Certains champignons sont très dommageables pour les plantes mais aussi pour la conservation après récolte des produits végétaux. Les restrictions réglementaires concernant l’utilisation des fongicides nécessitent de trouver des solutions alternatives. L'amélioration de la résistance des plantes en utilisant des méthodes physiques, comme les rayonnements UV, peut présenter une alternative prometteuse en association avec d’autres méthodes dans le cadre d’une protection intégrée des cultures. L'objectif de cette thèse a été d’étudier l’effet des rayonnements UV-C sur la sensibilité des plantes aux agents pathogènes. Les rayonnements UV-C ont été appliqués durant la culture, seuls ou en combinaison à des agents de biocontrôle, ou en post-récolte. Les expérimentations ont été menées sur deux espèces végétales : le fraisier et la tomate.Sur fraisier, des traitements UV-C à une dose de 1,70 kJ/m² entraînent une diminution systématique d'environ 20 % de la sensibilité des feuilles à Botrytis cinerea et diminuent jusqu’à 50 % le nombre de feuilles attaquées par Podosphaera aphanis, l’agent causal de l’oïdium. Chez la tomate, la protection des feuilles contre B. cinerea atteint 43 % avec une dose d’UV-C cumulée de 4,0 kJ/m². Ces mêmes traitements UV-C appliqués sur fruits réduisent la sensibilité des fraises vis-à-vis de Rhizopus de 75 % mais aucun effet n’est observé vis-à-vis de B. cinerea. Au contraire, sur fruits de tomate, la sensibilité est diminuée d'environ 63 % contre cet agent pathogène. Parallèlement, des tests biochimiques et gustatifs suggèrent que la qualité des fruits n’est pas significativement améliorée ni altérée par les expositions UV-C. Malgré un effet germicide marqué des rayonnements UV-C sur feuilles de fraisiers, aucun effet bénéfique de l’application de ces rayonnements sur le niveau d’efficacité d’agents de lutte biologique n’a été mis en évidence.Nos observations sont encourageantes pour envisager une utilisation de cette méthode dans un schéma de protection intégrée des cultures. Cependant, une compréhension claire de la façon dont les rayonnements UV-C sont perçus par les plantes et traduits en mécanismes de défense est nécessaire avant que leur utilisation ne soit recommandée sur le terrain. / Some fungi are very damaging during plant cultivation and also in post-harvest storage of products. Regulatory restrictions on fungicide use require alternative solutions. Improving plant resistance using physical methods, such as aplication of UV radiation, can be a promising alternative in association with other methods as part of an integrated pest management strategy. The objective of the present thesis was to study the effect of UV-C aplication on the sensitivity of plants to fungal pathogens. UV-C radiation was applied during plant cultivation, alone or in combination with biocontrol agents, or in post-harvest. Experiments were conducted on two plant species: strawberry and tomato.On strawberry plants, UV-C treatments at 1.70 kJ/m² result in a systematic 20 % decrease in leaves sensitivity to Botrytis cinerea and in a reduction by up to 50 % of the number of leaves infected by Podosphaera aphanis, the causal agent of powdery mildew. In tomato, leaves protection against B. cinerea reaches 43 % with a cumulative dose of 4.0 kJ/m². UV-C treatments applied on fruits reduce the strawberry sensitivity to Rhizopus by 75 % but no effect is observed against B. cinerea. On the contrary, sensitivity against B. cinerea is reduced by 63 % on tomato fruit. Biochemical and taste tests suggest that fruit quality is not significantly improved or altered by UV-C treatment. Despite a marked germicidal effect of UV-C radiation on strawberry leaves, it has no significant effect on the protective efficacy of biocontrol agents.Our observations are encouraging to consider the use of this tool in an integrated crop protection scheme. However, a clear understanding of how UV-C radiations are perceived by plants and their translation into defense mechanisms is necessary before their use is recommended in the field.

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.

Submitted by Gabriela Lopes (gmachadolopesufpel@gmail.com) on 2017-07-05T15:51:59Z No. of bitstreams: 2 license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) TESE silvana .pdf: 1176945 bytes, checksum: 524d27f394d80efa27a599fbe733e6f3 (MD5) / Approved for entry into archive by Aline Batista (alinehb.ufpel@gmail.com) on 2017-07-11T21:11:18Z (GMT) No. of bitstreams: 2 TESE silvana .pdf: 1176945 bytes, checksum: 524d27f394d80efa27a599fbe733e6f3 (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) / Made available in DSpace on 2017-07-11T21:11:18Z (GMT). No. of bitstreams: 2 TESE silvana .pdf: 1176945 bytes, checksum: 524d27f394d80efa27a599fbe733e6f3 (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) Previous issue date: 2017-01-30 / Conselho Nacional de Pesquisa e Desenvolvimento Científico e Tecnológico - CNPq / O tomateiro é cultivado em praticamente todas as regiões brasileiras. Dentre os diversos tipos de tomates existentes, o minitomate vem se destacando, devido às suas características produtivas, pois além de ser bastante atrativo e saboroso, possui alto valor agregado estimulando os produtores a investirem no cultivo dessa hortaliça. O cultivo de minitomate vem sendo realizado, principalmente, em ambiente protegido, como uma forma de minimizar as perdas em produção e qualidade de frutos, além de proporcionar a produção antecipada ou fora de safra e assim proporcionar maior retorno ao produtor do que o obtido com o cultivo convencional a céu aberto. Assim, os objetivos do trabalho foram: avaliar o efeito da variação da densidade de plantio e do raleio de inflorescências sobre a produção e partição de massa seca da planta e as características produtivas de minitomateiros dos tipos cereja e grape em duas épocas de cultivo, em sistema hidropônico; e estudar os componentes de rendimento, e as características físico-químicas relacionadas à qualidade organoléptica de duas cultivares de minitomates, observando a influência da adoção de uma alta densidade de plantio em dois ciclos de cultivo em sistema hidropônico. Para isso, dois experimentos foram realizados em condições de estufa plástica, no Campus da Universidade Federal de Pelotas, RS. A semeadura foi efetuada no dia 24 de novembro de 2012 para o ciclo de verão-outono (2012/2013), e para o cultivo de primavera-inverno (2013/2014) foi realizada em 26 de agosto de 2013. O ciclo da cultura foi de 183 dias no cultivo de verão-outono e 298 dias no cultivo de primavera-inverno, contados a partir do transplante. As plantas foram tutoradas por fita de ráfia presa na linha de arame disposta 3,0 m acima da linha de cultivo e sustentada pela estrutura da estufa. A condução foi com haste única, fazendo-se a desbrota das hastes laterais periodicamente. Objetivando-se prolongar o período de colheita, quando as plantas atingiram a altura do arame, a base dos caules foi sistematicamente desfolhada e rebaixada, seguindo a condução do tipo “carrossel holandês”. As plantas foram avaliadas em cinco densidades de plantio: 2,6; 2,9; 3,4; 3,9; e 4,7 plantas m-2 no experimento de verão-outono; para o experimento de primavera-inverno as densidades estudadas foram 2,9; 3,9; 4,7; 5,9 e 7,8 plantas m-2 . Após a emissão das inflorescências, foi feito o raleio das mesmas nas subparcelas determinadas, deixando-se 20 flores por racemo. O crescimento foi 7 quantificado por meio da determinação da biomassa aérea (massa fresca e seca) das plantas durante o ciclo produtivo e a acumulada ao final de cada experimento, sendo incluídos os frutos colhidos durante o processo produtivo, bem como as folhas provenientes de desfolhas antecipadas e as frações de desbrota. Para as avaliações das características físico-químicas, adicionalmente, aos experimentos foram escolhidas duas densidades de plantio: 3,4; e 4,7 plantas m-2 no experimento de verão-outono; e 2,9; e 7,8 plantas m-2 no experimento de primavera-inverno. Foram realizadas avaliações físico-químicas dos frutos, como o teor de sólidos solúveis (ºBrix), acidez titulável, relação ºBrix/acidez (‘ratio’), açúcares redutores, ácido ascórbico, pH, compostos fenólicos, luminosidade (l*), vermelho (+a*), amarelo (+b*), Hue, licopeno, β-caroteno, ácido clorogênico, e a atividade antioxidante. Em relação ao aumento da densidade de plantio observou-se que houve uma redução no crescimento de todos os órgãos, no tamanho de frutos e na produção de frutos por planta, sem afetar a proporção de massa seca alocada nos frutos. Porém, aumenta linearmente o número de frutos colhidos e a produtividade por unidade de área. Já, o raleio de flores não afeta o crescimento dos frutos e a partição de massa seca para estes órgãos em ambas as cultivares e ciclos. Porém, em ciclo longo, de primaverainverno, aumenta o tamanho e a produção dos frutos; e em ciclo curto, de verãooutono, não afeta as características produtivas de ambas as cultivares. Recomendase a adoção da densidade de plantio de 2,9 plantas m-2 para ambas as cultivares em ciclo mais curto, de verão-outono; e as densidades de 2,9 e de 3,9 plantas m-2 , respectivamente, para ‘Cereja Coco’ e ‘Grape Dolcetto’ em ciclo longo de primaverainverno. A prática do raleio, do ponto de vista fitotécnico, é recomendável para ambas as cultivares em ciclo de primavera-inverno. Em relação às características físicas e químicas relacionadas à qualidade organoléptica de frutos de minitomates com adoção de uma maior densidade de plantio, indicam que os componentes do rendimento são, de forma geral, semelhantes para os diferentes ciclos estudados e dependem, principalmente, do híbrido avaliado. O aumento da densidade de plantio reduz o tamanho dos frutos e aumenta o número e a produtividade de frutos por unidade de área em ambos os híbridos. O híbrido ‘Grape Dolcetto’ apresenta-se, com melhor qualidade, e é mais afetado pela adoção de uma maior densidade de plantio do que o híbrido ‘Cereja Coco’. O emprego de uma alta densidade de plantio não afeta as características de coloração dos frutos das duas cultivares. / The tomato is grown in almost all regions of Brazil. Among the different types of tomatoes, mini tomato has stood out due to their productive characteristics, as well as being very attractive and tasty, has high added value by encouraging producers to invest in the cultivation of this vegetable. The mini tomato cultivation is being carried out mainly in a protected environment, as a way to minimize losses in production and fruit quality, and provide the anticipated production or out of season and thus provide greater returns to producers than that obtained with conventional cultivation in the open. The objectives of the study were to evaluate the effect of variation of planting density and thinning of inflorescences on the production and dry matter partition of the plant and the production characteristics of mini tomato types cherry and grape in two growing seasons in hydroponic; and study the yield components, and the physical and chemical characteristics related to the organoleptic quality of two cultivars of mini tomato, noting the influence of adopting a high density planting in two crop cycles hydroponically. For this, two experiments were conducted in greenhouse conditions, on the campus of the Federal University of Pelotas, Brazil. Sowing was performed on November 24, 2012 to the summer-autumn cycle (2012/2013), and the spring-winter crop (2013/2014) was held on 26 August 2013. The crop cycle it was 183 days in the summer-autumn crop and 298 days in the spring-winter crop, counted from the transplant. The plants were stood by raffia tape, fixed in the line willing 3.0 m above the cultivation line and sustained by the greenhouse structure. Driving was single stem, becoming the thinning of the side rods periodically. Aiming to prolong the harvest period, when the plants reached the height of the wire, the base of the stems was systematically leafless and lowered, following the driving of the "Dutch Carousel". The plants were evaluated in five planting densities: 2.6; 2.9; 3.4; 3.9; and 4.7 m-2 plants in the summer-autumn experiment; for spring-winter experiment densities studied were 2.9; 3.9; 4.7; 5.9 and 7.8 plants m-2 . After the issuance of inflorescences was done thinning the same in certain subplots, leaving 20 flowers per raceme. Growth was quantified by 9 determining the biomass (fresh and dry weight) of the plants during the production cycle and accumulated at the end of each experiment, and included the fruits harvested during the production process as well as the leaves from early defoliation and the fractions of thinning. For evaluations of physical-chemical characteristics, in addition, the experiments