Thesis (M.S.)--University of Wisconsin--Madison, 1968. / eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references.

Hamburg, Universiẗat, Diss., 2003.

Techn. Universiẗat, Diss., 2001--Berlin.

Thesis (Ph. D.)--University of Wisconsin--Madison, 1948. / Typescript. Vita. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references (leaves 55-58).

Fusarium head blight (FHB) is a horribly destructive fungal diseases of barley. FHB is caused by a species complex of Fusaria, of which Fusarium graminearum Schwabe is the main causal species of FHB epidemics in Canada. Field surveys show that two or more Fusarium species often co-exist within the same field or grain sample and F. poae is reported as another important species in barley in Ontario and Quebec. The aim of this study was to observe the pathogenicity of F. graminearum, F. poae and a co-inoculation of both species causing FHB in barley. Two susceptible barley cultivars were spray-inoculated at 10 to 14 days after heading. Phenotypic disease severity was rated on a scale of 0-9 at 4, 7, 14, 21, and 28 days after inoculation. There was a significant difference in FHB severity between F. graminearum and F. poae, where infection with F. graminearum produced more severe disease ratings. F. poae generated lower disease ratings and was not statistically different from the control. When heads were co-inoculated with both Fusarium species, the resulting FHB severity was unchanged 54relative to heads inoculated with F. graminearum only. The ratio of F. graminearum to F. poae genomic DNA was also no different than when heads were inoculated with F. graminearum alone, as quantified with ddPCR using markers specific to each species. Metabolomic analysis of sample extracts corroborated our other findings where F. graminearum appeared to outcompete F. poae in barley also at the mycotoxin level. Barley cultivar did not have a significant effect on visual FHB disease ratings and fungal DNA detection, however there were some chemical differences between cultivars in response to challenge by both F. graminearum and F. poae.

