Made available in DSpace on 2016-12-08T16:44:46Z (GMT). No. of bitstreams: 1 PGPV13MA130.pdf: 162031 bytes, checksum: 6225aa759350de534e1b4790835b40a1 (MD5) Previous issue date: 2013-11-23 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / Diseases as rotten seed and damping-off cause damages in corn stand. These diseases are more common in the southern region, for the sowing in cold soil. It increases during the period between sowing and seedling emergence, which contributes to the infection by pathogens associated with seed and/or in the soil pathogens. The Chemical Seeds treatment (ST) with fungicide can be an alternative to control these pathogens. The aim of this study was to quantify the mix of estrobilurin and carboxamides with moléculas already used on seed treatment against Fusarium verticillioides and Pythium ultimum beyond the effect of these on the emergence and rate emergence of plants, stalk rot incidence and barren plants and yield. The field experiments were carried out in the season of 2010/11 and 2011/12, in the locations of Xanxerê, São Domingos and Lages in Santa Catarina. It was evaluated the percentage of emerged plants, emergence rate speed, barren plants and stem rotting incidence and yield. Experiments were also carried out "in vitro" for the F. verticillioides control associated with seed and the seedling protection against P. ultimum in the soil. It was evaluated the chemical control of fungicides belonging benzimidazoles, carboxamides and strobilurin groups, isolated and/or in combination, compared with the standard fludioxonil + metalaxyl-m and in combination with carbendazim + thiram. ST with fungicides fludioxonil + metalaxyl-m + carbendazim + thiram and fludioxonil + metalaxyl-m + azoxystrobin + thiabendazole resulted in higher percentage of emerged plants and emergence rate speed in wet and cold soil conditions. As there was an increase in soil temperature it increased the emergence rate speed of plants, 3 regardless of the ST. Seeds treatment with fungicides reduced the stem rotting incidence in this trial with sowing on fallow, however in trials it was sown on oat straw it had no effect. In subsequent sowing, there was a reduction in barren plants incidence, wich was also significantly reduced by ST, indicating that the two factors have an effect on this parameter. The ST did not increase the yield in the trials in São Domingos and Lages, while the experiment was carried out in Xanxerê showed difference in just one hybrid evaluated. The fungicides fludioxonil + metalaxyl-m + carbendazim + thiram and fludioxonil + metalaxyl-m + azoxystrobin + thiabendazole + abamectin showed potential for eradication of F. verticillioides in seeds. The fungicide azoxystrobin mixed with fludioxonil + metalaxyl-m reduced the damage caused by P. ultimum. It did not occur an increasing of P. ultimum control efficiency adding sedaxane. The ST is able to control the pathogens F. verticillioides and P. ultimum, increases the emergency and emergency speed of corn plants, reduces the stem rotting incidence and barren plants incidence and under certain conditions increases the yeld / Doenças como podridões de sementes e tombamento de plântulas causam danos no estande da cultura do milho. Estas são de ocorrência comum na região sul, pois a semeadura em solo frio aumenta o período necessário para emergência das plântulas, o que favorece a infecção por patógenos associados a semente e/ou presentes no solo. O tratamento químico de sementes (TS) pode ser uma alternativa no controle desses patógenos. O objetivo deste trabalho foi quantificar a eficácia de misturas de estrobilurinas e carboxamidas com moléculas atualmente empregadas no TS visando controle de Fusarium verticillioides e Pythium ultimum além do efeito destas sobre a emergência e velocidade de emergência de plantas, incidência de podridões de colmo e plantas dominadas e o rendimento de grãos. Foram conduzidos experimentos de campo, nas safras agrícolas de 2010/11 e 2011/12, nos municipios de Xanxerê, Lages e São Domingos, estado de Santa Catarina. Foram avaliadas a porcentagem de plantas emergidas, velocidade de emergência, incidência de plantas dominadas e de podridões da base do colmo e produtividade de grãos. Também foram realizados experimentos in vitro no controle de F. verticillioides associado à semente e na proteção de plântulas contra P. ultimum presente no solo.Testaram-se fungicidas pertencentes aos grupos químicos dos benzimidazóis, carboxamidas e estrobilurinas, isolados e/ou em mistura, comparados com o padrão fludioxonil + metalaxil-m isolado e em mistura com carbendazim + tiram. O TS com os fungicidas fludioxonil + metalaxil-m + carbendazim + tiram e fludioxonil + metalaxil-m + 1 tiabendazole + azoxistrobina sozinho ou em mistura com sedaxane ou abamectina, proporcionou aumento na porcentagem de plantas emergidas e velocidade de emergência em condições de solo úmido e frio. À medida que houve incremento na temperatura do solo aumentou a velocidade de emergência de plantas, independente da presença de TS com fungicidas. O TS com misturas de fungicidas reduziu a incidência de podridões da base do colmo no experimento onde o milho foi semeado sobre pousio, no entanto nos experimentos onde foi semeado sobre palhada de aveia não teve efeito. À medida que a semeadura foi realizada nas épocas subsequentes, ocorreu redução na incidência de plantas dominadas, que também foi reduzida significativamente pelo TS com fungicidas, indicando que os dois fatores tem efeito sobre esse parâmetro. O TS com misturas de fungicidas não incrementou estatisticamente o rendimento de grãos, nos experimentos de São Domingos e Lages, sendo que no experimento conduzido em Xanxerê houve diferença em apenas um híbrido. Os fungicidas fludioxonil + metalaxil-m + carbendazim + tiram e fludioxonil + metalaxil-m + tiabendazole + azoxistrobina + abamectina apresentaram potencial para erradicação de F. verticillioides das sementes. O fungicida azoxistrobina em mistura com fludioxonil + metalaxil-m reduziu os danos causados por P. ultimum. A adição de sedaxane não incrementou a eficiência do tratamento padrão no controle de P. ultimum. O TS é capaz de controlar os patógenos F. verticillioides e P. ultimum, aumentar a emergência e velocidade de emergência, diminuir a incidência de podridões da base do colmo e plantas dominadas e em determinadas condições aumentar o rendimento de grãos