were chosen two planting densities: 3.4; and 4.7 m-2 plants in the summer-autumn experiment; and 2.9; and 7.8 plants m-2 in spring-winter experiment. Physical and chemical evaluations of the fruits were carried out, such as soluble solids (° Brix), titratable acidity, ratio Brix / acidity (TA ratio), reducing sugars, ascorbic acid, pH, phenolics, lightness (L *), red (+ a *), yellow (+ b *), Hue, lycopene, β-carotene, chlorogenic acid, and antioxidant activity. Regarding the increase in planting density was observed that a reduction in growth of all organs in fruit size and fruit yield per plant, without affecting the dry mass proportion allocated in fruits. However, linearly increases the number of harvested fruit and the productivity per unit area. Already, the thinning of flowers does not affect the growth of fruit and dry matter partition for these organs in both cultivars and cycles. However, in long cycle, spring and winter, increases the size and production of fruits; and short cycle of summer-autumn, does not affect the traits of both cultivars. It is recommended the adoption of the 2.9 plants planting density m-2 for both varieties in shorter cycle of summer-autumn; and densities of 2.9 and 3.9 plants m-2 , respectively, to 'Cherry Coco "and" Grape Dolcetto' in long cycle of spring-winter. The practice of thinning the fitotécnico point of view, it is recommended for both cultivars in spring-winter cycle. In relation to physical and chemical characteristics related to the organoleptic quality of fruit mini tomato with the adoption of a higher plant density, indicate that yield components are, in general, similar to the different cycles studied and depend mainly on the rated hybrid . Increased planting density reduces fruit size and increase the number and fruit yield per unit area in both hybrids. The hybrid 'Grape Dolcetto' presents itself with better quality and is more affected by the adoption of a higher plant density than the hybrid 'Cherry Coco'. The use of a high planting density does not affect the fruits of staining characteristics of both cultivars.

L’amélioration de la qualité du fruit de tomate dépend largement de la variation génétique. A la suite de la domestication et de la sélection moderne, la diversité moléculaire chez la tomate a été profondément réduite, limitant les possibilités d’amélioration. De nouveaux marqueurs moléculaires révélant les polymorphismes nucléotidiques (SNP) constituent des outils précieux pour saturer les cartes génétiques et identifier des QTL (quantitative trait loci) et des associations chez une espèce peu polymorphe comme la tomate. Les objectifs de cette étude étaient de caractériser la diversité génétique de la tomate au niveau moléculaire et de tenter d’identifier des QTL, des gènes et des protéines responsables de la variation de caractères de qualité du fruit. Pour cela, trois études indépendantes ont conduit à (1) la découverte de nouveaux marqueurs SNP, (2) leur utilisation en génétique d’association et (3) l’analyse de la diversité du protéome en relation avec des caractères physiologiques du fruit.Dans la première étude, nous avons comparé deux plateformes de reséquençage pour reséquencer des zones ciblées couvrant environ 0.2% du génome de deux accessions contrastées. Plus de 3000 SNP sont été identifiés. Nous avons ensuite validé 64 SNPs en développant des marqueurs CAPS. Nous avons ainsi montré l’intérêt des techniques de reséquençage pour la découverte de SNP chez la tomate et produit des marqueurs simples qui peuvent être utiles pour caractériser de nouvelles ressources.Nous avons ensuite développé un ensemble de 192 SNPs et génotypé une collection de 188 accessions comportant des accessions cultivées, des types “cerise” et des formes sauvages apparentées et recherché des associations avec 10 caractères de qualité du fruit. Une quarantaine d’associations a été détectée dans des régions où des QTL avaient été préalablement identifiés. D’autres associations ont été identifiées dans de nouvelles régions. Nous avons ainsi confirmé le potentiel de la génétique d’association pour la découverte de QTL chez la tomate. Finalement une approche combinant l’analyse du protéome, du métabolome et de traits phénotypiques a été mise en oeuvre pour étudier la variabilité naturelle de la qualité du fruit de huit lignées contrastées et de quatre de leurs hybrides, à deux stades de développement (expansion cellulaire et orange-rouge). Nous avons identifié 424 spots protéiques variables en combinant électrophorèse bidimensionnelle et nano LC MS/MS et construit une carte de référence du protéome de fruit de tomate. En parallèle, nous avons mesuré la variation de teneurs en 34 métabolites, les activités de 26 enzymes et cinq caractères phénotypiques. La variabilité génétique et les modes d’hérédité ont été décrits. L’intégration des données a été réalisée par construction de réseaux de corrélations et régression sPLS. Plusieurs associations ont été détectées intra et inter niveau d’expression, permettant une meilleure compréhension de la variation de la qualité des fruits de tomate / Fruit quality in tomato is highly dependent on genetic variation. Following domestication and modernbreeding, molecular diversity of tomato has been strongly reduced, limiting the possibility to improvetraits of interest. New molecular markers such as single nucleotide polymorphisms (SNP) constituteprecious tools to saturate tomato genetic maps and identify quantitative trait loci (QTL) andassociations in a poorly polymorphic species like tomato. The objectives of this study were tocharacterize tomato genetic diversity at the molecular levels and to try to identify QTLs, genes andproteins responsible for fruit quality traits in tomato. For this purpose, three independent studies wereconducted leading to the discovery of new SNP markers, their use for association study and finally theanalysis of proteome diversity in relation to physiological phenotypes. We first used two nextgenrationsequencing platforms (GA2 Illumina and 454 Roche) to re-sequence targeted sequencescovering about 0.2% of the tomato genome from two contrasted accessions. More than 3000 SNPswere identified between the two accessions. We then validated 64 SNPs by developing CAPS markers.We thus showed the value of NGS for the discovery of SNPs in tomato and we produced low costCAPS markers which could