Made available in DSpace on 2015-04-09T12:28:12Z (GMT). No. of bitstreams: 0 Previous issue date: 2013-07-12Bitstream added on 2015-04-09T12:47:59Z : No. of bitstreams: 1 000819184.pdf: 195601 bytes, checksum: 56567545115d1021be4550fb5b30f4c9 (MD5) / Este estudo foi desenvolvido na Faculdade de Ciências Agrárias e Veterinárias (UNESP-FCAV), Câmpus de Jaboticabal- SP, com o objetivo de avaliar o modo de herança da resistência do melão ‘Gaúcho Redondo’ a Meloidogyne incognita. Para tanto, foi conduzido um experimento em delineamento em blocos casualizados, com três blocos e seis tratamentos, os quais envolveram as linhas parentais ‘Gaúcho Redondo’ (P1 resistente à M. incognita) e JAB 20 (P2 suscetível, resultado do programa de Melhoramento Genético da Cultura do Melão Rendilhado da UNESP-FCAV), assim como as gerações F1 (P1xP2), F2 (F1xF1), e retrocruzamentos (RC1P1 e RC1P2). Foram avaliadas plantas individuais após 70 dias da inoculação com o patógeno, por meio do fator de reprodução do nematoide (FR), calculado pela contagem do número de ovos e juvenis de segundo estádio, contido na suspensão de cada raiz processada, dividido pela população inicial. A hipótese de herança monogênica foi rejeitada ao nível de significância de 1% de probabilidade no teste do qui-quadrado (χ2), indicando que a resistência está sob controle de mais de um lócus gênico, o que foi confirmado pela análise quantitativa, que evidenciou a existência de seis genes envolvidos na herança da resistência ao nematoide. Houve predominância dos efeitos aditivos no controle da característica em estudo, o que permite resposta aos processos de seleção / This study was conducted at the College of Agriculture and Veterinary Sciences (UNESP-FCAV) in Jaboticabal-SP, in order to evaluate the mode of inheritance of resistance of melon 'Gaucho Round' to Meloidogyne incognita. Therefore, an experiment was conducted in randomized block design with three blocks and six treatments, which involved the parental lines 'Gaucho Round' (P1 resistant to M. incognita) and JAB 20 (P2 susceptible result of Breeding Program Culture Melon Tracery UNESP-FCAV), as well as the F1 (P1xP2), F2 (F1xF1) and backcross (RC1P1 and RC1P2). Individual plants were evaluated 70 days after inoculation with the pathogen through the nematode reproduction factor (FR), calculated by counting the number of eggs and second stage juveniles contained in the suspension of each root processed, divided by the initial population . The hypothesis of monogenic inheritance was rejected at a significance level of 1% probability in the chi-square (χ2), indicating that resistance is under the control of more than one gene locus, which was confirmed by quantitative analysis, which showed the existence of six genes involved in inheritance of resistance to nematodes. Predominance of additive effects in controlling the trait under study, allowing response to selection processes

Orientador: Elizabeth Orika Ono / Banca: Regina Marta Evangelista / Banca: José Maria Monteiro Sigrist / Resumo: O presente trabalho teve por objetivo avaliar o efeito de reguladores vegetais nas trocas gasosa durante o desenvolvimento da planta e na qualidade pós-colheita de frutos de melão rendilhado Galileu, armazenados em condições ambiente. A primeira etapa do experimento foi conduzida em estufa para cultivo protegido das plantas de melão, localizada na área experimental da Fazenda Experimental de São Manuel/UNESP, Botucatu, SP. A aplicação dos tratamentos foram realizadas no início da fase reprodutiva, 15 e 30 dias após a primeira aplicação. As medidas de trocas gasosas foram realizadas sempre no período das 8:00 às 11:00 horas da manhã, nas plantas controle e tratadas com os reguladores vegetais, no dia anterior e posterior à aplicação. Ci, A, gs e E foram feitas com um Infra Red Gas Analyser IRGA, modelo LI-6400 da LI-COR. As plantas receberam os tratamentos no campo (T1 controle, T2 GA3 (ácido giberélico) a 100 mg L-1, T3 IBA (ácido indolilbutírico) a 100 mg L-1, T4 cinetina a 100 mg L-1, T5 mistura de GA3 + IBA + cinetina a 5%), os frutos foram colhidos (51 dias após a primeira aplicação) e transportados ao Laboratório de Frutas e Hortaliças, pertencente ao Departamento de Gestão e Tecnologia Agroindustrial/UNESP, Botucatu, SP. Os frutos foram avaliados a cada 5 dias, durante 20 dias de armazenamento. As alterações pós-colheita foram detectadas por meio de análises de perda de massa fresca, firmeza, acidez titulável, pH, sólidos solúveis, relação SS/AT, açúcares totais, redutores e sacarose, atividade das enzimas peroxidase (POD), pectinametilesterase (PME) e poligalacturonase (PG). Os macronutrientes e micronutrientes foram analisados na colheita. O delineamento estatístico utilizado foi em blocos ao acaso com o controle e mais quatro tratamentos e quatro repetições que correspondem aos blocos. Nas condições em que o experimento... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: This work's objective was to evaluate the effects of plant growth regulators on gas exchange during plant development and on post harvest quality of Galileu cantaloupes stored at conditions atmosphere. The first stage of the assay was conducted in a greenhouse (protected cultivation of cantaloupe plants), in the experimental area of São Manuel's Experimental Farm/UNESP, Botucatu, SP. The treatments were applied in the beginning of the reproductive stage, and 15 and 30 days after the first application. Gas exchange measurements were performed from 0800 to 1100 a.m, both in control plants and plants treated with plant growth regulators, on the previous and subsequent day from application. Ci, A, gs, and E were evaluated with a LI-COR model LI-6400 "Infra Red Gas Analyzer - IRGA". The cantaloupe plants were treated in the field (T1 controls, T2 GA3 (gibberellic acid) 100 mg L-1, T3 IBA (indolebutyric acid) 100 mg L-1, T4- kinetin 100 mg L-1, T5- GA3 + IBA + kinetin mixture at 5%), and fruits were harvest (51 days after the first application) and transported to the Fruits and Vegetables Laboratory of Departamento de Gestão e Tecnologia Agroindustrial/UNESP, Botucatu, SP. The fruits were evaluated every 5 days during a 20-day storage period. Alterations in post harvest quality were detected through analyses comprising fresh weight loss, firmness, titratable acidity, pH, soluble solids, SS/TA ratio, total sugars, reduced sugars and sucrose, and activity of the enzymes peroxidase (POD), pectin methylesterase (PME), and polygalacturonase (PG). Macronutrients and micronutrients were analyzed at harvest time. The statistical design consisted of randomized blocks including a control, in addition to four treatments and four replicates that corresponded to blocks. Under the conditions in which the experiment was conducted, the results allow us to... (Complete abstract click electronic access below) / Mestre

Orientador: Leila Trevisan Braz / Banca: Letícia Akemi Ito Pontes / Banca: Dilermando Perecin / Banca: Rita de Cássia Panizzi / Banca: Renata Castoldi / Resumo: O uso de resistência genética é considerado uma das melhores estratégias de manejo do oídio das cucurbitáceas (Podosphaera xanthii). Nesse sentido, a identificação de genótipos resistentes faz-se necessária a fim de fornecer aos programas de melhoramento novas fontes de variabilidade. Entretanto, ocorrência de raças do patógeno e a falta de padronização nos métodos de identificação têm dificultado a identificação acurada de raças do patógeno, como também a utilização de resistência genética contra o oídio das cucurbitáceas. A falta de métodos adequados tem dificultado a avaliação de incidência de oídio de modo quantitativo. O método Tripleto-Septeto visa à internacionalização da identificação de raças de oídio pelo uso de 21 linhagens diferenciadoras. O método "Area Under Disease Progress Stairs" (AUDPS) é um método essencialmente derivado do "Area Under Disease Progress Curve" (AUDPC), e ambos têm sido utilizados na avaliação de progressos de doença em outras espécies, ajudando na identificação de genes de efeito menor para resistência. O presente trabalho teve por objetivo identificar uma raça de P. xanthii em casa de vegetação, na UNESP-FCAV, bem como a reação de genótipos de meloeiro a essa raça, e identificar uma raça de oídio das cucurbitáceas em casa de vegetação, por meio do método Tripleto-Septeto, e estimar o progresso do oídio das cucurbitáceas em 21 linhagens diferenciadoras, via AUDPC e AUDPS. No primeiro experimento, foram avaliados 61 acessos de melão, duas cul... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: Genetic resistance is considered one of the most suitable strategies to control cucurbit powdery mildew (CPM) incited by (Podosphaera xanthii). Accordantly, the identification of resistant genotypes is necessary to provide to breeding programs new sources of variability. However, the occurrence of races, and the lack of standardization of methods of identification have been hampered the use of genetic resistance against cucurbit powdery mildew. The lack of suitable methods has made difficult the assessment of CPM in quantitative ways. The method Triplet-Septet aims the internationalization of CPM identifications by using a set of 21 differentials. The method Area Under Disease Progress Stairs (AUDPS) is essentially derived from Area Under Disease Progress Curve (AUDPC), and both have been used to evaluate disease progresses on other crops, helping to identify minor genes for resistance. This thesis aimed to identify a P. xanthii race in a greenhouse at the UNESP-FCAV, as well the reaction of melon genotypes to that race; to identify a new cucurbit race in greenhouse via Triplet-Septet method; and to estimate the CPM disease progress on 21 race differentials, via AUDPC and AUDPS. The first experiment evaluated 61 melon germplasm accessions, two net melon cultivars ('Louis' and 'Fantasy'), six net melon elite-inbred lines, and the winter melon (Benincasa hispida) regarding their reactions to a CPM population, naturally occurring in a greenhouse, in Jaboticabal, SP. Seven of the 61 germplasm accessions are known as CPM race differentials: PI 414723, 'PMR 45', 'PMR 5', 'WMR 29', 'Edisto 47', 'Nantais Oblong' and 'Védrantais'. The third true leaf of each plant was inoculated with fragments of mycelia at seven-days after transplanting and evaluated 42-days after inoculation, based on visual scale. The second experiment, about (Complete abstract click electronic access below) / Doutor