Thesis (M.Sc.)--University of the Witwatersrand, Faculty of Science, School of Botany, 1991 / The vegetation of the Nylsvley Nature Reserve situated in the Northern Transvaal, South Africa. is a semi·arid savanna dominated by Burkea qfricana and Eragrostis paUensf interspersed with patches of Acacia s_pp.and E, ie/t(lnumni(.ma. The Butkea savanna is established on soil which is naturally low in phosphorus while the A,,;acia savanna is established on soU with higber phosphorus levels. Spnres of vesictdar~arbusculat mycorrhizal (VAM) fungi Were extracted from soil samples by wet 8i:¢ving and sucrose ("mttifugation after which they.· were enumerated .and identified. Thirteen VAM species were isolated from the savanna regions. The population was composed of three Gloltlus spp .• four .4cQulosp()ra spp., one .Gigaspora sp., three Scutel!ispora spp. and tWQ species of uncertain identity. Root samples were cleated. and stained with acidic glycerol·tcypan blue and assessed for mycoufMal colonization. Significant positive correlations were indicated. between spore densities ar.d mycorrhizal root infection. The total 81)01:'e popUlation was negntively correlated wiUlavailuble P, organic C, K. Ca. Mg, and pH. ~'tldividual specles differed markedly from the population as a whole in their bltemctions with.,soil facrots, these wem. examined using linear regressions. The VA;M root colonization as assessed b)! the mycorrhizal % WassigIlfijcant!y negativr1v: (forrelated with P white. the frequency % was. negatively correlated. Wilh P and K. .The inter-relatidhs!;tips 'between the d.ifferentVA1\i ,species and enviro~~eiita1 factors were further explored using prinCipal com'ponent ana,lyt;ls. the population structure and the factors affecting the population ate discussed. ..bltemctions with.,soil facrots, these wem. examined using linear regressions. The VA;M root colonization as assessed b)! the mycorrhizal % WassigIlfijcant!y negativr1v: (forrelated with P white. the frequency % was. negatively correlated. Wilh P and K. .The inter-relatidhs!;tips 'between the d.ifferentVA1\i ,species and enviro~~eiita1 factors were further explored using prinCipal com'ponent ana,lyt;ls. the population structure and the factors affecting the population ate discussed. / MN (2017)

京都大学 / 新制・課程博士 / 博士(農学) / 甲第24111号 / 農博第2516号 / 新制||農||1093(附属図書館) / 学位論文||R4||N5402(農学部図書室) / 京都大学大学院農学研究科森林科学専攻 / (主査)教授 北島 薫, 教授 井鷺 裕司, 准教授 東樹 宏和 / 学位規則第4条第1項該当 / Doctor of Agricultural Science / Kyoto University / DGAM

Thesis (MSc)--University of Stellenbosch, 2004. / ENGLISH ABSTRACT: Numerous workers studied the impact of pollutants and agricultural chemicals, containing heavy metals such as copper (Cu), on soil microbes. It was found that elevated soil Cu levels do have a detrimental effect on soil bacterial populations however the filamentous fungi seemed to be less affected. Most of these studies were conducted in soils containing already relatively high Cu levels and the effect of this heavy metal on the nonfilamentous fungi (i.e. yeasts) was never investigated. The aim of this study was therefore to determine the impact of elevated Cu levels on filamentous fungi and yeasts occurring in soils containing relatively low natural Cu levels. A synthetic selective medium containing glucose as carbon source, thymine as nitrogen source, vitamins, minerals and chloramphenicol as anti-bacterial agent (TMV-agar), was used to enumerate ascomycetous and basidiomycetous Cu resistant yeasts in a sample of virgin soil containing ~ 2ppm Cu. Media that were used to enumerate Cu resistant filamentous fungi were malt extract agar, malt extract agar with streptomycin sulfate, maltyeast- extract-peptone agar with chloramphenicol and streptomycin sulfate, benomyl–dichloran-streptomycin medium for the enumeration of hymenomycetous fungi and two selective media for the isolation of mucoralean fungi. Cu resistant fungi able to grow on all of the above mentioned solid media supplemented with 32 ppm Cu occurred in the soil sample. To obtain an indication of the level of Cu tolerance of fungi present in this soil sample, a number of fungal isolates were screened for the ability to grow on a series of agar plates, prepared from glucose-glutamate-yeast extract agar, containing increasing concentrations of Cu. It was found that filamentous fungi and yeasts that were able to grow on this agar medium containing up to 100 ppm Cu were present in the soil. A series of soil microcosms was subsequently prepared from the soil sample by experimentally contaminating the soil with increasing amounts of copper oxychloride, were after fungal populations in the microcosms, including Cu resistant fungi, were monitored using plate counts. At the end of the incubation period, after 245 days, fungal biomass in the microcosms was compared by determining the concentrations of the fungal sterol, ergosterol, inthe soil. Generally, Cu had little impact on the numbers of filamentous fungal colony forming