruits of the first experiment. The exposure time of 96 h proved to be the most efficient in promoting the fruit degreening in comparison with other times. Color evolution was quite similar between the control and fruits treated for 24 and 48 h. Fruits of all treatments had very low synthesis of total carotenoids in the peel, changing from 7.3 μg/cm2 in control fruits to 9.2 μg/cm2, maximum value observed in fruits exposed to ethylene for 96 h. Even in fruits showing the strongest yellowing, there was little participation of new synthesized carotenoids in the composition of the final color. Fruits fully developed in the plant reached the maximum degreening, becoming orange, the typical color of the species. Thus, for fruits produced in the Zona da Mata region, the post-harvest degreening with ethylene is only justified to anticipate the harvest, since the region has favorable climate to natural degreening. However, for fruits produced in northern Minas Gerais, where the high temperatures prevailing throughout the year impair the natural degreening, the postharvest use of ethylene may serve to obtain a more uniform peel color. / The objective of this work was to promote the degreening, without losing internal fruit quality, of Poncã tangerine from two regions of Minas Gerais. Two experiments were carried out. In the first, the fruits were harvested from a commercial orchard in the northern region, and the second experiment used fruits from Zona da Mata. Fruits were harvested when showing minimum attributes of 35% juice, 9° Brix and soluble solids/tritable acidity ratio of 9.5. Then the fruits were packed in airtight boxes, which were exposed for 24, 48 and 96 h to different concentrations of ethylene gas: 0, 5, 10, 20 and 40 μL.L-1, at 20 + 1 °C and 90 + 5% relative humidity, respectively. Every 24 h, the boxes were opened for renewal of internal atmosphere, by reapplying the gas until treatment end. A post-treatment phase of 96 h duration took place at the end of each exposure time, when the fruits were kept in ethylene-free atmosphere, in cold chamber, at the same temperature and relative humidity used during the exposure to ethylene. During this phase, the fruits were evaluated every 24 h, and the difference in skin color, Hue angle of the peel, total chlorophyll and carotenoid content, soluble solids content, tritable acidity and SS/TA ratio of juice, solute leakage, CO2 production and loss of fruit fresh mass. In the first experiment, the fruits showed stronger degreening with increasing time of exposure to ethylene, most markedly for 96 h. After this exposure time, the Hue angle increased from 96.1o, in the first assessment days, to 82.3o, at the end of 96 h, which was lower than values observed in naturally degreened fruits. Fruits exposed for 24 h showed evolution of the yellow peel color similar to the untreated ones. It was observed that fruits left to ripe on the plant showed non-homogeneous peel degreening. The fruits exposed to ethylene for 96 h showed no visual signs of loss of commercial quality, although there was increased solute leakage from the peel during the treatment. Soluble solids content, tritable acidity and SS/TA ratio remained unchanged throughout the assessment period. The synthesis of total carotenoids in the peel was low, from 6.0 μg/cm2, in control fruits at the end of evaluations, to a maximum of 8.2 μg/cm2, in fruits exposed to ethylene for 96 h. This synthesis was insufficient to reach the orange color, therefore, the degreening of fruit peel was due, almost exclusively, to chlorophyll degradation. In the second experiment, the fruits showed yellowing of the peel stronger than fruits of the first experiment. The exposure time of 96 h proved to be the most efficient in promoting the fruit degreening in comparison with other times. Color evolution was quite similar between the control and fruits treated for 24 and 48 h. Fruits of all treatments had very low synthesis of total carotenoids in the peel, changing from 7.3 μg/cm2 in control fruits to 9.2 μg/cm2, maximum value observed in fruits exposed to ethylene for 96 h. Even in fruits showing the strongest yellowing, there was little participation of new synthesized carotenoids in the composition of the final color. Fruits fully developed in the plant reached the maximum degreening, becoming orange, the typical color of the species. Thus, for fruits produced in the Zona da Mata region, the post-harvest degreening with ethylene is only justified to anticipate the harvest, since the region has favorable climate to natural degreening. However, for fruits produced in northern Minas Gerais, where the high temperatures prevailing throughout the year impair the natural degreening, the postharvest use of ethylene may serve to obtain a more uniform peel color.