Orientador: Leila Trevisan Braz / Coorientador: Margarete Camargo / Banca: Rita de Cássia Panizzi / Banca: Pablo Forlan Vargas / Banca: José Branco de Miranda Filho / Banca: Dilermando Perecin / Resumo: Dentre as doenças que acometem a cultura do meloeiro, o cancro-da-haste, causado por Didymella bryoniae, atualmente é considerada a principal doença para a cultura, provocando perdas econômicas substanciais. Nesse contexto, o uso de cultivares resistentes, aparece como medida ideal e estratégica no manejo integrado dessa doença. Para se obterem cultivares resistentes, é preciso identificar as melhores fontes de resistência, ter um método de avaliação da resistência eficiente, rápido e prático, e conhecer a herança genética dessa característica. Para tanto, o trabalho teve os seguintes objetivos: a) avaliar a reação de acessos de meloeiro a D. bryoniae; b) testar métodos e tempos (dias após a inoculação) para a avaliação da reação de genótipos de meloeiro ao referido patógeno e c) determinar os valores das capacidades geral (CGC) e específica de combinação (CEC) de seis genótipos de meloeiro, a fim de avaliar o potencial desses como genitores para uso em programas de melhoramento, visando obtenção de linhagens com resistência a D. bryoniae. O trabalho dividiu-se, portanto, em três etapas, sendo a primeira o estudo da reação dos genótipos, a segunda a avaliação de métodos e dias após a inoculação, na severidade do cancro-da-haste nos genótipos e, a terceira estudar o potencial de genitores para uso em programas de melhoramento, visando obtenção de linhagens com resistência a D. bryoniae. Os experimentos foram conduzidos no Setor de Olericultura e Plantas Aromático-Medicinais e ... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: Among the diseases that affect the melon crop, the gummy stem blight, caused by Didymella bryoniae, is currently considered the most important and causal agent of substantial losses. In this context, the use of resistant appears as an advisable strategy in the integrated management of the disease. In the process to obtain resistant cultivars, it is necessary primarily to identify reliable sources of resistance and use an appropriate method to effectively evaluate the plant-pathogen interaction; the methodology must be fast, convenient and compatible with the genetic inheritance of this characteristic. Under this viewpoint, the present work had the following objectives: a) evaluation of melon accesses for resistance to D. bryoniae. b) adjustment of methodology, including the appropriate time (days after inoculation) to the evaluate the reaction of melon genotypes to the pathogen; c) estimation of the effects of general combining ability (GCA) and specific combining ability (CEC) in a diallel cross among six lines of muskmelon to provide basic information for their use as parents in breeding programs toward the development of line with resistance to D. bryoniae. The experiments were conducted in the Setor de Olericultura e Plantas Aromático-Medicinais e no Laboratório do Departamento de Fitossanidade, na Faculdade de Ciências Agrárias (UNESP-FCAV) - Câmpus de Jaboticabal. The results regarding the reaction to gummy stem blight identified the access AC-29, C160, Charentais Fom 1... (Complete abstract click electronic access below) / Doutor

Orientador: Miriam Dupas Hubinger / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia de Alimentos / Made available in DSpace on 2018-08-04T02:50:30Z (GMT). No. of bitstreams: 1 Ferrari_CristhianeCaroline_M.pdf: 1666755 bytes, checksum: fa3100a4126563ef9d7341d049583dba (MD5) Previous issue date: 2005 / Resumo: O presente trabalho teve como objetivo estudar a cinética de desidratação osmótica de pedaços de melão em soluções de sacarose e maltose, avaliando-se parâmetros de textura e cor ao longo do processo. Cubos de melão da variedade Cucumis melo inodorus, cultivar Gold Mine, de 20 mm foram imersos em soluções hipertônicas de sacarose ou maltose nas concentrações de 40 a 60°Brix e o processo foi conduzido por 8 horas com temperatura controlada (30 ou 40°C) e agitação de 120 rpm. Perda de água e de peso, incorporação de sólidos na fruta, atividade de água, cor e textura foram analisadas ao longo do processo em função da temperatura de tratamento, tipo e concentração da solução. O ponto final de equilíbrio