units on the plates, as well as on the ergosterol content of the soil. The numbers of filamentous fungi in the soil, including the Mucorales and hymenomycetes, seemed to be less affected by the addition of copper oxychloride than the numbers of soil yeasts able to grow on TMV-agar. The focus of the next chapter was on the response of yeasts in different soils to elevated levels of Cu in the soil. TMV-agar was used to enumerate yeasts in soil microcosms prepared from four different soil samples, which were experimentally treated with copper oxychloride resulting in Cu concentrations of up to 1000 ppm. The selective medium supplemented with 32 ppm Cu was used to enumerate Cu resistant yeasts in the microcosms. The results showed that the addition of Cu at concentrations ≥ ~1000 ppm did not have a significant effect on total yeast numbers in the soil. Furthermore, it was found that Cu resistant yeasts were present in all the soil samples regardless of the amount of Cu that the soil was challenged with. At the end of the incubation period, yeasts in the microcosms with zero and ~1000 ppm additional Cu were enumerated, isolated and identified using sequence analyses of the D1/D2 600-650bp region of the large subunit of ribosomal DNA. Hymenomycetous species dominated in the control soil, while higher numbers of the urediniomycetous species were found in the soil that received Cu. These observations suggest that urediniomycetous yeasts may play an important role in re-establishing overall microbial activity in soils following perturbations such as the addition of Cu-based fungicides. / AFRIKAANSE OPSOMMING: Vele navorsers het al die impak van besoedelingstowwe en landbouchemikalieë wat swaarmetale soos koper (Cu) bevat, op grond-mikrobes bestudeer. Dit is gevind dat verhoogde Cu vlakke ‘n nadelige effek het op grond-bakteriese populasies, maar dat die filamentagtige fungi geneig is om minder geaffekteer te word. Meeste van hierdie studies is gedoen met gronde wat alreeds relatief hoë Cu vlakke bevat het en die effek van hierdie swaarmetaal op die nie-filamentagtige fungi (d.i. giste) is nooit ondersoek nie. Die doel van hierdie studie was dus om die impak van verhoogde Cu vlakke op filamentagtige fungi en giste in gronde, wat natuurlike lae vlakke van Cu bevat, te bepaal. ‘n Sintetiese selektiewe medium wat glukose as koolstofbron, timien as stikstofbron, vitamiene, minerale asook chloramfenikol as anti-bakteriese agent bevat (TMV-agar), is gebruik om askomisete en basidiomisete Cu weerstandbiedende giste in ‘n monster ongeskonde grond, bevattende ~ 2dpm Cu, te tel. Media wat gebruik is om Cu weerstandbiedende filamentagtige fungi te tel, was mout-ekstrak agar, moutekstrak agar met streptomisiensulfaat, benomiel-dichloran-streptomisien medium vir die tel van hiemenomiseetagtige fungi en twee media vir die isolasie van mukoraliese fungi. Cu-weerstandbiedende fungi wat op al die bogenoemde media, aangevul met 32 dpm Cu, kon groei, het in die grondmonster voorgekom. Om die mate van Cu-weerstandbiedendheid van fungi wat in die grondmonster voorkom, te bepaal, is ‘n getal fungus-isolate op agarplate, voorberei met glukose-glutamaat-gis ekstrak agar, bevattende verhoogde konsentrasies Cu, nagegaan. Daar is gevind dat daar filamentagtige fungi en giste in die grond voorkom wat die vermoë het om op media bevattende 100 dpm Cu te groei. ‘n Reeks grond mikrokosmosse is dus voorberei vanaf die grondmonster deur om dit eksperimenteel te kontamineer met verhoogde hoeveelhede koper oksichloried, waarna die fungus-populasies asook die Cu-weerstandbiedende fungi in die mikrokosmos gemoniteer is deur middel van plaattellings. Aan die einde van die inkubasie periode, 245 dae, is die fungus biomassa in al die mikrokosmosse bereken deur die konsentrasie van die fungus sterool ergosterool te bepaal en dit met mekaar te vergelyk. Oor die algemeen het Cu min impak ten opsigte van diegetal filamentagtige fungi kolonie vormende eenhede die plate, asook op die ergosterool inhoud van die grond gehad. Dit wil voorkom of die getal filamentagtige fungi in die grond, insluitende die Mucorales en die hymenomisete, minder geaffekteer is deur die toediening van koperoksichloried as die aantal grondgiste wat op die TMV-agar kan groei. Die fokus van die volgende hoofstuk was dus op die reaksie wat giste in verskillende grondtipes gehad het op verhoogde Cu in die grond. TMV-agar is gebruik om die getal giste te bepaal in die grond mikrokosmosse van die vier verskillende grondmonsters, wat voorberei is deur om dit eksperimenteel met koper oksikloried te kontamineer tot en met Cu konsentrasies van 1000 dpm. Die selektiewe medium wat gesupplementeer is met 32 dpm Cu, is gebruik om Cu weerstandbiedende giste in die mikrokosmosse te bepaal. Die resultate toon dat die toevoeging van Cu by konsentrasies ≥ ~1000 dpm nie enige beduidende effek op die totale gis getalle gehad het nie. Daar is ook gevind dat daar Cu weerstandbiedende giste in die grond monsters voorkom gekom het ten spyte van die hoeveelheid Cu wat tot die grond toegevoeg is. Aan die einde van die inkubasie periode is die giste wat die die mikrokosmosse bevattende nul en ~1000 dpm Cu getel, geïsoleer en geïdentifiseer deur gebruik te maak van DNA volgorde bepaling van die D1/D2 600-650 bp areas geleë in die groter subeenheid van die ribosonale DNA. Hymenomisete spesies het in die grond kontrole gedomineer, terwyl hoër getalle uredinomisete spesies in die grond met addisionele Cu gevind is. Die resultate dui daarop dat uredinomisete giste dalk ‘n belangrike rol kan speel in die hervestiging van die oorwegende mikrobiese aktiwiteit in grond na skoktoestande soos die aanwending van Cu-gebaseerde fungisiede.