be used to characterize other tomato collections. A SNPlexTM arraycarrying 192 SNPs was then developed and used to genotype a broad collection of 188 accessionsincluding cultivated, cherry type and wild tomato species and to associate these polymorphisms to tenfruit quality traits using association mapping approach. A total of 40 associations were detected andco-localized with previously mapped QTLs. Some other associations were identified in new regions.We showed the potential of using association genetics in tomato. Finally, a new analytical approachcombining proteome, metabolome and phenotypic profiling were applied to study natural geneticvariation of fruit quality traits in eight diverse accessions and their four corresponding F1s at cellexpansion and orange-red stages. We identified 424 variable spots by combining 2-DE and nano LCMS/MS and built the first comprehensive proteome reference map of the tomato fruit pericarp at twodevelopmental stages from the 12 genotypes. In parallel, we measured the variation of 34 metabolites,26 enzyme activities and five phenotypic traits. A large range of variability and several inheritancemodes were described in the four groups of traits. Data integration was achieved through sPLS andcorrelation networks. Many significant associations were detected within level and between levels ofexpression. This systems biology approach provides better understanding of networks of elements(proteins, enzymes, metabolites and phenotypic traits) in tomato fruits

O Estado de São Paulo caracteriza-se como o principal produtor de pêssegos (Prunus persica (L.) Batsch) para consumo “in natura” do Brasil. Devido ao cultivo ser realizado em diferentes regiões e pelo uso de cultivares precoces e bem precoces, a maioria da safra ocorre na estação da primavera, antecipadamente à região Sul do Brasil. Um dos problemas decorrentes do plantio de pessegueiros em regiões mais quentes, como o Estado de São Paulo, foi o aumento considerável da ferrugem (Tranzschelia discolor). A poda verde, realizada após a colheita dos frutos, mostra-se como um dos métodos culturais utilizados pelos produtores para o manejo desta doença. O trabalho de pesquisa objetivou verificar o efeito de intensidades de poda verde após a colheita, no desenvolvimento do pessegueiro e na severidade de ferrugem. O trabalho experimental foi realizado no Campus “Luiz de Queiroz” da Universidade de São Paulo, em Piracicaba, Departamento de Produção Vegetal, sendo composto dos seguintes tratamentos: T1: poda verde de intensidade leve (PL) e T2: poda verde de intensidade drástica (PD). A área útil do ensaio foi de 345,6 m2, constituída de 96 plantas conduzidas no espaçamento de 3 x 1,2 m. O delineamento experimental utilizado foi inteiramente ao acaso, constituído de 2 tratamentos e 12 repetições. As variáveis analisadas foram: florescimento efetivo; densidade de brotação; crescimento dos ramos; desenvolvimento de frutos; qualidade dos frutos (massa, tamanho, coloração, firmeza de polpa, teor de sólidos solúveis); severidade de ferrugem e determinação das concentrações de carboidratos solúveis em raízes e ramos em diversos períodos. De acordo com os dados obtidos pelo presente trabalho, pode-se concluir que para a cultivar Flordaprince, nas condições de Piracicaba-SP, quanto mais intensa for a poda verde realizada em outubro: menor é a concentração de carboidratos solúveis nas raízes no período de dormência; maior é o crescimento de ramos após a sua execução; menor é a fixação de frutos no próximo ciclo; menores são os teores de sólidos solúveis nos frutos. A intensidade da poda verde realizada nas mesmas condições, não interfere: na concentração de carboidratos solúveis em ramos; no florescimento efetivo, densidade de brotação e crescimento de ramos após a poda seca; no desenvolvimento, na massa, na coloração e na firmeza de frutos; na severidade de ferrugem em folhas de pessegueiro. / Sao Paulo State has the major peach production area (Prunus persica (L.) Batsch) for fresh market in Brazil. It is characterized by early-maturing production comparing to southern states of Brazil, with harvest taking place from September to February due to the use of early-season varieties and different production areas in a warmer climate. Peach rust Tranzschelia discolor is a disease affecting peach production in Sao Paulo State and it is favored by warmer and humid conditions especially between September and April. After harvest, practices that delay peach leaf senescence are necessary because this is the period of reserve carbohydrates accumulation for next season. Drastic pruning after harvest is an important rust control method leading to new shoot sprouting and resuming vegetative growth and bud differentiation for next season. This research evaluated the effect of different intensity levels of green pruning after harvest in the development of peach trees and the rust severity. in early-maturing peach cultivar. Experimental work was carried out at “Luiz de Queiroz” campus of University of Sao Paulo, in Piracicaba, Brazil. The following treatments were used: T1 – low pruning (LP) and T2 – drastic pruning (DP), using 345,6 m2 of area with 96 plants in 3 m x 1,2 m spacing. Experimental arrangement used was total randomized plots, with 2 treatments and 12 repetitions. Biometric data collected were: effective blossom, shoot density, stem length, fruit development and quality (fruit weight, diameter, color, pulp firmness and soluble solids concentration), rust severity and total soluble carbohydrate concentrations in roots and stems. In agreement with the data obtained by the present work, it can be ended that for to cultivate Flordaprince, in the conditions of Piracicaba-SP, the more intense it is the green pruning accomplished in october: minor is the concentration of soluble carbohydrates in the roots in the dormancy period; larger is the stem length after his execution; minor is the fixation of fruits in the next cycle; minor are the concentrations of soluble solids in the fruits. The intensity of the green pruning accomplished in the same conditions, it doesn't interfere in the concentration of soluble carbohydrates in stems; in the effective blossom; in the shoot density; in the stem lenght after the dry pruning; in the development; weight, color and the pulp firmness of fruits; in the rust severity in the peaches tree leaves.