e os coeficientes de difusão para a água e os açúcares foram estimados através de um modelo empírico da literatura, baseado na equação de Fick, comparando-se os efeitos da sacarose e da maltose na transferência de massa durante o processo. Para todos os ensaios, a perda de água e de peso aumentaram significativamente com a elevação da temperatura e da concentração da solução desidratante, entretanto os ensaios com maltose promoveram uma maior taxa de saída de água da fruta e menor ganho de sólidos. As características de cor da fruta fresca permaneceram praticamente inalteradas pela desidratação osmótica, observando-se apenas uma intensificação da cor ocasionada pelo aumento dos valores do parâmetro b* e do croma C*, devido à concentração de pigmentos provocada pela perda de água ao longo do tempo. Em relação à textura, houve um aumento na natureza viscosa e perda de elasticidade durante o processo, por conseqüência da incorporação de sólidos, que causa uma plasticidade na estrutura, porém a maltose se mostrou mais efetiva na manutenção das características de textura da fruta fresca. Foram selecionadas as condições mais favoráveis para cada uma das respostas estudadas, com o intuito de se realizar uma análise sensorial, sendo que, especificamente para estes ensaios, o tempo de tratamento foi de duas horas, determinado a partir das cinéticas de perda de água, ganho de sólidos e textura. Os resultados da avaliação sensorial revelaram que a desidratação osmótica forneceu um produto com boa aceitação pelo consumidor. / Abstract: The objective of this work was to study the osmotic dehydration kinetics of melon pieces in two types of solution (sucrose and maltose), with simultaneous evaluation of texture and color parameters all along the process. Melon (Cucumis melo inodorus, cultivar Gold Mine) cubes of 20 mm were immersed in hypertonic solution of sucrose or maltose with different concentrations (40 to 60°Brix) and the process was carried out for eight hours under controlled temperature (30°C or 40°C) and agitation (120 rpm). Water and weight loss, solids gain, water activity, color and texture were analysed throughout the process as a function of temperature, osmotic agent and solution concentration. The final equilibrium point and the diffusion coefficients for water and sugar were estimated using an empiric model from literature based on Fick's unsteady law of diffusion in order to compare sucrose and maltose effects in mass transfer rates during the osmotic process. For all treatments, water removal and weight loss increased at a significant level for higher temperature and solution concentrations, but the greatest water loss rate and lowest sugar uptake was verified when using maltose solutions. The color fresh-like characteristics were practically kept by the osmotic dehydration, with a slightly color intensification due to an increase on the b* parameter and on chrome values, as a consequence of fruit pigments concentration, caused by water loss. For the texture, an increase of viscous nature of fruit and elasticity loss was observed, indicating that the sugar impregnation occurred along the process provoked a plasticity in fruit structure. Maltose showed to be more effective on fruit texture maintenance. The best conditions for each one of the response variables were selected and the final product was evaluated by a sensorial analysis. The treatment time for these tests was two hours, determined by water loss, solids gain and texture kinetics. Sensorial results revealed that osmotic dehydration provided a good product acceptance by the consumer / Mestrado / Engenharia de Alimentos / Mestre em Engenharia de Alimentos

Thesis (PhD(Agric))--University of Stellenbosch, 2000. / ENGLISH ABSTRACT: The purpose of this study was to characterize the race and vegetative compatibility of Fusarium oxysporum f. sp. melonis (FOM) isolates collected in the major melon producing areas, to report on their geographical distribution, and their possible relatedness to isolates from other countries. Seventy two FOM isolates obtained from 30 fields in 17 melon producing regions were race-typed using the differential cultivars Topmark (susceptible to all races), Doublon (Fomi), CM 17187 (Fom2) and Perlita (Fom3) and grouped by means of vegetative compatibility. All isolates belonged to vegetative compatibility group 0134, indicating a high degree of genetic homogeneity among the South African FOM population. Fifty four isolates were identified as race 0, eight as race 1, and 10 as race 2. Race 0 occurred in 15 of the regions whereas race 1 was sporadically recovered. Race 2, on the other hand, was obtained only from four fields located in one geographical region. Perlita plants (carrying the gene Fom3) inoculated with local isolates ofrace 0 and race 2 and reference isolates of race 0 became stunted, their leaves turned yellow, and became thickened and brittle. These results suggested