Thesis (MSc (Microbiology))--Stellenbosch University, 2008. / Penicillium is a well‐known cosmopolitan genus with more than 225 accepted species. Species from this diverse genus, in general, are considered to primarily be soil fungi, with decomposition as its main function. Therefore, together with its ubiquitous nature, these species are of great importance in ecosystems, agriculture and biotechnology. However, in South Africa, very little research has been done on this complex genus, as species identification were often found to be problematic, even for experienced taxonomists. This lead to a number of South African studies only mentioning that a Penicillium spp. were isolated, without making any attempt of showing the extent of diversity within the genus from the unique habitats. The present study set out to explore the extent of the species diversity in Penicillium isolated from the Cape Floristic Region, specifically focusing on coastal fynbos soil. Soil samples were collected from this region, at sites situated outside Malmesbury. Four hundred and thirty four Penicillium strains were isolated from soil‐dilutions. The strains were characterized using morphological characters and subsequently placed into 24 morphological groups. There were, also, more or less 40 strains that could not be grouped with any other isolates. Groupings were made according to conidiophore branching patterns which divided the strains into their respective subgenera. Eight species from subgenus Aspergilloides, seven from subgenus Furcatum, eight from subgenus Biverticillium and one from subgenus Penicillium were isolated. The species were further characterized in subsequent chapters. In the second chapter of this thesis, one of the taxonomic groups in subgenus Biverticillium, isolated from coastal fynbos soil, Protea infructescences and on moth‐damaged Riesling grapes in Canada, was examined. This species was characterized using morphology and were found to have several unique characters, such as the very short synnema produced after prolonged incubation. These characters did not conform to descriptions of previously described species. Its novelty was confirmed by an ITS phylogeny and the strains were subsequently described as Penicillium ramulosum prov. nom. with P. cecidicola and P. dendriticumas its sister taxa. In chapter three, a further seven groups belonging to Penicillium subgenus Biverticillium were characterized. These strains were identified as P. minioluteum, P. verruculosum and P. rugulosum‐like, respectively. Four of the groups showed unique morphological characters, with the ITS phylogeny resolving the fynbos strains separate from all previously described species. The strains were, therefore, considered to be new to science and described as P. solicola prov. nom., P. ptychoconidium prov. nom., P. occultum prov. nom. and P. chloroloma prov. nom., respectively. A key to species from subgenus Biverticilliumcluded. is also inPenicillium subgenus Furcatum was the subject of the fourth chapter of this thesis. Our survey found that although the species diversity in this group was not as high as for the other subgenera, it was the group most often isolated in this study. Species were identified as P. janczewskii, P. canescens, P. melinii, P. corylophilum and P. citrinum using morphological characters. One species belonging to subgenus Penicillium, P. expansum, was also isolated and compared to species recorded during a previous survey. Amongst the identified species, were two groups that could not be identified using published keys, with their novelty confirmed by an ITS phylogeny. They are, therefore, described here as P. subturcoseum prov. nom. and P. hemitrachum prov. nom. A key to species in this subgenus is also provided. In Chapter 5 the presence of Penicillium subgenus Aspergilloides, which is characterized by monoverticillate conidiophores, were investigated. Species were identified as P. roseopurpureum, P. restrictum, P. hirayamae and P. toxicarium. Amongst the identified species, were four groups that did not conform to previously described species and are described here as P. brachycaulon prov. nom., P. malacosphaerula prov. nom., P. cumulacinatum prov. nom. and P. vulgaris prov. nom., respectively. The newly described species have been included in a key, together with closely related species and the other species of subgenus Aspergilloides from the fynbos soil. Species identifications in Penicillium is often problematic and South African taxonomists have often not attempt to identify strains down to species level. During this study, Penicillium was found to be well represented in the soil, with a large proportion being previously undescribed. For this reason, a dichotomous and synoptic key to species isolated during this study are provided in the final chapter. This study should thus serve as a basis for further explorations into the diversity and ecological role of this group of organisms in this ecologically mportant biome.