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.

La qualité du fruit est un critère incontournable de sélection chez les Rosacées fruitières, et l’acidité constitue une composante majeure de la qualité organoleptique. Toutefois, les mécanismes physiologiques et moléculaires contrôlant l'acidité des fruits restent mal connus. Chez le pêcher, le caractère non acide du fruit est contrôlé par le locus D. Une descendance F2 de 208 individus issus d'un croisement entre une variété de pêche non acide ‘Ferjalou Jalousia®’ et une variété de nectarine normalement acide, ‘Fantasia’ (JxF) a été analysée pour différents caractères agronomiques dont l’acidité du fruit. Cette descendance a servi à la réalisation d’une carte génétique et ainsi à la localisation du locus D sur le groupe de liaison 5 (GL5). Ce locus co-localise avec des QTL à effet majeur impliqués dans l’acidité titrable, le pH, la teneur en acides organiques ainsi que des QTL à effet plus faible pour la teneur en sucres solubles. De nombreux gènes candidats impliqués dans la synthèse des acides organiques, la dégradation et le stockage vacuolaire avaient été précédemment étudiés. Cependant, aucun gène candidat n’a encore été cartographié dans la région du locus D, excluant ainsi leur rôle direct dans le contrôle de l’acidité du fruit. Ceci s’explique par la complexité des voies métaboliques des acides organiques et par l’implication de transporteurs, de canaux et de pompes à protons qui rendent l'identification du ou des gène(s) associés au locus D plus complexe par une approche gène candidat. Par conséquent, une approche de clonage positionnel a été menée dans la présente étude afin d’identifier le ou les gène(s) intervenant dans le contrôle de l’acidité du fruit chez le pêcher dans le but de comprendre les mécanismes moléculaires et physiologiques sous-jacents. La recherche de marqueurs liés au locus D a été réalisée par BSA-AFLP. Trente quatre marqueurs AFLP ont été cartographiés sur le GL5 et les six marqueurs les plus proches ont été convertis en marqueurs SCAR codominants. Une carte génétique fine de la région contenant le locus D a ensuite été réalisée à partir d’une descendance F2 élargie à 1 718 individus et à l’aide des six marqueurs SCAR et de trois marqueurs microsatellites précédemment cartographiés dans cette région. L’ensemble des données de génotypage et de phénotypage des individus ayant subi un événement de recombinaison dans la région du locus d’intérêt, a permis la localisation précise du locus D dans un intervalle de 0,4 cM. En parallèle, une banque BAC d’une couverture estimée à 15 fois la taille du génome haploïde du pêcher a été réalisée et son criblage a permis d’évaluer le rapport distance physique/distance génétique dans cette région à 250 kb/cM. Après deux étapes de marche sur le chromosome, une carte physique de la région a été construite en intégrant 16 marqueurs issus du séquençage d’extrémités de BAC. Un clone BAC de 98 kb contenant l’allèle D et un autre de 78 kb contenant l’allèle d ont été séquencés. L’annotation des séquences des deux allèles a mis en évidence onze gènes candidats. De nouveaux marqueurs développés à partir des séquences de ces deux BAC ont ensuite permis de préciser la localisation du locus d’intérêt dans un intervalle de 16 kb. Dans cette région deux gènes ont été identifiés : un gène de résistance et un gène codant pour un transporteur. Une approche transcriptionnelle a été initiée en complément du clonage positionnel afin de fournir un premier élément pouvant confirmer l’implication d’un ou plusieurs gène(s) candidat(s) positionnel(s) dans l’acidité du fruit chez le pêcher. / Acidity is an essential component of the organoleptic quality of fleshy fruits. However, the physiological and molecular mechanisms that control fruit acidity remain unclear. In peach low-acidity is determined at the D locus by the dominant allele. A peach progeny of 208 F2 individuals obtained from a cross between ‘Ferjalou Jalousia®’ (a low-acid peach) and ‘Fantasia’ (a normally acid nectarine) varieties (JxF) was analyzed for several agronomical traits. This peach F2 progeny segregating for several mendelian traits, was analyzed for fruit quality traits including fruit acidity and used for the construction of a genetic linkage map. The D locus was mapped to the proximal end of linkage group 5 (LG5) and co-localized with major QTLs involved in the control of fruit pH, titratable acidity and organic acid concentration and minor QTLs for sugar concentration. Several candidate genes involved in organic acids synthesis, degradation or vacuolar storage have previously been studied. However, none of these candidate genes were located on in the region of the D locus, excluding their direct role in the control of fruit acidity by the D locus. The complexity of organic acids metabolic pathways as well as the involvement of transporters and channels and related proton pumps has hampered, so far, the identification of the gene(s) associated to the D locus using a candidate gene approach. Thus, in order to investigate the molecular and physiological bases of fruit acidity in peach, a positional cloning strategy of the D locus was undertaken for the isolation of the gene(s) underlying this trait. Using a BSA-AFLP method, 34 AFLP markers were mapped to the LG5, and the six nearest markers were transformed into codominant SCAR markers. These SCAR markers and three previously mapped SSR markers were used to genotype an F2 segregating progeny extended to 1,718 F2 individuals. A high-resolution map of the D locus was realized after genotyping and phenotyping recombinant individuals. Using these recombinant plants we delimited the D locus to a genetic interval of 0.4 cM. We also constructed a peach BAC library with a covering estimated at 15 x the peach haploid genome. The screening of the BAC library with tightly linked markers indicated that 1 cM corresponds to 250 kb at the vicinity of the D locus and allowed the construction of the physical map in two walks integrating 16 markers obtained from the BACends sequences. Two BAC clones harbouring the D locus were identified and sequenced; one BAC clone of 98 kb containing the D dominant allele and another one of 78 kb containing the d recessive allele. Eleven predicted genes were found in the sequenced region. A new set of markers was developed which allowed the localization of the D locus in a 16 kb interval. In this region, two genes were identified: a resistance gene and a gene encoding for a transporter. A transcriptional approach was initiated in addition to the positional cloning strategy to provide a first element which could confirm the involvement of one or more identified positional candidate gene(s) in the control of peach fruit acidity.