Made available in DSpace on 2016-12-08T16:44:36Z (GMT). No. of bitstreams: 1 PGPV10MA055.pdf: 724635 bytes, checksum: 47f16229cf97fc318aa61ab151a5dad6 (MD5) Previous issue date: 2010-02-05 / The cultivar Catarina produces fruits of good quality, large size and good shape, and is resistant to the main diseases of the apple trees, scab (Venturia inaequalis) and Gala leaf spot (Glomerella cingulata). The commercial use of Catarina apples is limited by its susceptibility to bitter pit, a physiological disorder caused by Ca deficiency in the fruit. This works was carried out to evaluate: 1) the seasonal fluctuation of nutrients in the leaves and fruits of cultivars Catarina, Gala and Fuji, during the vegetative cycle; and 2) the efficiency of sources of Ca, sprayed at preharvest for bitter pit control and the preservation of fruit qualitative attributes of Catarina apples. The researchs were conduced in São Joaquim region, during two growing seasons for evaluation of the nutritional assessment (2004/2005 and 2005/2006), and during three growing seasons for the evaluation of the sources of Ca spraying (from 2004/2005 to 2006/2007). The three cultivars exhibited reductions in the concentration of N, P and K, and increases in the concentration of Ca and Mg in the leaves along the growing season. Among the cultivars, the Catarina had the smallest foliar concentrations of P, Ca and Mg. Catarina apples had the highest increment of fruit mass. Fruits of Catarina , Gala and Fuji showed reduction in the concentration of N, K, Ca and Mg along the growing season. Catarina apples had the highest concentration of K and the smallest concentration of Ca in the fruit. In the cultivars, the Ca content in the fruits increased until the harvest. Catarina had the highest Ca content in the fruit in 2004/2005, and the lowest Ca content in 2005/2006. The low Ca content in the fruit of Catarina incresead the N/Ca, K/Ca, Mg/Ca and (K+Mg)/Ca ratios, especially in 2005/2006, therefore increasing the risk of physiological disorder in the fruit. In the experiment to evaluate the efficiency of sources of Ca sprayed at preharvest, the was no effect of treatments on N, P and K concentrations in the leaves. Only in 2006/2007, preharvest spraying with CalSOL 15 (15 sprayings) increased the Ca concentration in the leaves. In 2004/2005, preharvest spraying with Calboron + CaCl2, Sett, CaCl2, Calboron and S-CaB incresead Ca concentration in the fruit. The control treatment exihibited incidences of bitter pit of 23,9% and 45,5% in 2005/2006 and 2006/2007, respectively. The treatments with Calboron, Sett, Ca Cl2 and Wuxal Cálcio in 2005/2006, and with CaCl2 and CalSOL 15 (10 and 15 sprayings) in 2006/2007, reduced the incidence of bitter pit assessed at harvest. In 2006/2007, the initial severity (at harvest) was not affected by treatments, but the treatments with CaCl2 reduced the severity of this disorder during cold storage. In 2004/2005, 2005/2006 and 2006/2007, the sources of Ca not affect the fruit weight, yield, and flesh firmness, starch index, soluble solids content (SSC), titratable acidity (TA), and SSC/TA ratio of the fruit at harvest / A cultivar Catarina produz frutos de boa qualidade, tamanho grande, bom formato e apresenta resistência às principais doenças da macieira, sarna (Venturia inaequalis) e mancha foliar de Gala (Glomerella cingulata). O plantio comercial da macieira Catarina está limitado pela suscetibilidade ao bitter pit , distúrbio fisiológico relacionado principalmente à deficiência de Ca nos frutos. Os trabalhos tiveram por objetivos avaliar: 1) a variação dos nutrientes nas folhas e nos frutos das cultivares Catarina, Gala e Fuji, durante o ciclo vegetativo, visando diagnosticar as diferenças nutricionais e relacionar com a ocorrência de bitter pit ; e 2) a eficiência de fontes de Ca em pulverização pré-colheita no controle de bitter pit e na preservação dos atributos qualitativos dos frutos da cultivar Catarina. Os trabalhos foram conduzidos na região de São Joaquim, SC, durante as safras 2004/2005 e 2005/2006 para o monitoramento nutricional, e durante as safras 2004/2005 a 2006/2007 para a avaliação das fontes de Ca. As três cultivares apresentaram reduções nos teores de N, P e K, e aumento nos teores de Ca e Mg nas folhas ao longo do ciclo vegetativo. A cultivar Catarina apresentou os menores teores de P, Ca e Mg nas folhas. Entre as cultivares, a cultivar Catarina apresentou a maior massa final dos frutos. As cultivares apresentaram reduções nos teores de N, K, Ca e Mg nos frutos ao longo do ciclo vegetativo. Os frutos da cultivar Catarina apresentou o maior teor de K e o menor teor de Ca em relação às cultivares Gala e Fuji. O conteúdo de Ca nos frutos aumentou até a colheita nas três cultivares. Na safra 2004/2005, a cultivar Catarina apresentou o maior conteúdo de Ca nos frutos, mas na safra 2005/2006, apresentou o menor conteúdo de Ca. O baixo teor de Ca nos frutos da cultivar Catarina aumentou o valor das relações N/Ca, K/Ca, Mg/Ca e (K+Mg)/Ca, principalmente na safra 2005/2006, aumentando a probabilidade da ocorrência de distúrbios fisiológicos nos frutos. No experimento de pulverização pré-colheita com fontes de Ca, não foi verificado efeito nos teores de N, P e K nas folhas. Das três safras, apenas na safra 2006/2007, o teor de Ca nas folhas aumentou com o tratamento CalSOL 15 (15 aplicações). Na safra 2004/2005, o teor de Ca nos frutos aumentou com os tratamentos Calboron + CaCl2, Sett, CaCl2, Calboron e S-CaB. Na testemunha, o bitter pit ocorreu em 23,9% e 45,5% dos frutos, nas safras 2005/2006 e 2006/2007, respectivamente. Os tratamentos Calboron, Sett, CaCl2 e Wuxal Cálcio (safra 2005/2006) e os tratamentos CaCl2 e CalSOL 15 (10 e 15 aplicações) (safra 2006/2007) reduziram a incidência de bitter pit avaliado na colheita. Na safra 2006/2007, a severidade inicial (logo após a colheita) de bitter pit não foi afetada pelos tratamentos, mas o tratamento CaCl2 reduziu a severidade final dos frutos armazenados. Nas safras 2004/2005, 2005/2006 e 2006/2007, as fontes de Ca não afetaram o peso médio, o rendimento de frutos, a firmeza da polpa, o índice de iodo-amido, o teor de sólidos solúveis (SS), a acidez titulável (AT) e relação SS/AT na colheita