Thesis (MSc)--University of Stellenbosch, 2001. / ENGLISH ABSTRACT: Mucoralean fungi are mostly saprotrophs that are frequently encountered in soil habitats. Using an isolation temperature of circa 25°C, other workers obtained these fungi from a wide diversity of geographical areas in southern Africa. However, it is known that psychrotolerant mucoralean fungi, able to grow at 25°C as well as at 5°C, occur in pristine Alti Mountain Grassland. Nothing is known about the diversity of these psychrotolerant soil fungi in other vegetation types of South Africa. Consequently, in this study, the psychrotolerant fungal taxa and numbers in soil from a vineyard and from pristine Mountain Fynbos were determined using an incubation temperature of 4°C and a complex isolation medium. The latter contained agar, malt extract, peptone, yeast extract, penicillin and streptomycin sulphate. Soil samples were analysed in late summer, autumn and mid-winter. It was found that, for the samples taken in late summer and autumn, the diversity of mucoralean species in the soil differed between fynbos and vineyard. In winter however, no significant difference was detected between the Shannon's diversity indices of mucoralean species in the soil samples taken from the two habitats. It was found that in both soil types, the percentage mucoralean fungi on the plates increased from summer to winter. In addition, the numbers of detectable Morlierella subgenus Morlierella on the plates were higher in winter than in late summer. The diversity of mucoralean species obtained during winter in fynbos and vineyard soil was significantly less than the diversity of these species in Alti Mountain Grassland soil. To determine if the Morlierella subgenus Morlierella isolates from the fynbos and vineyard soil, and those obtained from Alti Mountain Grassland, differ in the ability to grow at low temperatures, the radial growth rate on malt extract agar at 4°C and BOC was determined for each isolate. The results indicate that not only did seasonal changes occur in the taxa within Morlierella subgenus Morlierella, but that the isolates dominating the soil in different seasons also differed in the ability to grow at low temperatures. The percentage of isolates that had reached greater colony diameters after B days of incubation at 4°C, was higher for the isolates obtained in the cold wet month of July than for those obtained in the warmer dryer month of February. Similar results were obtained with the radial growth experiments conducted at BOC. The Morlierella subgenus Morlierella isolates obtained in winter from fynbos and vineyard soil showed less variation in low temperature growth rate than the isolates of this taxon obtained in winter from Alti Mountain Grassland soil during a previous study. This variation corresponds to the greater number (20) of Morlierella subgenus Morlierella species found in the grassland soil. Altogether only seven species of this subgenus was detected during the present study in the fynbos and vineyard soil samples. It was speculated that this difference in diversity between the fynbos and vineyard isolates, and the grassland isolates obtained in a previous study, might have been as a result of differences in the habitat or the enumeration methods used. The phylogenetic relationship between different psychrotolerant isolates of Morlierella subgenus Morlierella originating from the soil of the fynbos, vineyard and Alti Mountain Grassland, was subsequently determine through comparison of ITS regions, within ribosomal RNA repeats. Consequently, 45 psychrotolerant Morlierella subgenus Morlierella isolates originating from the three soil habitats was compared on the basis ITS 1 nucleotide sequence composition and radial growth rate at 4°C. Phylogenetic analyses showed that the isolates could be grouped into two clusters correlating with the ability to grow at low temperatures. Each cluster was further subdivided into two subgroups. It was found that except for one subgroup and the reference strain occurring in another subgroup, all the subgroups contain isolates originating from a single soil habitat. Therefore, the ITS 1 sequence of these fungi seems to indicate the original habitat and ability to grow at low temperatures. This correlation of the ITS sequence with the ecological habitat of a fungus has also been observed by other workers for other fungal groups. / AFRIKAANSE OPSOMMING: Mucoraliese fungi is meestal saprotrofe wat dikwels in grondhabitatte aangetref word. Deur gebruik te maak van 'n isolasietemperatuur van circa 25°C, het ander werkers dié fungi van 'n wye verskeidenheid geografiese gebiede in suidelike Afrika verkry. Dit is egter bekend dat die psigrotolerante mucoraliese fungi, wat in staat is om by 2SoC en ook by SaC te groei, in ongeskonde Alti Berg-Grasland voorkom. Niks is egter bekend oor die diversiteit van dié psigrotolerante grondfungi in ander veldtipes van suidelike Afrika nie. Die psigrotolerante fungustaksa en -getalle in grond van 'n wingerd en van ongeskonde Berg Fynbos is gevolglik in dié studie bepaal deur gebruik te maak van 'n inkubasietemperatuur van 4"C en 'n komplekse isolasiemedium. Laasgenoemde het agar, moutekstrak, peptoon, gisekstrak, penisillien en streptomisiensulfaat bevat. Grondmonsters is in die laatsomer, herfs en midwinter