Thesis (MSc)--Stellenbosch University, 2015 / ENGLISH ABSTRACT: Maize (Zea mays L.) is an important crop worldwide and forms the staple diet of many African countries including South Africa. Fusarium ear rot (FER) of maize is caused by a fungus, Fusarium verticillioides, which also produces the fumonisin mycotoxin group. The consumption of fumonisin contaminated maize grain has been associated with serious human and animal health complications. Several South African maize inbred lines exhibiting resistance to FER and fumonisin contamination have been identified. These locally adapted inbred lines could be used to generate mapping populations to identify QTLs associated with resistance to FER and fumonisin contamination. The corresponding markers could be utilised in breeding programmes through marker-assisted selection to ensure the development of commercial cultivars with resistance to FER and fumonisin contamination. In this study, resistant and susceptible maize inbred lines were utilised to commence the development of recombinant inbred line (RIL) populations for the mapping and validation of QTLs associated with FER and fumonisin resistance. One F2 population was phenotypically and genotypically analysed to produce a linkage map for the preliminary identification of QTLs associated with resistance to F. verticillioides infection and fumonisin deposition. A potential QTL for resistance to FER was detected and should be validated across several locations and years in the subsequent RIL population. Additionally, potential resistance barriers of maize to infection by F. verticillioides were investigated by histological studies. The importance of a closed stylar canal in determining resistance to FER was established for nine South African maize inbred lines by means of scanning electron microscopy (SEM). No significant association was observed between a closed stylar canal and the resistance/susceptible status of maize inbred lines before pollination, while the canals appeared closed in all inbred lines following pollination. The results suggest that the stylar canal architecture is not an essential factor determining resistance to F. verticillioides ingress in the maize inbred lines selected for this study. Furthermore, the possibility of resistance to FER and fumonisin contamination being initiated during the seedlings phase of a resistant and susceptible maize inbred line was investigated by means of confocal laser scanning microscopy (CLSM). Fusarium verticillioides growth originating from soil-borne or seed-borne contamination was monitored in various above and below soil plant tissues but no significant difference in the colonisation could be determined between resistant and susceptible maize seedlings. No fumonisin was produced regardless of the inoculation method or resistance status of the plant. These results suggests that the resistant and susceptible maize seedlings used in this study may not be resistant to systemic fungal ingress but may resist the deposition of fumonisins. The resistance associated with the resistant inbred line is not mediated during the seedling phase but potentially through structural and biochemical defence mechanisms during later plant developmental stages. / AFRIKAANSE OPSOMMING: Mielies (Zea mays L.) is ‘n belangrike graangewas wat wêreldwyd geproduseer word en dien as stapelvoedsel in talle Afrika-lande, insluitend Suid-Afrika. Fusarium kopvrot (FKV) in mielies word veroorsaak deur die swam, Fusarium verticillioides, wat ook die fumonisien mikotoksien groepe produseer. Die inname van fumonisien-geïnfekteerde mielies gaan gepaard met ernstige gesondheidsprobleme in mense en diere. Verskeie Suid-Afrikaanse ingeteelde mielielyne, wat weerstandbiedend is teen FKV en fumonisien kontaminasie, is voorheen identifiseer. Hierdie plaaslik-aangepaste teellyne kan gebruik word om kartering populasies te genereer om kwantitatiewe eienskap loci (KEL) te identifiseer wat verband hou met weerstandbiedenheid teen FKV en fumonisien kontaminasie. Die ooreenstemmende merkers kan gebruik word in teelprogramme deur gebruik te maak van merker-geassisteerde seleksie om kommersieële kultivars, wat weerstandbiedend is teenoor FKV en fumonisien kontaminasie, te ontwikkel. In hierdie studie is weerstandbiedende en vatbare mielie inteellyne gebruik om rekombinante inteellyn (RIL) populasies te begin ontwikkel vir die kartering en validasie van KEL’e geassosieer met FKV en fumonisien weerstandbiedenheid. Een F2 populasie was fenotipies en genotipies geanaliseer om ‘n koppeling-kaart te verwek vir die voorlopige identifikasie van KEL’e geassosieer met weerstandigheid tot F. verticillioides infeksie en fumonisein afsetting. ‘n Potensiële KEL vir weerstandbiedenheid is geïdentifiseer, wat verdere bevestiging in die daaropvolgende RIL populasie in verskeie geografiese areas en oor addisionele seisoene, benodig. Potensiële fisiese versperrings teen F. verticillioides tydens mieliesaad infeksie is ook ondersoek met behulp van histologiese studies. Die belangrikheid van ‘n geslote styl-kanaal vir weerstandbiedendheid teenoor FKV is bevestig in nege Suid-Afrikaanse inteellyne deur middel van skandeer elektron mikroskopie (SEM). Geen beduidende verwandskap tussen ‘n geslote styl-kanaal en die weerstandbiedenheid/vatbaarheid van die inteellyne voor bestuiwing is gevind nie, terwyl die kanaal in alle inteellyne gesluit was na bestuiwing. Die resultate dui daarop dat die styl-kanaal argitektuur nie ‘n noodsaaklike faktor is in die bepaling van weestand tot F. verticillioides besmetting in die suiwer mielielyne wat geselekteer was in hierdie studie nie. Verder is die moontlikheid dat weestand tot FKV en fumonisien kontaminasie geïnisieer kan word gedurende die saailing-fase ondersoek in beide ‘n weerstandbiedende en vatbare mielie inteellyn met behulp van konfokale laser skandering mikroskopie (CLSM). Die groei van F. verticillioides afkomstig vanuit die grond of saad is gemonitor in verskeie bo- en ondergrondse plantweefsels, maar geen beduidende verskille in kolonisasie kon opgespoor word tussen weerstandbiedende en vatbare mielie saailinge nie. Geen fumonisien produksie is waargeneem nie, ongeag die innokulasie metode of weerstand-status van die plant. Hierdie resultate dui daarop dat die weerstandbiedende en vatbare mielie saailinge wat in hierdie studie gebruik is moontlik nie weerstandbiedend is teen sistemiese swaminfeksie nie, maar wel weerstand kan bied tot afsetting van fumonisiene. Die weerstand geassosieër met die weerstandbiedende inteellyn word nie bemiddel gedurende die saailingfase nie maar waarskynlik deur strukturele en biochemiese verdedigingsmeganismes tydens latere plant ontwikkelings-stadia. / National Research Foundation (NRF)

Thesis (Ph. D.)--University of Wisconsin--Madison, 1959. / Typescript. Vita. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references (leaves 126-132).