FundaÃÃo Cearense de Apoio ao Desenvolvimento Cientifico e TecnolÃgico / O presente trabalho teve como objetivo estudar o efeito do armazenamento dos frutos de seis clones de aceroleira (BRS 152, BRS 235, BRS 236, BRS 237, BRS 238 e II47/1) à temperatura abaixo da temperatura mÃnima de seguranÃa (TMS), analisando os efeitos na qualidade dos frutos, no conteÃdo de compostos bioativos e na atividade enzimÃtica. Os frutos foram colhidos no inÃcio do estÃdio de maturaÃÃo, no campo experimental da Embrapa AgroindÃstria Tropical, na cidade de Pacajus, sendo acondicionados em bandejas de plÃstico envolvidas com filme de PVC, as quais foram armazenadas em cÃmara fria Ãs temperaturas de 4 e 8 ÂC por atà 12 dias. A cada trÃs dias foram retiradas amostras (bandejas contendo cerca de 180 g de frutos) para realizaÃÃo das anÃlises, sendo os frutos, em seguida, submetidos a um processamento em multiprocessador com peneira de 1 mm para obtenÃÃo da polpa. O delineamento experimental foi o inteiramente casualizado, em esquema fatorial 6 x 5, com trÃs repetiÃÃes, sendo o primeiro fator os seis clones de aceroleira e o segundo os tempos de armazenamento dos frutos (0, 3, 6, 9 e 12 dias). Os dados foram submetidos à anÃlise de variÃncia e, quando a interaÃÃo entre os dois fatores foi significativa, eles foram submetidos à anÃlise de regressÃo; quando nÃo houve interaÃÃo significativa foi realizado o teste de Tukey a 5%. Para avaliar a qualidade dos frutos, foram analisadas as caracterÃsticas fÃsicas (firmeza, perda de massa e cor) e fÃsico-quÃmicas e quÃmicas (pH, sÃlidos solÃveis, acidez titulÃvel e aÃÃcares solÃveis totais). Como resultado, foi observado que tais caracterÃsticas dos frutos acondicionados a 4 e 8 ÂC foram praticamente as mesmas, exceto com relaÃÃo à perda de massa que foi 31% menor a 4 ÂC. Portanto, de modo geral, o armazenamento dos frutos a 4 ÂC nÃo comprometeu os parÃmetros de qualidade dos frutos, quando comparados com aqueles armazenados na TMS para a acerola (8 ÂC). Com relaÃÃo ao conteÃdo dos compostos bioativos (Ãcido ascÃrbico, carotenoides e antocianinas) dos frutos armazenados a 4 ÂC, de modo geral, ele nÃo diferiu muito daquele dos frutos armazenados na temperatura de 8 ÂC. Houve uma tendÃncia de queda nos teores de Ãcido ascÃrbico durante o armazenamento nas duas temperaturas, resultado tambÃm observado para os teores de antocianinas a 8 ÂC. Por outro lado, os de carotenoides apresentaram tendÃncia de aumento à 4 ÂC, mas nÃo variaram com o tempo de armazenamento a 8 ÂC. O clone II47/1 foi o que apresentou frutos com maiores teores de Ãcido ascÃrbico, carotenoides e antocianinas nas duas temperaturas de armazenamento. De modo geral, as enzimas oxidativas de fenÃis (polifenoloxidase e peroxidase do guaiacol) dos frutos dos clones armazenados a 4 e 8 ÂC apresentaram comportamentos semelhantes durante o acondicionamento refrigerado. O estudo com as enzimas antioxidativas (dismutase do superÃxido, catalase e peroxidase do ascorbato) revelou que os frutos armazenados a 4 ÂC apresentaram, respectivamente, valores de atividade da dismutase do superÃxido e da catalase 263% e 37%, em mÃdia, maiores que aqueles armazenados na TMS para a acerola (8 ÂC). Tais resultados sugerem que a 4 ÂC os frutos estÃo sob estresse oxidativo. A catalase foi a principal enzima removedora de perÃxido de hidrogÃnio nos frutos, tendo sua atividade intensificada apÃs o 6 dia de armazenamento. Os resultados sugerem que os clones II47/1 e o BRS 152 sÃo resistentes as condiÃÃes de armazenamento nas temperaturas 4 e 8 ÂC. / The present work aimed to study the effect of fruit storage of six clones of acerola (BRS 152 BRS 235 BRS 236 BRS 237 BRS 238 and II47/1) at temperature below the temperature minimum security (TMS), analyzing the effects on fruit quality, the content of bioactive compounds and enzyme activity. The fruits were harvested at the beginning of ripening stage on the experimental field of Embrapa Tropical, in the city of Pacajus being packed in plastic trays involved with PVC film, which were stored in cold storage at temperatures of 4 ÂC and 8 ÂC for up to 12 days. Every three days samples were withdrawn (tray containing about 180 g of fruit) for carrying out analyzes, and the fruits are then subjected to a processing multiprocessor 1 mm screen to obtain the pulp. The experimental design was completely randomized in factorial scheme 6 x 5 with three replications, with the first factor corresponding to six clones of acerola and the second one corresponding to the five times of fruit storage (0, 3, 6, 9 and 12 days). The data were subjected to analysis of variance and, when the interaction between the two factors was significant, they were subjected to regression analysis; when there was no significant interaction, the means were compared by Tukeyâs test at 5% of probability. To assess the quality of fruits, it was analyzed their physical (strength, weight loss and color) and physico-chemical and chemical characteristics (pH, soluble solids, titratable acidity and total soluble sugars). As a result, it was observed that the characteristics of the fruit stored at 4 ÂC to 8 ÂC were practically the same, except with respect to mass loss, which was 31% lower at 4 ÂC. Therefore, in general, the fruit storage at 4 ÂC did not affect the quality parameters of fruits, compared to those stored in the TMS to the acerola (8 ÂC). Regarding the content of bioactive compounds (ascorbic acid, carotenoids and anthocyanins), the fruit stored at 4 ÂC, generally did not differ from that of the fruit stored at 8 ÂC. There was a trend towards a decrease in the ascorbic acid content during storage at both temperatures, a result