geanaliseer. Daar is 'n verskil gevind tussen die diversiteit van die mucoraliese spesies in die grond van fynbos en dié van wingerd in die monsters wat in die laatsomer en midwinter geneem is. In die winter is daar egter geen beduidende verskil gevind tussen die Shannon diversiteitsindekse van mucoraliese spesies in die grondmonsters wat uit die twee habitatte getrek is nie. In albei grondtipes is daar gevind dat die persentasie mucoraliese fungi op die plate toegeneem het van somer tot winter. Daarby was die aantal waarneembare Morlierella subgenus Morlierella op die plate meer in die winter as in die laatsomer. Die diversiteit van mucoraliese spesies wat in die winter uit fynbos- en wingerdgrond verkry is, was beduidend minder as die diversiteit van dié spesies in Alti Berg-Grasland grond. Om te bepaal of die Morlierella subgenus Morlierella isolate van die fynbos- en wingerdgrond en dié van Alti Berg-Grasland van mekaar verskil ten opsigte van hul vermoë om by lae temperature te groei, is die radiale groeitempo op moutekstrak by 4"C en aoc vir elke isolaat bepaal. Die resultate dui aan dat daar nie alleen seisoenale veranderinge in die taksa binne Morlierella subgenus Morlierella voorkom nie, maar dat die isolate wat tydens verskillende seisoene uit die grond verkry is, ook ten opsigte van hul groeivermoë by lae temperature van mekaar verskil. Die persentasie isolate wat groter kolonie diameters bereik het ná B dae inkubasie by 4°C, was hoër vir die isolate van die koue, nat Juliemaand as vir dié wat in die warmer en droër Februariemaand verkry is. Soortgelyke resultate is verkry met radiale groei-eksperimente wat by BOC gedoen is. Die MortierelIa subgenus MortierelIa isolate wat in die winter uit fynbos- en wingerdgrond verkry is, het In kleiner variasie in hul groeitempo by lae temperature getoon as die isolate in dié takson wat tydens 'n vorige studie in die winter uit Alti Berg-Grasland grond verkry is. Dié variasie stem ooreen met die groter aantal (20) MortierelIa subgenus MortierelIa spesies wat in die graslandgrond gevind is. Slegs sewe spesies van dié subgenus is gedurende die huidige studie in die fynbos- en wingerdgrondmonsters waargeneem. Daar is gespekuleer dat dié verskil in diversiteit tussen die fynbos- en wingerdisolate en die graslandisolate van die vorige studie die gevolg mag wees van verskille tussen die habitat of die enumerasiemetodes wat gebruik is. Die filogenetiese verwantskap tussen verskillende psigrotolerante isolate van MortierelIa subgenus MortierelIa uit die grond van die fynbos, wingerd en Alti Berg-Grasland, is vervolgens bepaal deur 'n vergelyking van interne getranskribeerde spasieerder (ITS) areas, binne ribosomale RNS herhalings. Daar is gevolglik 45 psigrotolerante MortierelIa subgenus MortierelIa isolate uit die drie grondhabitatte met mekaar vergelyk op grond van die basis ITS 1 nukleotied opeenvolgingsamestelling en radiale groeitempo by 4°C. Filogenetiese analises het die isolate in twee groepe verdeel op grond van hul vermoë om by lae temperature te groei. Elke groep is verder in twee subgroepe verdeel. Daar is gevind dat behalwe vir een subgroep en die verwysingstam wat in 'n ander subgroep voorgekom het, elkeen van die subgroepe bestaan het uit isolate wat van 'n enkele grond habitat verkry is. Dit wil dus voorkom of die ITS 1 opeenvolging van dié fungi 'n aanduiding gee van die oorspronklike habitat en die vermoë om by lae temperature te groei. Dié korrelasie tussen die ITS opeenvolging en die ekologiese habitat van 'n fungus is ook deur ander werkers vir ander fungusgroepe waargeneem.

O Brasil se encontra entre os maiores produtores e consumidores mundiais de feijão, o qual representa a principal fonte de proteína vegetal na dieta alimentar de significativa parcela da população. Apesar de apresentar destaque na produção mundial de feijão, a produtividade média brasileira é muito baixa. Na safra das águas de 2002, o Brasil obteve uma produtividade de 926kg.ha-1, valor muito aquém do potencial genético da cultura, que pode chegar a 4.000kg.ha-1. As doenças estão entre os principais fatores que contribuem para a baixa produtividade e o alto risco dessa cultura. As doenças causadas por fungos de solo são um dos fatores de maior contribuição, com destaque para a murcha ou amarelecimento de Fusarium. Alguns estudiosos apontam, como uma das principais causas para a ocorrência e predisposição das plantas a patógenos e insetos-praga, o desequilíbrio nutricional (carência ou excesso) aliado ao estádio fenológico do hospedeiro, além do componente genético. Nas condições do Brasil, ainda são escassos os trabalhos visando ao controle cultural da murcha de fusarium em feijão. Assim, o presente trabalho teve por objetivos: (i) a avaliação do efeito da variação do pH do meio de cultura sobre o desenvolvimento micelial de Fusarium oxysporum f. sp. phaseoli; (ii) a verificação do efeito da variação do pH do meio de cultura, na patogenicidade de Fusarium oxysporum f. sp. phaseoli; e (iii) a verificação e a quantificação dos efeitos das fontes e distribuição da adubação nitrogenada e do tratamento químico das sementes, na incidência e severidade da murcha de fusarium e na produtividade de feijão. Foram avaliadas quatro raças de F. oxysporum f. sp. phaseoli, em função de seis valores de pH in vitro. Em casa-de-vegetação, foram