Thesis (M.Sc.)(Biochemistry)--University of Pretoria, 2006. / Includes summary. Includes bibliographical references. Available on the Internet via the World Wide Web.

Orientador: Raquel Ghini / Coorientador: Edson Luiz Furtado / Banca: Dartanhã José Soares / Banca: Adriana Zanin Kronka / Banca: Adibe Luiz Abdalla / Banca: Miguel Angel Dita Rodrigues / Resumo: A concentração atmosférica de CO2, principal gás responsável pela intensificação do efeito estufa, vem aumentando significativamente nas últimas décadas. A alfafa é uma importante forrageira que pode ter suas características alteradas pelo aumento da concentração de CO2 atmosférico, favorecendo a ocorrência de doenças e intensificando a emissão de gases de efeito estufa após sua ingestão por animais. Diante desse cenário, o objetivo desse trabalho foi verificar o impacto do aumento da concentração de CO2 do ar em doenças da alfafa, crescimento das plantas e composição bromatológica. Os ensaios foram realizados em campo, com semeadura direta de sementes de alfafa da cultivar crioula em estufas de topo aberto (OTC), adotando o delineamento experimental em blocos casualizados, com três repetições. Os tratamentos foram: testemunha sem OTC, com a concentração de 390 μmol mol-1 de CO2; OTC sem injeção de CO2, com 400 μmol mol-1 de CO2; e OTC com injeção de CO2 até atingir 500 μmol mol-1 de CO2. Na parte aérea das plantas, foram realizadas análises para determinar a matéria seca, matéria mineral, matéria orgânica, nitrogênio em fibra detergente neutro (n-FDN), nitrogênio em fibra detergente ácido (n-FDA), proteína bruta e lignina e análise química foliar. Além dessas, foram realizadas medidas da altura das plantas, relação entre o comprimento da haste e da raiz, peso da biomassa da raiz e da parte aérea e a contagem das inflorescências. Uma doença foi avaliada nos dois primeiros ensaios: a ferrugem, causada por Uromyces striatus, e a segunda foi avaliada nos dois últimos ensaios: murcha de fusário, causada por Fusarium oxysporum f. sp. medicaginis. A severidade das doenças foi avaliada por meio de notas, semanalmente, durante 28 dias ... / Abstract: The atmospheric CO2 concentration, the main gas responsible for intensifying the greenhouse effect, has increased significantly in recent decades. Alfalfa is important forage that can have its characteristics altered by increased atmospheric CO2 concentration, facilitating the occurrence of diseases and enhancing the emission of greenhouse gases after its ingestion by animals. Given this scenario, the objective of this study was to assess the impact of increased CO2 concentration in the air on alfalfa diseases, plant growth and chemical composition. Assays were performed in the field with direct seeding of alfalfa seed cultivar Creole in open top chambers (OTC), adopting the trial randomized block design with three replications. The treatments were: control without OTC, with the concentration of 390 μmol mol-1 of CO2; OTC without CO2 injection with 400 μmol mol-1 of CO2; and OTC injected CO2 with target concentration of 500 μmol mol-1. In the shoots, analyzes were performed to determine dry matter, ash, organic matter, nitrogen in neutral detergent fiber (NDF-N), nitrogen in acid detergent fiber (ADF-N), crude protein and lignin and foliar analysis. In addition to these measures of plant height, stem length and root weight of biomass of the root and shoot and inflorescence. One disease was evaluated during the second trials: rust, caused by Uromyces striatus and one were evaluated during the two last trials: the wilt of fusarium caused by Fusarium oxysporum f. sp. medicaginis. The diseases severity was assessed weekly by notes during 28 days. The defoliation caused by rust was evaluated by the percentage of leaves. Height of stems, the relationship between the length of stem and root, biomass of roots and shoots were higher in the treatment with CO2 injection. Dry matter, ash, organic matter, n- NDF, ADF-n, crude protein and lignin showed no statistical difference between the treatments. The rust ... / Doutor