that Fom3 in Perlita confers a tolerant reaction compared to the resistant reaction of gene FornI in Doublon. The disease reaction of cultivar Perlita to FOM was therefore reinvestigated. Twenty isolates, including the four FOM races (0, 1, 2, and 1,2) obtained from different countries, were used. The differential cultivars were included to verify virulence of the isolates. Perlita plants inoculated with three isolates of race 2 remained asymptomatic. The remaining race 2 and 0 isolates, induced severe stunting of Perlita plants, but mean percentage stunting values did not differ significantly (P = 0.05) and ranged between 25.1 and 50.0. Leaves of stunted plants were chlorotic, thickened and brittle. Disease reaction of Perlita was verified at a lower inoculum concentration with two race 2 (pipette method) and two race 0 isolates (root dip method). Results proved that Fom3 does not confer similar resistance towards race 0 and some race 2 isolates as FornI in Doublon. Cultivars possessing Fom3, should therefore be considered tolerant to FOM races 0 and 2. The ability of a nit mutant isolate, generated from FOM race 0 which belongs to VCG 0134, to change its virulence during infection of melon plants, was investigated under quarantine. Seedlings of melon cultivars Imperial 45 and Early Sweet (no resistance genes), Amber (Fom2) and Fiata (FomI, Fom2) were consecutively grown in two cement troughs in a gauzehouse. Each planting was terminated when plants had advanced Fusarium wilt or after the fruit were harvested. In the first planting, Imperial 45 seedlings were transplanted and artificially inoculated with the nil mutant isolate. In the consecutive plantings, seeds were sown in the infested soil to enable natural infection. For each crop, representative plants showing Fusarium wilt were selected for isolation. All F. oxysporum isolates recovered were single-spored and their nit mutant and VCG status verified. Virulence of the labelled isolates was determined using differential cultivars. In trough A, all plants of the susceptible cultivars Imperial 45 and Early Sweet crops showed Fusarium wilt. The labelled isolates recovered from the selected plants were all designated race O. In the first crop (planting No.5) of the resistant cultivar Amber, 6.7% of the plants developed Fusarium wilt. In the second Amber crop the disease incidence increased to 56.6%, and to 81.8% in the final crop. Contrary to the susceptible cultivars, only race 2 isolates were obtained from the symptomatic Amber plants. Similar data were found with the susceptible cultivar Imperial 45 and the resistant cultivar Amber in trough B. Planting of Fiata caused a dramatic reduction in Fusarium wilt incidence in trough B. However, 1.2% of plants were affected by Fusarium wilt in the first Fiata crop (planting No.6), whereas 4% of the plants were symptomatic in the final planting. From these symptomatic Fiata plants only race 1,2 isolates were obtained. These findings, and the fact that the symptomatic plants represented a substantial proportion of the first Amber (approximately 7-15%) and Fiata (approximately 2%) crops, provedthat changes in the race structure of this fungal pathogen occurred rapidly when confronted with a resistant cultivar. The potential of RAPD analysis to differentiate between the isolates displaying virulence changes was evaluated. Four F. oxysporum f. sp. niveum isolates were included as an outgroup. A histopathological study was conducted to verify whether these isolates retain their ability to behave as true vascular pathogens. The three primers used clearly distinguished the 12 FOM isolates from the four F. oxysporum f. sp. niveum isolates. However, the primers showed a highly conserved and characteristic banding pattern for the FOM isolates which represented three physiological races (race 0, race 2, race 1,2), indicating that RAPD analysis cannot detect race-specific groupings in FOM. Disease reactions on the three differential cultivars confirmed the virulence of FOM isolates. The histopathological data furthermore proved that the two FOM races (race 2, race 1,2), which derived from the race 0 parent isolate, retained their ability to behave as true vascular pathogens. / AFRIKAANSE OPSOMMING: DIE KARAKTERISERING EN PATOGENESITEIT VAN SUID-AFRIKAANSE ISOLATE VAN FUSARIUMOXYSPORUMF. SP.MELONIS Die doel van die studie was om Fusarium oxysporum f. sp. melonis (FOM) isolate wat in die hoof spanspekproduserende gebiede versamel is, volgens ras en vegetatiewe verenigbaarheid te karakteriseer, en hul geografiese verspreiding en verwantskap met isolate van ander lande aan te dui. Twee en sewentig FOM isolate afkomstig vanaf 30 landerye wat 17 spanspekproduserende areas verteenwoordig, is gebruik. Die differensiële kultivars Topmark (vatbaar vir alle rasse), Doublon (Forni), CM 17187 (Fom2) en Perlita (Fond) is gebruik om die rasbepalings te doen asook om die vegetatiewe verenigbare