also observed for the anthocyanins to 8 ÂC. On the other hand, the carotenoid content increased at 4 ÂC and did not change with time of storage at 8 ÂC. The fruits of clone II47/1 had the higher contents of ascorbic acid, carotenoids and anthocyanins in the two storage temperatures. In general the phenol oxidizing enzymes (polyphenol oxidase and guaiacol peroxidase) of fruit clones stored at 4 and 8 ÂC had similar behavior during cold storage, and the fruits of clones II47/1 and BRS 152 had the higher enzyme activity during storage at both temperatures The study about the antioxidant enzymes (superoxide dismutase catalase and ascorbate peroxidase) revealed that fruits stored at 4 ÂC showed respectively activity values of superoxide dismutase and catalase 263% and 37% on average higher than those stored at TMS for acerola (8 ÂC) These results suggest that the fruits storaged at 4 ÂC are under oxidative stress Catalase was the main hydrogen peroxide removing enzyme in fruit which activity increased after 6 days of storage The results suggest that clones II47 / 1 and BRS 152 are resistant storage conditions at temperatures 4 and 8 ÂC

A laranjeira \'Pera\' é a cultivar mais plantada na citricultura brasileira. Com a incidências de doenças e aumento do custos de produção na citricultura, torna-se necessário a avaliação de materiais genéticos mais promissores que a laranjeira \'Pera\'. Portanto, buscou-se avaliar o desempenho horticultural de laranjeiras doces consideradas meia-estação e identificar aquelas superiores à cultivar padrão (Pera IAC). Foram avaliadas dezessete cultivares de laranja doce (Pera IAC, Pera IAC 2000, Pera 2, Pera 3, Pera 4, Pera Alexandre Maróstica, Pera Milton Teixeira, Seleta Amarela, Seleta Rio, Homosassa, Finike, Biondo, Bidwells Bar, Sanguínea, Vaccaro Blood, Torregrosa e Jaffa) enxertadas em tangerineira \'Sunki\'. O experimento foi instalado em maio de 2007, no espaçamento 6,5 x 2,5 m e conduzido sem irrigação. Avaliaram-se o crescimento vegetativo, produção, eficiência produtiva, abscisão dos frutos, sensibilidade ao déficit hídrico, incidência de podridão floral (PFC), incidência e severidade de mancha preta dos citros (MPC), qualidade e curva de maturação dos frutos. As médias das variáveis foram comparadas com a cultivar padrão (Pera IAC) e analisadas pelo teste de Dunnett (P < 0,05). Para sensibilidade ao déficit hídrico e curvas de maturação foram realizadas analises de regressão. As plantas de laranja \'Pera 3\' registraram as menores alturas, no sétimo ano após o plantio. As plantas de laranja \'Pera Milton Teixeira\' e \'Pera Alexandre Maróstica\' foram os únicos materiais que registraram produções acumuladas superiores às das plantas de laranja \'Pera IAC\'. As plantas de \'Seleta Amarela\', \'Pera 3\', \'Pera 4\', \'Vaccaro Blood\' e \'Pera Milton Teixeira\' registraram as maiores eficiências produtivas. As plantas da laranja \'Pera IAC\' registraram as maiores alternâncias produtivas e as plantas de laranja \'Sanguínea\' registraram as menores alternâncias. As seleções \'Pera 2\', \'Pera 3\', \'Pera 4\' e \'Pera Milton Teixeira\' registraram as menores abscisões de frutos. As plantas das laranjas \'Pera Milton Teixeira\', \'Pera IAC\', \'Pera IAC 2000\', \'Pera 2\', \'Seleta Rio\' e \'Pera 3\' foram classificadas como cultivares de alta sensibilidade ao déficit hídrico e as plantas das laranjas \'Bidwells Bar\', \'Jaffa\', \'Torregrosa\' e \'Sanguínea\' como de baixa sensibilidade. As menores incidências de MPC foram registradas nos frutos da laranjeira \'Pera IAC\' e não houve diferenças entre as cultivares para incidência de PFC. Para o teor de sólidos solúveis, apenas os frutos da laranja \'Finike\', \'Pera 2\' e \'Pera Alexandre Maróstica\' foram superiores aos da cultivar padrão. A seleções \'Pera IAC\', \'Pera 2\', \'Pera 3\' e \'Pera 4\' apresentaram alta similaridade fenotípica entre si. Ao estabelecer a curva de maturação, verificou-se uma maior precocidade da laranjeira \'Seleta Rio\' e uma maturação mais tardia para a seleção \'Pera Alexandre Maróstica\' quando comparadas a laranjeira \'Pera IAC\'. / \'Pera\' is the most widely planted sweet orange cultivar in the Brazilian citrus industry. Due to incidences of diseases and increase in production costs it is necessary to find promising genetic materials than \'Pera\' sweet orange. Therefore, the horticultural performance of sweet oranges, considered mid-season, were evaluated and identified those ones which were better than standard cultivar (Pera IAC). Seventeen sweet orange cultivars (Pera IAC, Pera IAC 2000, Pera 2, Pera 3, Pera 4, Pera Alexandre Maróstica, Pera Milton Teixeira, Seleta Amarela, Seleta Rio, Homosassa, \'Finike, Biondo, Bidwells Bar, Sanguínea, Vaccaro Blood, Torregrosa e Jaffa) were evaluated, all of then were grafted on \'Sunki\' mandarin and were nonirrigated. The experimental orchard was planted in May 2007, from 12 month-old plants (nursery trees) disposed in a 6,5 m × 2,5 m spacing. We evaluated the vegetative growth, yield, yield efficiency, fruit drop, sensitivity to drought, incidence of postbloom fruit drop (PFD), incidence and severity Black Spot of Citrus (CBS), fruit quality and index of ripeness. The averages of variables were compared with the standard cultivar (Pera IAC) and analyzed by Dunnett\'s Test (P < 0.05). For sensitivity to drought and index of ripeness were performed regression analyzes. The lowest hight and canopy volume were recorded in the \'Pera 3\' sweet orange trees seven years after planting. The \'Pera Milton Teixeira\' and \'Pera Alexandre Marostica\' sweet orange trees were the only materials which had superiority over the \'Pera IAC\' sweet orange trees regarding cumulative yield. The largest yield efficiency was registered in \'Seleta Amarela\', \'Pera 3\', \'Pera 4\', \'Vaccaro Blood\' and \'Pera Milton Teixeira\' sweet orange trees. The most alternate bearing index was found in the standard cultivar and \'Sanguinea\' sweet