The South African fresh fruit industry is a significant exporter, accounting for approximately 45% of the country’s agricultural exports. Of the total exported fruit in the 2005/06 season, 60% was subtropical fruit. However, certain physiological rind disorders such as mango lenticel damage and citrus rind pitting are frequently observed, reducing the commercial value of the fruit. This thesis deals with the epidemiology of these rind physiological disorders, in an attempt to obtain basic information that could serve as a guideline to predict and manage the fruit susceptibility to these disorders. The study further investigated the relative effects that certain pre-harvest factors have on the postharvest development of these disorders. Factors of particular interest were harvest maturity, climate and the mineral content of the fruit. Rind pitting is a physiological disorder of citrus that develops during storage. A study was conducted to investigate the relative effects that certain pre-harvest factors have on the post-harvest development of superficial rind pitting in ‘Benny Valencia’ oranges. Factors of particular interest were harvest maturity, climate and the mineral content of the fruit. In addition, trees were treated with two different formulations of nitrogen viz. limestone ammonium nitrate (LAN) and a slow release nitrogen fertilizer (Horticote®), during March 2006. The fruit were then sampled on a two-weekly basis over a period of three months. On each sampling date a set of quality related readings, such as juice sugar and titratable acid concentration were taken, after which the mineral concentration of the exocarp and mesocarp was measured. Fruit were also stored under export simulation conditions. The results indicate that fruit from trees that received additional N were more susceptible to rind pitting than those from control trees. Of the two N applications, fruit from trees that received slow release N were more susceptible to rind pitting than fruit from trees that received the LAN treatment. Another important observation made was that the nitrogen concentration of oranges from trees that received extra nitrogen fertilizer was lower than that from the controls. In addition, experimental fruit were smaller than control fruit. Fruit from trees that received the slow release nitrogen treatment were smallest. A sink/source hypothesis aimed at explaining this phenomenon has been formulated and is currently being investigated. A number of control mechanisms are also being explored. Mango lenticel damage is a serious defect that occurs on the rind of the fruit. This condition causes fruit to attain a speckled appearance and become unattractive to the buyer. Each season, the disorder reduces the packout of fresh fruit by about 16%. Several preharvest factors play a critical role in the postharvest development of lenticel damage. Preliminary studies have shown that the incidence of lenticel damage has some relationship to fruit moisture and fruit nutrient concentration, depending on which of these factors first achieve a critical threshold. A study was conducted to develop appropriate skin moisture content parameters to predict lenticel damage potential before harvest. The study further aimed to provide certain biological markers regarding appropriate nitrogen fertilization practices to reduce lenticel damage. To do this, two trials were conducted approximately a month before harvest. Firstly, a plastic ground cover to restrict water supply was laid under ‘Tommy Atkins’ trees at Numbi Estates in the Hazyview area of the Mpumalanga province, South Africa. Secondly, additional nitrogen was applied as three different formulations, viz. limestone ammonium nitrate (LAN), potassium nitrate (KNO3), and a slow release nitrogen fertilizer under trade name Horticote®, to two ‘Tommy Atkins’ and two ‘Keitt’ orchards at Bavaria Estates in the Hoedspruit area of the Limpopo province, South Africa. Fruit samples were harvested, packed and stored at different intervals after rain during January 2006. With regard to lenticel damage on ’Tommy Atkins’ fruit from Numbi, there was no significant difference between the control and plastic cover treatments. However, when compared to fruit from other localities, the Numbi fruit had the highest incidence of lenticel damage, followed by the conventional orchard at Bavaria. The Numbi fruit, which had the highest incidence of lenticel damage, also had the highest pulp and skin nitrogen concentration. Of the four treatments at Bavaria, the LAN treatment had the highest incidence of lenticel damage, but the pulp and skin nitrogen concentrations of this treatment were comparable with the other treatments. The organic fruit had significantly lower lenticel damage incidence and also had the lowest pulp and rind nitrogen concentrations. Similarly, ‘Keitt’ results showed that the intensity of lenticel damage was significantly higher in the orchard that received additional nitrogen in the form of LAN. From the results it was, however, not possible to formulate nitrogen-lenticel damage correlations. The study failed to prove the case for a direct relationship between the disorder and with nitrogen, as there were no significant or consistent correlations with nitrogen content. An interesting relationship was nevertheless observed between lenticel damage and the time of harvest before and after rainfall. The results indicated that both ‘Tommy Atkins’ and ‘Keitt’ fruit become more susceptible to lenticel damage when harvested a day after rainfall and this gradually reduces afterwards. The effect of rainfall in this regard and a sink-source hypothesis arising from these observations are also discussed. / Thesis (M.Sc.)-University of KwaZulu-Natal, Pietermaritzburg, 2008.