groepe (VVG) te bepaal. Al die isolate is as VVG 0134 geklassifiseer, wat 'n hoë mate van genetiese homogenesiteit binne die Suid-Afrikaanse populasie aandui. Vier en vyftig isolate is as ras 0, agt as ras 1 en 10 as ras 2 geklassifiseer. Ras 0 is vanaf 15 gebiede afkomstig, terwyl ras 1 sporadies voorgekom het. Ras 2 is vanuit vier landerye binne dieselfde geografiese gebied verkry. Plante van die kultivar Perlita wat met plaaslike isolate van ras 0 en 2, asook verwysings-isolate van ras 0 geïnokuleer is, het verdwerg voorgekom. Die blare van die plante het vergeel, verdik en bros voorgekom. Hierdie siekte reaksie het aangedui dat Fond in Perlita toleransie bewerkstellig in teenstelling met die weerstandbiedende reaksie van geen Fomi in Doublon. Die siekte reaksie van Perlita teenoor FOM is dus verder ondesoek. Hiervoor is 20 isolate wat al vier FOM rasse insluit (0, 1, 2, en 1,2), en van verskillende wêrelddele afkomstig is, gebruik. Die virulensie van die isolate is met die differensiële kultivars bevestig. Drie van die ras 2 isolate het geen siektesimptome op Perlita veroorsaak nie. Die ander ras 2 isolate, en al die ras 0 isolate, het egter die Perlita plante aansienlik verdwerg en die blare vergeel en verdik. Laasgenoemde groep isolate het 'n gemiddelde verdwergingsindeks van tussen 25.1% en 50.0% veroorsaak. Die siekte reaksie by Perlita is verder bevestig deur plante teen 'n laer inokulumdigtheid van twee ras 2 (pipet metode), en twee ras 0 (wortel-doop metode) isolate, te inokuleer. Uit die resultate was dit duidelik dat die weerstand wat Fom3 teenoor ras 0 en sommige ras 2 isolate verskaf, van FornI verskil. Kultivars wat oor die weerstandsgeen Fom3 beskik moet dus as tolerant beskou word. 'n Ondersoek is geloods na die vermoë van 'n nil mutant isolaat, genereer vanaf die wilde ras 0 isolaat van FOM (VVG 0134), om onder kwarantyn sy virulensie gedurende infeksie van spanspekplante te verander. Saailinge van die spanspekkultivars Early Sweet (geen weerstandsgene), Amber (Fom2) en Fiata (FornI, Fom2) is opeenvolgens in twee sement trêe in 'n gaashuis verbou. Die afsonderlike aanplantings is beëindig sodra gevorderde Fusarium-verwelksimptome verkry is, of nadat vrugte ge-oes is. Vir die eerste aanplanting is oorgeplante Imperial 45 saailinge kunsmatig met die nil mutant isolaat geïnokuleer. Tydens die opeenvolgende aanplantings is saad direk in die besmette grond gesaai ten einde natuurlike infeksie te verkry. Met elke aanplanting is isolasies gedoen vanaf verteenwoordigende plante wat Fusarium-verwelksimptome getoon het. Alle F. oxysporum isolate wat verkry is, is ge-enkelspoor en hul nit mutant status en VVG is bevestig. Virulensie van die gemerkte isolate is bepaal deur inokulasie van die differensiële kultivars. Alle plante van die vatbare Imperial 45 en Early Sweet kultivars wat in trog A geplant is, het Fusarium-verwelksimptome getoon. Die gemerkte isolate wat vanaf die verteenwoordigende plante verkry is, is almal as ras 0 geklassifiseer. Tydens die eerste aanplanting van die weerstandbiedende kultivar, Amber (aanplanting No.5), het 6.7% van die plante Fusarium-verwe1ksimptome ontwikkel. Tydens die tweede en derde aanplanting van Amber het die frekwensie van siektevoorkoms verhoog na 56.6% en 81.8 %, onderskeidelik. In teenstelling met die vatbare kultivars, is slegs ras 2 vanuit die Amber plante met siektesimptome verkry. Soortgelyke resultate is met Imperial 45 en Amber in trog B verkry. Aanplanting van kultivar Fiata het egter 'n dramatiese verlaging in die voorkoms van Fusarium-verwelk bewerkstellig. Tydens die eerste Fiata aanplanting (aanplanting No.6) het 1.2% plante Fusarium-verwelksimptome ontwikkel, en 4% tydens die laaste aanplanting. Vanaf hierdie plante is slegs ras 1,2 isolate verkry. Hierdie bevindings, en die feit dat 'n aansienlike hoeveelheid van die Amber (ongeveer 7-15%) en Fiata plante (ongeveer 2%) siektesimptome getoon het, bewys dat FOM vinnig van virulensie verander wanneer die patogeen 'n weerstanbiedende kultivar infekteer. Die vermoë van RAPD analise om tussen isolate wat in virulensie verander het, te onderskei, is ondersoek. Vier isolate van F. oxysporum f. sp. niveum is as 'n buite-groep ingesluit. Om te bevestig dat die isolate wat van ras verander het wel egte vaskulêre patogene is, is 'n histopatologiese ondersoek gedoen. Die drie inleiers wat gebruik is, het die 12 FOM isolate duidelik van die vier F. oxysporum f. sp. niveum isolate onderskei. Die 12 FOM isolate wat drie fiosologiese rasse (ras 0, ras 2, ras 1,2) verteenwoordig het, is egter saam gegroepeer, wat aandui dat hierdie metode nie tussen rasse van FOM kan onderskei nie. Inokulasiestudies met die differensiële kultivars het die virulensie van die isolate bevestig. Die histopatologiese ondersoek het verder bewys dat beide FOM rasse (ras 2, ras 1,2) wat vanaf die wilde tipe ras ° isolaat ontstaan het, hul vermoë behou het om as egte vaskulêre patogene op te tree.