Orientador: Marcelo Agenor Pavan / Coorientador: Denise Nozaki / Banca: Rumy Goto / Banca: Romulo Fujito Kobori / Resumo: A murcha de fusário, causada pelo fungo de solo Fusarium oxysporum f.sp. lactucae é uma das doenças mais severas que ataca m a cultura da alface em todo o mundo. Em 2011, foram encontrados em uma plantação de alface n os município s de Capão Bonito e Campin as n o estado de São Paulo, sintomas característicos do ataque do patógeno. Plantas sintomáticas foram coletadas para identificação do patógeno. O s exame s em microscóp io óptico revel aram a presença de macroconídios falcados de coloração hialina, microconídi os hialinos unicelulares e testes de patogenicidade revelaram a presença de Fusarium oxysporum f.sp. lactucae . Efetuou - se o re - isolamento do patógeno, completa ndo - se assim o Postulado de Koch . No total, for am encontrados 4 isolados patogê nicos atacando pla ntas de alface. A partir do s isolados identificados , fo ram caracterizada s as variações patogênicas através de diferenciadoras de raça. Para esta finalidade foram utilizadas Patriot ( suscetível às raças 1, 2 e 3 ), Costa Rica ( resistente à raça 1 ; suscetível às raças 2 e 3 ), Summer Green ( suscetível às raças 1 e 3 ; resistente à raça 2 ) e Banchu Red Fire ( suscetível às raças 1 e 3, resistente à raça 2 ) . Os resultados obtidos identificaram a ocorrência da raça 3 de Folac. Este é o primeiro relato de ocorrência desta raça no Brasil . A partir do isolado selecionado como sendo o mais agressivo , e caracterizado como pertencente a raça 3 , r ealizou - se a triagem de genótipos de alface, afim de identificar fontes de resistência para uso em programas de melhoramento . No total de 63 genótipos testados apenas Onondaga, Itha ca, Sudenvil e JP - 11 apresentara m - se como resistente a raça 3 de Fusarium oxysporum f.sp. lactucae / Abstract: The fusarium wilt, caused b y the soil fungus Fusarium oxysporum f.sp. soil lactucae is one of the most severe diseases that attack lettuce crop worldwide. In 2011, were found in a pla nting lettuce in Capão Bonito and Campinas in São Paulo, symptoms characteristic of this pathogen. S ymptomatic plants were collected for pathogen identification. The optical microscope examinations revealed the presence of hyaline staining falcate macroconidia, microconidia unicellular hyaline and pathogenicity tests revealed the presence of Fusarium oxy sporum f.sp. lactucae. We performed the re - isolation of the pathogen, there by supplementing the Koch's postulate. For this purpose were used: Patriot(susceptible to races 1, 2 and 3), Costa Rica (susceptible to races 2 and 3, resistant to race 1); Summer Green (susceptible to races 1 and 3; resistant to race 2) and Banchu Red Fire (susceptible to races 1 and 3, resistant to race 2). The results show the occurrence of race 3 of Folac. This is the first report of the case in Brazil. From the isolated select ed as being the 3 most aggressive, and characterized as belonging to race 3 was held screening of lettuce genotypes in order to identify sources of resistance for use in breeding programs. From of 63 genotypes tested only Onondaga, Ithaca, Sudenvil and JP - 11 were identified as resistant to race 3 of Fusarium oxysporum f.sp. lactucae / Mestre