orange trees showed smaller bearing index. Smaller fruit drop were checked in cultivars Pera 2, Pera 3, Pera 4 and Pera Milton Teixeira. The \'Pera Milton Teixeira\', \'Pera IAC\', \'Pera IAC 2000\', \'Pera 2\', \'Seleta Rio\' and \'Pera 3\' sweet orange trees showed high sensitivity to drought while the \'Bidewells Bar\', \'Jaffa\', \'Torregrosa\' and \'Sanguínea\' sweet orange trees showed low sensitivity. Regarding the evaluated diseases, the orange \'Pera IAC\' recorded the lowest incidences of MPC and PFC differences were not cheked among the cultivars. For the soluble solids content, only the \'Finike\', \'Pera 2\' and \'Pera Alexandre Marostica\' sweet oranges fruits were superior to standard. The cultivars Pera IAC, Pera 2, Pera 3 and Pera 4 sweet oranges showed high phenotypic similarity. The \'Seleta Rio\' sweet orange was considered early-maturing cultivar and \'Pera Alexandre Maróstica\' a late-maturing cultivar when compared \'Pera IAC\' sweet orange.

O Estado de São Paulo se destaca como uma das principais regiões produtoras de citros do mundo. Recentes estudos mostram que a área irrigada de citrus no Estado tem aumentado signicativamente nos últimos 5 anos. Porém, as limitações dos recursos hídricos e falta de informações sobre o manejo eficiênte da irrigação na cultura do citrus são os principais problemas face aos produtores. Visando atender essa necessidade, este projeto teve como objetivos determinar a evapotranspiração de uma planta jovem de limeira ácida ‘Tahiti’ (Citrus latifolia Tan.) e os coeficientes de cultivo durante a formação de um pomar. Considerando a independente contribuicão da evaporação do solo e transpiração da cultura pela substituição do coeficente de cultivo (Kc=ETc/ETo) em dois separados coeficientes; Ke, um coeficiente de evaporação de água do solo e Kcb, um coeficiente de transpiração da cultura. Avaliar o desenvolvimento vegetativo, assim como aspectos produtivos da cultura, frente a diferentes níveis de irrigação, com o fornecimento crescente de 25 a 100% da necessidade hídrica da cultura. O experimento foi realizado na ESALQ/ USP em Piracicaba - SP, em uma área irrigada por gotejamento, com plantas espaçadas de 7x4 metros entre linhas e plantas respectivamente, sendo que cada planta foi atendida por 4 pontos de molhamento no solo distribuídos de forma eqüidistantes entre si. Foi avaliado o desenvolvimento vegetativo das plantas, com base em medidas de diâmetro do caule, altura e sistema radicular. Foi realizado o monitoramento climático utilizando estação meteorológica automatizada e a obtenção da evapotranspiração da cultura por lisímetro de pesagem. Durante o período de estudo, Kc variou entre 0,6 a 1,22, e Kcb variou entre 0,4 a 1,0. Os resultados mostraram que a independente influência da evaporação do solo e transpiração é importante para melhor compreensão sobre o consumo de água de plantas jovens de lima ácida ‘Tahiti’, quando comparado a plantas adultas. Os maiores consumos foram observados no verão. A reposição de 100% da água evapotranspirada resultou em melhor desenvolvimento vegetativo de plantas jovens de limeira acida ‘Tahiti’ em condições de campo. Os resultados mostraram também que não houve diferenças entre as lâminas quanto à distribuição das raízes, de plantas jovens (33 meses) em profundidade, concentrando-se na camada de 0,0- 0,3m. Entretanto, a distribuição horizontal foi maior nos níveis baixos (0%; 25% e 50%) do que nos maiores níveis (75% e 100%). Nas plantas irrigadas com 75% e 100% houve concentração das raízes até 0,6 m, indicando que o déficit hídrico induziu o crescimento na direção horizontal. E que a profundidade e distância horizontal efetiva das raízes, de plantas com 48 meses, localizam-se a 0,6 m de profundidade. Os resultados mostraram que a irrigação induziu à precocidade da produção e ao aumento da produtividade e do número de frutos nas plantas jovens de lima ácida ‘Tahiti’ já a partir da lâmina de 25% da evapotranspiração da cultura. Quanto à qualidade de frutos, não houve diferença significativa entre os níveis de irrigação avaliados. / The State of São Paulo is one of the most important producers of citrus of the world. Recent studies showed that during the last 5 years, there was a significant increase in the area with citrus irrigation. However, the shortage of water and the unavailability of required information for efficient irrigation scheduling are the main problems that producers face. Therefore, the objective of this work was an estimate water requirement of young ‘Tahiti’ lime orchards considering the independent contributions from soil evaporation and crop transpiration by splitting the crop coefficient (Kc=ETc/ETo) into two separate coefficients; Ke, a soil evaporation coefficient and Kcb, a crop transpiration coefficient. Evaluate the effect of different irrigation levels (0 to 100% of crop evapotranspiration by weighing lysimeter) on ‘Tahiti’ acid lime young tree canopy and root growth, productivity and quality of fruit, under drip irrigation in the field. The experiment was conducted during a 3-yr period (August 2002 – May 2005) in a 1.0 ha plot planted with ‘Tahiti’ acid lime trees, grafted on ‘Swingle’ citrumelo rootstock. The trees were 1-yr old at planting, spaced 7 x 4 m. The orchard was located in Piracicaba, São Paulo State, Brazil. Each treatment was assigned to different irrigation level, based on ETc as determined by a weighing lysimeter. The trunk diameter and height tree were evaluated monthly. The roots were evaluated when the trees were 30 and 48 months old. Adopted during the first root sampling were 4 horizontal distances from the tree trunk (0.3, 0.6, 0.9 and 1.2 m) and 2 depths (0.0-0.3 and 0.3- 0.6 m). Adopted during the second sampling were 5 horizontal distances from trunk (0.3, 0.6, 0.9, 1.2 and 1.5 m), and 3 depths (0.0-0.3, 0.3-0.6 and 0.6-0.9 m). The yield was evaluated by measuring weight and number of fruits per tree in 2004 and 