Resumo: A produção de melão vem se tornando cada vez mais tecnificada, principalmente para a região semi-árida nordestina. Este interesse de tentar cada vez mais melhorar as condições de manejo da cultura faz com que os produtores tenham a cada dia, uma produção de qualidade. Existem alguns fatores que podem interferir nestas buscas de aperfeiçoamento das técnicas de manejo, como, por exemplo, as exigências do manejo hídrico na cultura. Por outro lado, a maior demanda por água tem levado a uma diminuição da maioria das fontes de água de boa qualidade disponíveis na região, obrigando a utilização de água com diferentes níveis de salinidade. Partindo-se desses fatores, o presente trabalho teve como objetivo estudar os efeitos de diferentes níveis de salinidade da água, freqüência e lâminas de irrigação em alguns cultivares de melão, ora destacando-se como promissoras para o mercado consumidor nacional e internacional, como também avaliar o processo de salinização do solo. Para isso, conduziram-se dois experimentos consecutivos em campo, numa mesma área, medindo 0,19 ha. No primeiro estudou-se o efeito de três níveis salinos (CE de 1,1; 2,6 e 3,9 dS.m-1), duas lâminas de irrigação (1,1ETm e 1,25ETm) e duas freqüências de irrigação (diária e 2 dias) utilizando a cultivar de melão amarelo Gold mine. No segundo experimento utilizaram-se três níveis salinos (CE de 1,1; 2,5 e 4,5 dS.m-1), duas freqüências de irrigação (diária e 2 dias) e duas cultivares de melão cantaloupe (Trusty e Orange Flesh). O experimento foi composto de quatro blocos ao acaso, cada um dividido em doze parcelas tratamento medindo 6 m x 6 m, irrigadas por gotejamento. O resultado do primeiro experimento apresentou que o processo de salinização do solo ocorreu durante o ciclo da cultura, diminuindo significativamente no período das chuvas que correspondeu... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: The melon production, particularily in the semi-arid region of Northeast of Brazil, is becoming highly technological. The interest to improve crop management conditions is to provide melon produces opportunity to obtain better quality production. The are, however, some factors which may interfer in further improvement of management techniques, for exemple needs of water management of the crop. On the other hand, the increased demand of water has decreased availability of good quality water sources in the region, thereby, oblising use of water of different salinities. Keeping this in view, the present study had the objective of verifying the effects of water of different salinities, frequency and irrigation depths in some promising melon cultivars for the national and international consumer market, as well as to evaluate process of salinization. For this, two consecutive field experiments were conducted in a same area of 0,19 ha. In the first trial the effets of three salinity levels (electrical conductivity - ECw of 1.1, 2.6 and 3.9 dS.m-1), two irrigation depths (1.1Etm and 1.25ETm) and two frequency of irrigation (daily and every two days) were studied utilizing Yellow Gold Mine melon cultivar. In the second experiment the salinity levels (Ecw of 1.1, 2.5 and 4.5 dS.m-1), two frequency of irrigation (daily and at interval of two days) and two cultivars (Trusty and Orange Flesh) of cantaloup melon were studied. The experiment consisted of four randomized blocks, each one divided into 12 drip irrigated treatment plots of 6 x 6 m. The result of first experiment revealed that the soil salinization occurred during the crop cycle but decreased appreciably during the rainy period which corresponded to interval between two crop cycles. The regression equations which correlated the EC1:2 and ECse in 0-30 cm depth foun were... (Complete abstract click electronic access below) / Orientador: Antônio de Pádua Sousa / Coorientador: José Francismar de Medeiros / Banca: João Carlos Cury Saad / Banca: Raimundo Leite Cruz / Banca: José Renato Zanini / Banca: Tarlei Arriel Botrel / Doutor

Thesis (M. Sc. (Botany)) -- University of Limpopo, 2015 / The aim of this study was to investigate the chemical composition of indigenous watermelon landraces (Citrullus lanatus) seeds grown in two districts in the Limpopo Province. Watermelon seeds are the most undermined oilseeds. The seeds have nutritional values that compare favourably with those of soybean, sunflower and ground nuts. Many cucurbit seeds such as watermelon seeds are rich in protein and oil, although none of these products have been used on an industrial scale. Nine indigenous watermelon landraces seeds (four from the Sekhukhune district and five from the Capricorn district) were examined. The landrace 06CDGM was found to have the highest mass per one hundred seeds (10.95 g per 100 seeds) with 07CDGM having the lowest mass (8.05 g per 100 seeds). The landrace 10CDGM was found to have the highest oil (41.5%), protein (20.39%) and fibre content (23.98%) with 01SDPW having the lowest oil yield (30.00%), 02SDPW was found to have the highest saponification value (184.57 mg KOH/g oil) and 09CDGM had the highest iodine value (138.575 g I2/100 g oil). The landrace 01SDPW had the