Thesis (MscAgric (Horticulture))--University of Stellenbosch, 2009. / ENGLISH ABSTRACT: Experiments were conducted to increase the percentage class one ‘Granny Smith’ and ‘Cripps’ Pink’ apples. ‘Granny Smith’ is the most widely grown apple cultivar in South Africa, but its profitability is compromised by the high incidence of sunburn, red blush and poor green colour development. ‘Cripps’ Pink’ is a very lucrative cultivar and producers are striving to maximise the production of fruit that qualify for export. Fruit technologists and growers are debating whether it is best to maximise class one fruit in ‘Cripps’ Pink’ by increasing total yield or by increasing fruit quality. The relationship between ‘Granny Smith’ canopy position and external fruit quality was investigated. Light exposure, peel temperature, green colour development, sunburn and red blush development was followed for individual fruit from the outer, intermediate and inner canopy. Dark green fruit were exposed to moderate to high light levels (25-50% full sun) during the first half of fruit development, similar to fruit that eventually developed sunburn and red blush. The difference came in during the latter half of fruit development when dark green fruit became shaded (3% full sun). Pale green fruit contained less chlorophyll due to consistent low light levels (2% full sun). Fruit at partially shaded canopy positions had a lower occurrence of sunburn and red blush than outside fruit and better green colour development than fruit from the heavily shaded inner canopy. Based on these data, pruning strategies and mulching were evaluated to alter canopy vigour and the light environment in such a way that green colour development is promoted and the occurrence of sunburn and red blush is reduced. In an older, vigorous orchard with a dense canopy, pruning was done to increase light distribution for green colour development and to induce more growth on the side of the trees that are prone to sunburn and red blush. Pruning improved green colour development without affecting sunburn or red blush. In a younger, non-vigorous orchard, pruning and mulching were used to invigorate the canopy to increase shading of fruit and thereby decrease sunburn and red blush. However, these treatments were not effective. Further research should focus on the use of shade nets, accompanied by rigorous pruning, to reduce sunburn and red blush while not decreasing green colour. Five different crop loads were established in an exceptionally high yielding (averaging over 100 ton·ha1) ‘Cripps’ Pink’ orchard by first the thinning of clusters, then the removal of small fruit and, finally, the selective removal of fruit from the shaded inner canopy. Treatments had no effect on iv fruit quality in the first season. The most severe thinning treatment increased the percentage class one fruit in the second season by increasing the number of fruit with adequate red blush. However, seen cumulatively, the higher crop loads yielded more class one fruit per hectare than the lower crop loads, without affecting reproductive and vegetative development or fruit storability. Producers should strive for the highest crop loads allowed by the fruit size limitations in cultivars that are not prone to alternate bearing / AFRIKAANSE OPSOMMING: Eksperimente is uitgevoer om die persentasie uitvoerkwaliteit ‘Granny Smith’ en ‘Cripps Pink’ appels te verhoog. ‘Granny Smith’ maak die grootste deel uit van appel aanplantings in Suid Afrika, maar die winsgewendheid daarvan word beperk deur `n hoë voorkoms van sonbrand, rooi blos en swak groen kleurontwikkeling. ‘Cripps’ Pink’ is `n baie winsgewende kultivar en produsente streef daarna om die persentasie uitvoerkwaliteit vrugte te maksimaliseer. Vrugte tegnoloë en produsente debatteer oor die wenslikheid daarvan om uitvoerkwaliteit vrugte te maksimeer deur totale produksie te verhoog of deur vrugkwaliteit te verbeter. Die verband tussen ‘Granny Smith’ draposisie in die blaredak en eksterne vrugkwaliteit is ondersoek. Ligvlakke, skiltemperatuur, groen kleurontwikkeling, sonbrand en rooi blos ontwikkeling is deur die loop van die seisoen gevolg vir individuele vrugte aan die buitekant, binnekant en intermediêre posisies binne die blaredak. Daar is gevind dat die donkerste groen vrugte, nes vrugte wat uiteindelik sonbrand en rooi blos ontwikkel het, blootgestel was aan matige tot hoë ligvlakke (25-50% vol son) gedurende die eerste helfte van vrugontwikkeling. Donker groen vrugte is egter oorskadu (3% vol son) tydens die tweede helfte van vrugontwikkeling. Vanweë konstante lae beligting (2% vol son) het binne vrugte min chlorofiel geakkumuleer en daarom is hierdie vrugte lig van kleur. Vrugte in gedeeltelike skadu ontwikkel min sonbrand en rooi blos in vergelyking met buite vrugte en toon beter groen kleurontwikkeling as vrugte in diep skadu binne die boom. Gegrond op bogenoemde resultate is die gebruik van snoei strategieë en deklae om die groeikrag en die ligomgewing van die boom te modifiseer, ten einde groen kleur ontwikkeling te bevorder en sonbrand en rooi blos te verminder, geëvalueer. In ‘n ouer, groeikragtige boord met ‘n digte blaredak is snoei gebruik om ligverspreiding te verbeter vir groen ontwikkeling en om meer groei te stimuleer aan die buitekant van die boom wat meer geneig is tot sonbrand en rooiblos. Groen kleur is wel verbeter, maar sonbrand en rooi blos is nie geaffekteer nie. In `n jonger, minder groeikragtige boord is ‘n deklaag aangebring en eenjarige lote getop, sodoende groei te stimuleer om sonbrand en rooi blos te verminder deur oorskaduwing van vrugte. Hierdie behandelings was egter nie effektief nie. Toekomstige navorsing moet fokus op die gebruik van skadunette tesame met ‘n nougesette snoei strategie om sonbrand en rooi blos te verminder sonder om groen kleur te verswak. Vyf verskillende vrugladings is geskep in `n uitermatig produktiewe (gemiddeld meer as 100 ton·ha-1) ‘Cripps’ Pink’ boord deur eers vrugtrosse uit te dun, gevolg deur die verwydering van klein vrugte en, laastens, die selektiewe verwydering van vrugte in die diep skaduwee van die binneste blaredak. Vrugkwaliteit is nie in die eerste seisoen nie deur oeslading geaffekteer nie. Die strafste uitdunbehandeling het wel die persentasie uitvoerbare vrugte in die tweede seisoen verhoog deur die aantal vrugte met voldoende rooi blos te vermeerder. Kumulatief gesien, het die hoër oesladings egter meer klas een vrugte per hektaar opgelewer sonder om die reproduktiewe en vegetatiewe ontwikkeling of die stoorvermoë van vrugte te affekteer. Produsente moet strewe na die hoogste oesladings wat toegelaat word deur vruggrootte beperkings in kultivars wat nie geneig is tot alternerende drag nie