2005. The quality of the yield was evaluated by measuring fruit diameter, rind thickness, % of juice, total soluble solids, pH and total acidity. During the study period, Kc varied between 0.6 to 1.22, and Kcb varied between 0.4 to 1.0. The independent influence of soil evaporation and transpiration is important to better understand the water consumption of young lime tree during the growth, compared to mature lime tree. The biggest ETc and Kc were observed on summer. The results showed that young trees irrigated with 100% ETc resulted in greater growth. The results also showed that did not happen differences in root distribution in the depths, most of them at 0-0.3m. However, the horizontal distribution at lower levels (25 and 50%) of that in the biggest levels (75 and 100%) that concentrated at 0.6 m, indicating that water stress induced the root growth horizontally. The results, at the second analysis, showed that did not happen differences in root distribution soil profile, and effective depth and horizontal distance of root located to 0.6 m of depth and 0.6 of horizontally distant of tree. Finally, the irrigation induced precocity of production, increase of productivity and the fruits number already with irrigation of 25% of ETc. The quality of fruit, did not present difference among the treatments.

Submitted by Gabriela Lopes (gmachadolopesufpel@gmail.com) on 2016-10-06T18:12:15Z No. of bitstreams: 2 license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) Dissertação Ellen Cristina Perin.pdf: 2710133 bytes, checksum: 106c3030cdbbdfb20e6ff087140c2245 (MD5) / Approved for entry into archive by Aline Batista (alinehb.ufpel@gmail.com) on 2016-10-11T20:47:01Z (GMT) No. of bitstreams: 2 Dissertação Ellen Cristina Perin.pdf: 2710133 bytes, checksum: 106c3030cdbbdfb20e6ff087140c2245 (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) / Made available in DSpace on 2016-10-11T20:47:01Z (GMT). No. of bitstreams: 2 Dissertação Ellen Cristina Perin.pdf: 2710133 bytes, checksum: 106c3030cdbbdfb20e6ff087140c2245 (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) Previous issue date: 2014-02-24 / Sem bolsa / A biofortificação de culturas agrícolas é uma estratégia que vem sendo estudada e explorada com o objetivo de complementa r da alimentação pelo incremento ou melhoria na qualidade dos alimentos, visando reduzir a desnutrição e oferecer alimentos mais saudáveis. Dentre as técnicas utilizadas para realizar a biofortificação, o uso de fertilização e, mais recentemente, a aplicação de estresses abióticos controlados vem sendo abordadas, mostrando que as aplicações dessas técnicas podem acarretar no acúmulo de compostos com potencial antioxidante de interesse para promoção da saúde humana , sem prejudicar significativamente o desenvolvimento e produção das culturas. Os frutos de morango, cujas características sensoriais específicas vem promovendo aumento do seu consumo, apresentam naturalmente em sua composição compostos com potencial antioxidante, como vitamina C, compostos fenólicos e antocianinas os quais podem ter seus teores modificados de forma a melhorar seu potencial antioxidante, além de suas funções em condições de estresse como defesa. Por outro lado, o cultivo do morangueiro apresenta uma alta taxa de sensibilidade a déficits hídricos e nutricionais; a adubação empregada nessa cultura normalmente utiliza fontes solúveis de nutrientes minerais, que podem acarretar em prejuízos ao solo, desequilíbrio nutricional, lixiviação e contaminação de lençóis freáticos. Neste estudo, plantas de morangos foram submetidas a diferentes níveis de estresse hídrico e a uma adubação cuja matriz foi composta de torta de tungue e pós -derocha, efetuando-se avaliações de variáveis bioquímico-fisiológicas e moleculares. Os resultados mostraram que a adubação alternativa apresentou potencial para utilização como insumo agrícola, uma vez que aumentou a produção de frutos (23,79 % a mais que a adubação solúvel) tendo ainda proporcionado um maior acúmulo de compostos com potencial antioxidante nos frutos em comparação à adubação solúvel convencional (antocianinas, acúmulo relativo do transcrito UFGT e ácido L-ascórbico). A avaliação desta adubação alternativa em diferentes níveis de estresse hídrico demonstrou haver um maior incremento nos compostos fenólicos e atividade antioxidante, evidenciando a viabilidade desta estratégia de biofortificação, sendo que o nível 1 de estresse apresentou menores perdas em relação aos parâmetros fotossintéticos avaliados e redução da produção de frutos em relação ao nível de estresse mais severo avaliado (nível 2). Os resultados obtidos neste estudo corroboram o potencial de uso da adubação alternativa avaliada no cultivo do morangueiro, sendo necessária ainda a busca por um nível de estresse hídrico que além de incrementar compostos com potencial antioxidante, conforme observado neste estudo, não afete significativamente o desenvolvimento das plantas e a produtividade da cultura do morangueiro, bem como sirva como uma técnica eficaz de biofortificação. / The biofortification of crops is a strategy that has been studied and explored in order to improve feeding supply by increasing or improving food quality of food to reduce malnutrition and offer healthier foods. Among the techniques used to perform the biofortification, the use of fertilization and, more recently, the application of controlled abiotic stresses have been applied, showing that the application of these techniques may result in the accumulation of antioxidant compounds with potential interest for promotion of human health , without significantly harming crop development and productivity. The strawberry fruits , whose specific sensorial features make its increasingly high consumption, naturally present in its composition, with compounds with potential antioxidant such as vitamin C, phenolic acids and anthocyanins, which may have their contents modified in order to improve their antioxidant