highest total sugar content. All landraces were found to have the essential amino acid leucine. Antioxidant activity (66.95%) and total flavonoids (0.295 mg/g as catechin equivalents) were found to be highest in the 09CDGM landrace, and total phenolic content (0.91 mg/g gallic acid equivalent) was found to be highest in 05SDPW. The landrace 06CDGM was found to have the highest copper content (0.088 mg/g); 02SDPW was found to have the highest iron content (0.194 mg/g); 10CDGM had the highest zinc (0.312 mg/g) and sulphate content (0.129 mg/g); while both 10CDGM and 03SDPW had the highest content of calcium (9.13 mg/g). The landraces were found to differ slightly in the content and quality of components tested. Each of the landraces was found to have some qualities that render them superior to the other landraces. The qualities and content of the landraces compare favourably with those of commercial oil seeds such as the sunflower and soybean. Overall, the landraces from the Capricorn district were observed to have superior qualities than those from the Sekhukhune district. The findings indicated that the landraces from Capricorn district had more mean oil, mean protein, crude fibre content, total phenolics and total flavonoid content than those from the Sekhukhune district. The landraces from Sekhukhune district had high carbohydrate, ash content and high content of the minerals iron and calcium. The landrace 10CDGM was found to have overall high vi values with regard to most analyses, thus making the landrace superior to the others. The results indicate that landraces from both districts have complementary qualities to each other; however the landraces from the Capricorn are more superior in most aspects. The watermelon seeds have the potential to be used as a cost-effective and easily accessible source of nutrients and oil to meet nutritional challenges in developing countries. KEY CONCEPTS Citrullus lanatus; Landrace; Sekhukhune district; Capricorn district; Indigenous watermelon; Oil seeds; Essential amino acids; Antioxidant activity; Total phenolics; Total flavonoids; Mineral content; Total sugars; Crude fibre; Oil content; Saponification value; Iodine value.

The challenge of food security requires that agricultural production is no longer based on a narrow genetic material present in conventional crops. Whereas conventional crops have been genetically improved to suit management practices of the modern farmer, the future farmer requires that there be access to a wide variety of genetic material for economic exploitation and to respond to the challenges of climate change in a sustainable fashion. This study was designed to learn about production of wild water melon [Citrullus lanatus (Thunb.) Matsumura and Nakai] from seed germination, seedling establishment and field crop production. The specific objectives of the study were (a) to determine the effect of water stress on three landraces of watermelon differing in seed colour and provenance during seedling establishment, (b) to determine the effect of planting date on crop growth and yield under field conditions, and (c) to relate proline accumulation to water stress in wild watermelon. Three seedlots, ‘B’, ‘DB’ and ‘VDB” were derived from seeds collected from subsistence farming communities of the Eastern Cape, and KwaZulu-Natal. Following one season of seed production in Pietermaritzburg, KwaZulu-Natal, seeds were tested for germination capacity, before seedlot response to water stress was determined in three substrates made of pine bark, a 1:1 mixture of fine sand and pine bark and fine sand only. The substrates were kept at 75% FC, 50% F.C and 25% F.C., to create varying levels of water regimes during 12 weeks of seedling growth in a glasshouse (16/21oC (day/night) and 60% RH). Leaf proline content was determined at seedling harvest. Crop production under field conditions occurred at one site with three planting dates late September 2008, November 2008 and January 2009, respectively. There were significant differences among seedlots with respect to seed quality and seedling yield, which consistently showed that B > VDB > DB. The differences in seedlots continued in the same order even in response to field conditions. Wild watermelon was responsive to water stress during seedling growth, but high water regimes compromised water use efficiency. Proline accumulation correlated with water stress. The best plant growth and yield under field conditions was obtained when planting occurred in September, followed by November and January plantings, respectively. Early planting was also associated with high crop growth rate and larger fruit size. It is concluded that despite being a desert crop, wild watermelon responds to water deficits during seedling growth. Results of field studies cannot be conclusively used to determine crop response to water stress, although they gave a good indication of crop response to different conditions of rainfall and temperature at the study site from September to March. / Thesis (M.Sc.Agric.)-University of KwaZulu-Natal, Pietermaritzburg, 2010.

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