testadas as mesmas quatro raças provenientes do experimento in vitro. E em campo, foram avaliadas duas fontes e cinco combinações de doses de adubação nitrogenada, em relação à incidência da murcha de fusarium e à produtividade de feijão. De acordo com os resultados obtidos neste trabalho, pode-se concluir que: (i) as quatro raças de F. oxysporum f. sp. phaseoli apresentaram reações distintas, em função da variação do pH do meio de cultura; (ii) as raças III e IV apresentaram desenvolvimento mais rápido; (iii) as diferenças proporcionadas pela variação do pH do meio de cultura foram menores que as causadas pelas raças; (iv) a variação do pH do meio de cultura não proporcionou diferenças na patogenicidade das mesmas; (v) apesar de não terem sido observadas diferenças estatísticas entre as raças de F. oxysporum f. sp. phaseoli, a raça I, foi mais patogênica; (vi) o tratamento químico de sementes de feijão, assim como a adubação nitrogenada de feijão, não proporcionou diferenças na população, incidência da murcha de fusarium e produtividade de grãos de feijão; (vii) não houve influência da adubação nitrogenada na população, incidência da murcha de fusarium e produtividade de grãos de feijão; (viii) as fontes e combinações de doses de N, assim como o tratamento químico das sementes, não proporcionaram diferenças nos teores dos macronutrientes e micronutrientes, exceto para o ferro, nas folhas de feijão; e (ix) a adubação nitrogenada com 0+80kg.ha-1 e 10+70kg.ha-1 (semeadura+cobertura) proporcionaram maiores teores de ferro em folhas de feijão. / Brazil is one of the biggest world growers and consumers of common bean, that is one of the main protein sources in the feeding habits of the significantly population plot. Even if present prominence in the world common bean production, the Brazilian yield is very low. In the spring-summer 2002 the yield was about 926 kg.ha-1, a value much lower than the crop genetic potential, that can reach 4,000 kg.ha-1. Between the mainly factors that contribute for the low yield and the unstability of this crop, diseases have an important place. The diseases caused by soil fungi are one of the most important factors, with prominence to the fusarium wilt. Some researchers point the nutritional imbalance (lack or excess) as one of the mainly causes for the occurrence and predisposition of the plants to the pathogens and insects-pests attack, in addition with the plant growing phase and the climate conditions, beyond of the genetics interference. In the Brazilian conditions, there are a few studies that aimed the cultural control of the bean yellows. This study aimed: (i) the evaluation of the culture media pH variation effect at the mycelia development of Fusarium oxysporum f. sp. phaseoli; (ii) the verification of the culture media pH variation effects at the pathogenicity of F. oxysporum f. sp. phaseoli; and (iii) the verification and quantification of the N sources and doses combinations effects at the incidence of fusarium wilt and common bean yield. Four strains of F. oxysporum f. sp. phaseoli were evaluated in relation of six culture media pH values. The same four strains proceeding from the in vitro experiment were tested in a green house experiment. Two sources and five doses combination of nitrogen fertilizaton were evaluated in relation of bean yellows incidence and common beans yield. The results obtained in this study showed that: (i) the four strains of F. oxysporum f. sp. phaseoli showed distinct reactions according the culture media pH variation; (ii) the strains III and IV showed faster development; (iii) the differences caused by the culture media pH variation were smaller than those caused by the strains; (iv) the culture media pH variation did not cause pathogenicity variation; (v) although statistical differences were not observed between the strains of F. oxysporum f. sp. phaseoli, the strain I was the most pathogenic; (vi) the chemical common bean seeds treatment, as well the nitrogen fertilization did not cause differences in the population, fusarium wilt incidence and common bean yield; (vii) the sources and combinations of nitrogen doses, as well the chemical common bean seeds treatment, did not cause differences in the macronutrients and micronutrients content, except for iron in the common bean leaves; and (viii) the nitrogen fertilization with 0+80kg.ha-1 and 10+70kg.ha-1 (planting and cover) caused greater iron content in common bean leaves.

Bibliography: leaves 140-158 / ix, 158 leaves, [23] leaves of plates : ill., 1 map ; 30 cm. / Title page, contents and abstract only. The complete thesis in print form is available from the University Library. / Thesis (Ph.D.1985) Dept. of Plant Pathology, University of Adelaide

Thesis (Ph. D.)--University of Wisconsin--Madison, 1919. / Title from added collective thesis title page. Part 1 reprinted from Phytopathology, vol. 4, no. 4 (Aug. 1914), p. [323]-326, plate XXI ; Part 2 reprinted from Phytopathology, vol. IX, no. 2 (Feb. 1919), p. [93]-103, plate IX ; Part 3: Bulletin / United States Department of Agriculture, no. 818 (5 Jan. 1920) (see OCLC #16627505), 14 p., V p. of plates ; Part 4: Bulletin / United States Department of Agriculture, no. 842 (7 Sept. 1920) (see OCLC #16627722), 40 p., VI p. of plates. Includes bibliographical references.