potential in addition to its defense functions under stress conditions. On the other hand, the strawberry crop has a high rate of sensitivity to water and nutritional deficits; main fertilizer strategies for this crop typically uses soluble sources of nutrients, which can result in soil damage, nutritional imbalance, leaching and contamination of groundwater. In this study, strawberry plants were subjected to different levels of water stress and to an alternative fertilizer matrix composed of tung presscake and rock powder, and evaluated to biochemical, physiological and molecular variables. The results showed that the alternative fertilization has potential for use as an agricultural input as long as it has increased the fruit yield (23.79 % related to the soluble fertilizer treatment) and also improved the accumulation of Lascorbic acid, anthocyanins and the related expression of the UFGT gene compared to the soluble fertilizer strategy. The evaluation of the same alternative fertilizer at two different levels of water stress showed a significant increase in total phenolic compounds and antioxidant activity, demonstrating the feasibility of this biofortification strategy. In the level 1 of drought stress the results showed an increase in the photosynthetic parameters and in the fruit productivity related to the more severe level of stress (level 2). The results of this study support the potential use of the alternative fertilization evaluated for the strawberry crop, although that remains necessary studies to find out drought stress level that besides increasing compounds with antioxidant potential, as observed in this study, do not affect significantly the plant growth and yield of strawberry crop, to be used as an biofortification technique.

Although mango (Mangifera indica L.) has been studied for many years, numerous problems still elude researchers. The objectives of the current trials were to study the effects of some cultural practices (fruit thinning, panicle/ bud/ renewal/ post-harvest pruning) and chemicals (Corasil.E, potassium nitrate/urea, paclobutrazol) on various vegetative, floral, yield and quality parameters. The study meant to address problems of both South African and Ethiopian mango growers. The thinning (on ‘Sensation’) and pruning (on ‘Tommy Atkins’ and ‘Keitt’) experiments were conducted for two seasons (2001-2003) at Bavaria Fruit Estate in South Africa. Effects of Paclobutrazol and Potassium nitrate were studied on ‘Tommy Atkins’ during 2002-2003 season at Upper Awash Agro-industry Enterprise in Ethiopia. Complementary effects of paclobutrazol and potassium nitrate on floral induction were studied in growth chamber experiments at the experimental farm of University of Pretoria on ‘Tommy Atkins’ and ‘Keitt’ mango. Where fruit on ‘Sensation’ were thinned to one and two fruit per panicle, a significant increase was obtained for most of the fruit quantitative parameters. The treatments where one fruit and two fruit per panicle were retained and 50% panicles removed, produced a significant increase in size of the fruit, fruit qualitative parameters and fruit retention percentage. Corasil.E produced very small sized fruit with a considerable percentage of “mules” (fruit without seed). Trees subjected to severe thinning intensities showed earlier revival of starch reserves and better vegetative growth. Applications of paclobutrazol (1- (4-chlorophenyl) –4,4-dimethyl-2- (1,2,4- triazol-1-yl) pentan-3-ol) at rates of 5.50 and 8.25 g a.i. per tree, both as a soil drench and spray applications, on ‘Tommy Atkins’ mango were effective in suppressing vegetative growth as compared to the control. Consequently, the trees from these treatments had higher total non-structural carbohydrate in their shoots before flowering which led to higher results of percentages of shoots flowering, number of panicles produced, percentages of hermaphrodite flowers, yield and quality of the fruit. Trees that received panicle pruning (during full bloom) treatment at the point of apical bud attachment, were observed to be induced for synchronized re-flowering and also attained more fruit per panicle. On the other hand, trees on which renewal pruning (early in the season) and post-harvest pruning (especially for early cultivars) treatments were applied, have been observed for the development of an adequate number of productive inflorescences. Post-harvest pruning treatments also resulted in greater vegetative growth on both cultivars. The responses to pruning treatments were greater especially in ‘Tommy Atkins’ than ‘Keitt’. The trend for the interaction of duration and chemicals in Tommy Atkins and Keitt mango cultivars revealed the possible floral induction complementary effect of PBZ after the trees were induced only for 15 days at 10/15 oC temperature. Higher potassium nitrate concentrations especially in combination with urea (5 litre solution of 4% KNO3+0.5 g urea tree-1 and 5 litres of 4% KNO3+1 g urea tree-1 ) produced higher results for most of the flowering and yield parameters in ‘Tommy Atkins’. / Thesis (DPhil (Horticulture))--University of Pretoria, 2006. / Plant Production and Soil Science / unrestricted