Made available in DSpace on 2016-08-12T19:18:22Z (GMT). No. of bitstreams: 1 FernandoASA_TESE.pdf: 1416076 bytes, checksum: b1c98d86beac7a63692f0bd1fd27af60 (MD5) Previous issue date: 2010-04-29 / The Brazilian melon agribusiness is in expansion, reaching almost 500 thousand tons per year and making melon the main domestic fruit in both exported volume and value, with this activity being concentrated in the Brazilian Semiarid region. However, Brazil ranks only twelfth among the producing countries in area planted and production and the twentieth-third in productivity, demonstrating that there is still much to do on melon breeding and genetic resources of this crop. Thus, the objectives of this work were to estimate the genetic diversity of melon accessions collected from the traditional agricultural areas of the Brazilian Northeastern region by using descriptors for the fruit and microsatellite markers, and to study the nature of genotype vs. environment interaction and to estimate genetic parameters and gains by selection of melon families, in the Jaguaribe/Assú irrigation projects (Ceará and Rio Grande do Norte States, Brazil). The study of genetic diversity showed great variability among accessions, within and among the botanical groups, enabling advances in genetic improvement of fruit quality traits. Cluster analysis by fruit descriptors formed eight groups, without taxonomic criteria. The characters fruit longitudinal diameter, number of fruits per plant, cavity thickness and total soluble solids were descriptors that contributed most to the dissimilarity of the genotypes. The SSR markers amplified 41 alleles with average of 2.41 alleles and three genotypes per locus. A phylogenetic molecular analysis separated the accessions into 13 groups, also without taxonomic coherence in groups formed. The degree of association between genetic distance morpho-agronomic and molecular matrices was null. Then, there was no significant association between the descriptors and SSR markers, which was predictable due the number of distinct groups, the quantitative nature of the descriptors and the distribution of SSR markers in the genome. In the study of genotype vs. environment interaction, there was heterogeneity among the families for all traits. Heritability estimates in the combined analysis were consistently lower than those estimated for each environment. The simple part of G vs. E interaction was always above 99%, except for pulp firmness, with a predominance of the large complex part between the pairs of environments A1 and A3 and A2 and A3. The direct gains by selection were higher than the indirect gains for all traits in all environments evaluated. Gains were closer to the direct genetic gains when the selection was based on the average of the three environments. Estimates of genetic parameters associated with the simple nature of the family vs. environment interaction allowed genetic progress by simple breeding methods. As the genotype-environment interaction overestimates the coefficient of genetic variation and genetic variance among families in an environment, genotype assessments in more than one location are necessary since that selection is made considering the average of the families on the environments. Therefore, the potential of genetic improvement was demonstrated for the germplasm used in the study of genetic diversity as well as for the germplasm evaluated in the analysis of genotype-environment interaction. / O agronegócio do melão brasileiro tem se expandido bastante, alcançando quase 500 mil toneladas de frutos por ano e tornando o melão a principal fruta nacional, tanto em volume de exportação quanto em valor exportado, estando esta atividade concentrada no semiárido brasileiro. Contudo, o Brasil é apenas o décimo segundo país em produção e área plantada e vigésimo terceiro em produtividade, evidenciando que ainda existe muito por ser feito em termos do melhoramento e recursos genéticos desta cultura. Assim sendo, os objetivos deste trabalho foram estimar a divergência genética de acessos de meloeiro coletados em propriedades de agricultura tradicional do Nordeste brasileiro, tanto por descritores do fruto quanto por marcadores microssatélites e estudar a natureza da interação genótipo x ambiente (G x A) bem como estimar parâmetros genéticos e ganhos por seleção de famílias de melão, no polo Jaguaribe-CE/Assu-RN. O estudo de divergência genética mostrou grande variabilidade entre os acessos, entre e dentro dos grupos botânicos, possibilitando avanços no melhoramento genético dos caracteres de qualidade dos frutos. A análise de agrupamento por descritores do fruto formou oito grupos, sem critérios taxonômicos. Os caracteres diâmetro lateral, número de frutos por planta, espessura da cavidade e sólidos solúveis foram os descritores que mais contribuíram para a dissimilaridade dos genótipos. Os marcadores SSR amplificaram 41 alelos com média de 2,41 alelos e três genótipos por loco. A análise filogenética molecular separou os acessos em 13 grupos, também sem coerência taxonômica nos grupos formados. O grau de associação entre as matrizes de distâncias genéticas morfoagronômica e molecular foi nulo, não havendo associação entre os descritores e os marcadores SSR, o que era previsível devido ao número distinto de grupos, a natureza quantitativa dos descritores e a forma de distribuição dos marcadores SSR no genoma. No estudo de interação genótipo x ambiente, houve heterogeneidade entre as famílias para todas as características avaliadas. As herdabilidades estimadas nas análises conjuntas foram sempre inferiores àquelas estimadas em cada ambiente. A parte simples da interação G x A foi sempre superior a 99%, exceto para firmeza da polpa, com amplo predomínio da parte complexa entre pares de ambientes A1 e A3 e A2 e A3. Os ganhos diretos com seleção foram maiores do que os ganhos indiretos para todas as características, em todos os ambientes avaliados. Os ganhos foram mais próximos dos ganhos genéticos diretos quando se praticou a seleção pela média dos três ambientes. As estimativas de parâmetros genéticos associadas à natureza simples da interação família x ambiente permitem progresso genético por meio de métodos de melhoramento menos sofisticados. Como a interação genótipo x ambiente superestima o coeficiente de variação genético e a variância genética entre famílias em um ambiente, são necessárias avaliações dos genótipos em mais de um local, desde que a seleção seja praticada considerando a média das famílias nos ambientes. Portanto, ficou comprovado o potencial de melhoramento genético tanto no germoplasma utilizado no estudo de divergência genética quanto do germoplasma avaliado nas análises da interação genótipo x ambiente.