O Brasil se encontra entre os maiores produtores e consumidores mundiais de feijão, o qual representa a principal fonte de proteína vegetal na dieta alimentar de significativa parcela da população. Apesar de apresentar destaque na produção mundial de feijão, a produtividade média brasileira é muito baixa. Na safra das águas de 2002, o Brasil obteve uma produtividade de 926kg.ha-1, valor muito aquém do potencial genético da cultura, que pode chegar a 4.000kg.ha-1. As doenças estão entre os principais fatores que contribuem para a baixa produtividade e o alto risco dessa cultura. As doenças causadas por fungos de solo são um dos fatores de maior contribuição, com destaque para a murcha ou amarelecimento de Fusarium. Alguns estudiosos apontam, como uma das principais causas para a ocorrência e predisposição das plantas a patógenos e insetos-praga, o desequilíbrio nutricional (carência ou excesso) aliado ao estádio fenológico do hospedeiro, além do componente genético. Nas condições do Brasil, ainda são escassos os trabalhos visando ao controle cultural da murcha de fusarium em feijão. Assim, o presente trabalho teve por objetivos: (i) a avaliação do efeito da variação do pH do meio de cultura sobre o desenvolvimento micelial de Fusarium oxysporum f. sp. phaseoli; (ii) a verificação do efeito da variação do pH do meio de cultura, na patogenicidade de Fusarium oxysporum f. sp. phaseoli; e (iii) a verificação e a quantificação dos efeitos das fontes e distribuição da adubação nitrogenada e do tratamento químico das sementes, na incidência e severidade da murcha de fusarium e na produtividade de feijão. Foram avaliadas quatro raças de F. oxysporum f. sp. phaseoli, em função de seis valores de pH in vitro. Em casa-de-vegetação, foram testadas as mesmas quatro raças provenientes do experimento in vitro. E em campo, foram avaliadas duas fontes e cinco combinações de doses de adubação nitrogenada, em relação à incidência da murcha de fusarium e à produtividade de feijão. De acordo com os resultados obtidos neste trabalho, pode-se concluir que: (i) as quatro raças de F. oxysporum f. sp. phaseoli apresentaram reações distintas, em função da variação do pH do meio de cultura; (ii) as raças III e IV apresentaram desenvolvimento mais rápido; (iii) as diferenças proporcionadas pela variação do pH do meio de cultura foram menores que as causadas pelas raças; (iv) a variação do pH do meio de cultura não proporcionou diferenças na patogenicidade das mesmas; (v) apesar de não terem sido observadas diferenças estatísticas entre as raças de F. oxysporum f. sp. phaseoli, a raça I, foi mais patogênica; (vi) o tratamento químico de sementes de feijão, assim como a adubação nitrogenada de feijão, não proporcionou diferenças na população, incidência da murcha de fusarium e produtividade de grãos de feijão; (vii) não houve influência da adubação nitrogenada na população, incidência da murcha de fusarium e produtividade de grãos de feijão; (viii) as fontes e combinações de doses de N, assim como o tratamento químico das sementes, não proporcionaram diferenças nos teores dos macronutrientes e micronutrientes, exceto para o ferro, nas folhas de feijão; e (ix) a adubação nitrogenada com 0+80kg.ha-1 e 10+70kg.ha-1 (semeadura+cobertura) proporcionaram maiores teores de ferro em folhas de feijão. / Brazil is one of the biggest world growers and consumers of common bean, that is one of the main protein sources in the feeding habits of the significantly population plot. Even if present prominence in the world common bean production, the Brazilian yield is very low. In the spring-summer 2002 the yield was about 926 kg.ha-1, a value much lower than the crop genetic potential, that can reach 4,000 kg.ha-1. Between the mainly factors that contribute for the low yield and the unstability of this crop, diseases have an important place. The diseases caused by soil fungi are one of the most important factors, with prominence to the fusarium wilt. Some researchers point the nutritional imbalance (lack or excess) as one of the mainly causes for the occurrence and predisposition of the plants to the pathogens and insects-pests attack, in addition with the plant growing phase and the climate conditions, beyond of the genetics interference. In the Brazilian conditions, there are a few studies that aimed the cultural control of the bean yellows. This study aimed: (i) the evaluation of the culture media pH variation effect at the mycelia development of Fusarium oxysporum f. sp. phaseoli; (ii) the verification of the culture media pH variation effects at the pathogenicity of F. oxysporum f. sp. phaseoli; and (iii) the verification and quantification of the N sources and doses combinations effects at the incidence of fusarium wilt and common bean yield. Four strains of F. oxysporum f. sp. phaseoli were evaluated in relation of six culture media pH values. The same four strains proceeding from the in vitro experiment were tested in a green house experiment. Two sources and five doses combination of nitrogen fertilizaton were evaluated in relation of bean yellows incidence and common beans yield. The results obtained in this study showed that: (i) the four strains of F. oxysporum f. sp. phaseoli showed distinct reactions according the culture media pH variation; (ii) the strains III and IV showed faster development; (iii) the differences caused by the culture media pH variation were smaller than those caused by the strains; (iv) the culture media pH variation did not cause pathogenicity variation; (v) although statistical differences were not observed between the strains of F. oxysporum f. sp. phaseoli, the strain I was the most pathogenic; (vi) the chemical common bean seeds treatment, as well the nitrogen fertilization did not cause differences in the population, fusarium wilt incidence and common bean yield; (vii) the sources and combinations of nitrogen doses, as well the chemical common bean seeds treatment, did not cause differences in the macronutrients and micronutrients content, except for iron in the common bean leaves; and (viii) the nitrogen fertilization with 0+80kg.ha-1 and 10+70kg.ha-1 (planting and cover) caused greater iron content in common bean leaves.