Chez la tomate, l'amélioration pour la qualité du fruit est rendue difficile par la multiplicité et la complexité des caractères. La cartographie de QTL a permis la caractérisation génétique de ces caractères. L'objectif est maintenant d'identifier les gènes sous-jacents aux QTL. Nous avons utilisé la cartographie par déséquilibre de liaison (DL) dans ce but. Pour éviter les fausses associations entre caractères et polymorphismes moléculaires, la structure génétique a été prise en compte dans l'analyse. La tomate cultivée montre un faible niveau de diversité génétique, ce qui réduit la résolution de cartographie. Le génome de la tomate de type cerise est décrit comme une mosaïque entre celui de la tomate cultivée et de l'ancêtre sauvage. Ce mélange devrait augmenter la résolution des études d'association. Nous avons utilisé une « core collection » focalisée sur des accessions de type cerise pour valider la région génomique contenant un QTL pour le nombre de loges. Deux mutations sont associées avec le caractère. Ces deux SNP ont évolué différemment du reste du chromosome 2, en subissant une sélection balancée qui témoigne de l'augmentation de la diversité morphologique lors de la domestication. L'étude, focalisée sur le chromosome 2, a permis d'analyser l'étendue du DL en fonction de la distance génétique et physique. Des associations, entre polymorphismes et phénotypes étudiés, ont été détectés avec des méthodes prenant en compte la structure génétique. Nous avons montré l'intérêt d'utiliser la structure en mosaïque du génome des accessions de type cerise pour surmonter les limitations de résolution dans les analyses d'associations chez une espèce cultivée autogame. / In Tomato (Solanum lycopersicum), breeding for fruit quality is difficult due to the multiplicity and complexity of the traits. QTL mapping has allowed the genetic characterization of these traits. One of the challenges is now to identify the genes underlying these QTLs. Following this aim, we used linkage-disequilibrium (LD) mapping. To avoid hazardous associations between traits and polymorphisms, the genetic structure has to be taken into account for LD mapping. Cultivated tomato showed low genetic diversity reducing mapping resolution. Cherry type tomato genome is described to be admixture between cultivated tomato and its wild ancestor. Such admixture may increase resolution of association mapping. We used a core collection focused on cherry type accessions to validate a candidate gene for a fruit locule-number QTL. We found that two single nucleotide polymorphisms (SNP) were highly associated with the trait. These two SNP evolved differently from the rest of the chromosome 2. They underwent a balanced selection which testifies a selection for fruit morphology diversity by human. Association mapping, focused on whole chromosome 2, allowed us to assess the extent of linkage disequilibrium over genetic and physical distances. Associations of polymorphisms with phenotypes were detected with structured association methods. We thus showed efficiency of genome admixture to overcome the low-resolution limitation of association mapping for an inbred crop. We validated previously identified QTLs and found associations with new QTLs and new candidate genes. An evolutionary model including bottleneck and gene flow between wild and domesticated forms is also presented.

L’acide ascorbique (AsA) est un antioxydant essentiel à la fois pour l’homme et les végétaux. L’AsA provenant des plantes représente la source principale de vitamine C dans l’alimentation quotidienne. Au-delà de son impact nutritionnel, augmenter la teneur en AsA dans le fruit de tomate serait susceptible d’influencer la qualité des fruits après la récolte, en termes de conservation mais également de résistance à des pathogènes. Bien que le métabolisme de l’AsA soit bien caractérisé, les mécanismes impliqués dans sa régulation restent jusqu'à présent peu compris. Des études récentes menées sur des feuilles d’Arabisdopsis thaliana montrent que certaines protéines seraient capables de réguler la teneur en AsA, en agissant au niveau transcriptionnel ou post-transcriptionnel. A ce jour, ce type de régulation n’a pas été encore décrit chez les fruits. Dans ce but, une approche de génétique directe a été développée afin d’étudier les mécanismes impliqués dans la régulation de la teneur en AsA et ceci dans le fruit de tomate (Solanum lycopersicum). L’analyse d’une population de mutants EMS de tomate Micro-Tom a permis l’identification de lignées de mutants présentant des teneurs en AsA de 2,5 à 4 fois plus importantes que celles observées dans les fruits de tomate sauvage. La caractérisation de ces lignées a conduit à des résultats prometteurs pour l’étude de la qualité des fruits après la récolte. Une stratégie de NGS-mapping a permis l’identification des mutations causales responsables du phénotype AsA observé. Ainsi, le criblage de mutants EMS a permis la découverte de nouvelles protéines inattendues, permettant de confirmer au niveau moléculaire l’existence d’une interaction directe en la signalisation lumineuse et la régulation de la voie de biosynthèse de l’AsA. / The ascorbic acid (AsA) is an essential antioxidant in both plants and humans. Plant-derived AsA is the major source of vitamin C in the human diet. In addition to its effect on tomato nutritional value, increasing tomato AsA content would likely affect postharvest storage and resistance to pathogens of the fruit. While AsA metabolism is well characterized, the mechanisms involved in its regulation remain poorly understood. Recent studies in Arabidopsis leaves indicate that few regulatory proteins can regulate this pathway at transcriptional and post-transcriptional levels. Still nothing equivalent has been described in fruits. In that aim, a forward genetic approach has been carried out to investigate the regulation of AsA in tomato (Solanum lycopersicum) fruit. The screening of an EMS tomato mutant population in the miniature cultivar Micro-Tom for identifying mutant lines with AsA-enriched fruits was done. Among the 500 M2 mutant families screened, four mutant lines with higher AsA content ranging from 2.5 to 4 fold were selected. These mutant lines have been characterized for postharvest traits quality and showed promising results. A method based on NGS-mapping allowed the identification of the putative AsA-enriched related gene. Thus, the screening of EMS mutants led to original findings such as the discovery of new unexpected proteins regulating AsA in plants, and particularly in fruits. Our work confirms at the molecular level the direct interaction between light signaling component and the regulation of the AsA biosynthesis pathway.