The aim of this work is the accurate diagnosis of the Puccinia species of the selected turf grass species under field and laboratory conditions and evaluate influences on the intensity of occurrence. The laboratory tests will be recommended for the best stage of plants to artificial infection. The experiment was carried out in collaboration with SŠ Větrov. In the two-year follow-up (in 2011 and 2012) were at particular times of samples of infected plants, which were then evaluated microscopically. And at the same time experimental work was carried out in laboratory conditions (artificial infection) in plant material of the same origin and assessed degree assault with a precise diagnosis of the type of pathogen. Between 2011 and 2012, was higher occurence stem rust than crown rust.. From a total of 514 tests was stem rust in 379 cases, while crown rust in only 40 cases. In 95 samples was observed incidence of both simultaneously rust and mildew spores remaining plants were discovered. Greenhouse resistance tests were performed on younger plants (3 sheets) and older (6 sheets) in 16 variants, of which 4 were control. Infected leaves were spray uredispor with talc and injected with an aqueous suspension followed by looking drops and were then sealed under insulators at 23 ° C for 24 - 48 hours.

No description available.

Exserohilum turcicum, Phaeosphaeria maydis, Bipolaris maydis, Puccinia polysora, Puccinia sorghi and maize streak virus were the most serious maize pathogens found in Kenya during a 1995/96 survey of 65 farms representing all the agro-ecological zones. Exserohilum turcicum - induced blight was observed in all maize producing areas with disease incidence reaching over 45%. Lesions were sometimes over 400 mm long by 25 mm in width. Southern leaf blight caused by Bipolaris maydis was most severe in the Kenyan maize granary located in the highlands west of the Rift Valley where it occurred alone or with Phaeosphaeria maydis leaf spot. Incidences of over 75% were recorded for southern leaf blight and Phaeosphaeria maydis leaf spot in western Kenya and over 85% for Phaeosphaeria maydis leaf spot in Thika, Nyeri, Muranga and Kirinyaga Districts of Central Province. Common rust caused by Puccinia sorghi was equally severe in the areas of Molo, Njoro and Bahati in Nakuru District with severity levels of over 65%. Lowland rust caused by Pucinia polysora was important in the coastal region with over 75% disease severity in Kwale District. Traces of lowland rust were observed in Kirinyaga District. Maize streak virus was severe in the Lake Victoria region of western Kenya, central areas of Kenya and in the Coast. This disease was severe where Napier grass (Pennisetum purpureum) with streak like symptoms was near the infected maize plots. Individual cultures of Exserohilum turcicum were not appreciably different in appearance but varied in growth rates at 22oC. A total of nineteen isolates of Exserohilum turcicum were classified into races using the Ht gene bearing maize differential inbred lines. Three isolates were race 0, three were race 1, one was race 2, one was race 3, two isolates were race 12, and eight did not fit in the known classification. These were named and grouped as k1, k2 and k3. The k3 race was virulent to HtN gene only. Four Kenyan and two American lines were inoculated with eight isolates of Exserohilum turcicum. All the Kenyan lines were susceptible to the isolates used. Tables of means comparisons and figures for disease occurrence and severity are provided. This is the first time disease prevalence and severity has been documented for maize in Kenya. / Ph. D.

Orientador: Edson Luiz Furtado / Banca: Dirceu Maximino Fernandes / Banca: Waldir Cintra de Jesus Junior / Banca: Hilário Antonio de Castro / Banca: Magali Ribeiro da Silva / Resumo: A cultura do eucalipto é uma das mais importantes do Brasil, constituindo-se em fonte de energia renovável e madeira, além de importantes processos agroindustriais para produção de celulose, papel entre outros. O eucalipto é infectado por uma diversidade de patógenos, principalmente fungos, desde o viveiro até em plantios adultos. O modelo de produção predominante é o monocultivo, adensado e intensamente adubado (adubação de base e duas a três coberturas). Em espécies/clones de eucalipto suscetíveis à Puccinia psidii, a ocorrência de epidemias é observada em condições climáticas favoráveis. Dessa forma, espera-se que o plantio consorciado com uma ou mais espécies não hospedeiras, a intensidade desta doença deva ser menor, devido a barreira física criada e dificulte a disseminação das estruturas reprodutivas do referido patógeno, diluindo o inóculo. Da mesma forma, o aumento do espaçamento também pode dificultar o estabelecimento do patógeno e, um plantio consorciado com uma espécie arbórea leguminosa que permita a fixação biológica de nitrogênio pode levar a redução da aplicação de adubos na forma química devido a ciclagem de nutrientes no sistema. Diante do exposto, os objetivos deste estudo foram: comparar o monocultivo de um clone oriundo da hibridação entre Eucalyptus grandis x E. urophylla e o cultivo do mesmo consorciado com a leguminosa Acacia mangium, com e sem adubação, em dois espaçamentos, quanto a intensidade da ferrugem e, crescimento das plantas (altura, diâmetr... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract:The eucalypt cultivation is one of the most important in Brazil, constituting in source of renewable energy and wood, as well as important agro-industrial processes for the cellulose production, paper and others. The eucalypt is infected by a variety of pathogens, mainly fungus, from the plant nursery to adult cultivation. The predominant production model is the monoculture, densely one and intensively fertilized (basic fertilization and two to three coverages).In eucalypt species/clones susceptible to Puccinia psidii, the occurrence of epidemics is observed in favorable climate conditions. Thus, it is expected that the combined cultivation with one or more non-host species, the intensity of this disease should be lower, due to the physical barrier created not to facilitate the dissemination of the reproductive structures of this pathogen, diluting the inoculum. Similarly, the increased spacing cannot also facilitate the pathogen establishment and a combined cultivation with a leguminous arboreal species allowing the biological fixation of nitrogen can lead to the reduction of the fertilizer application in chemical form due to the cycling of nutrients in the system. Based on the above, the objectives of this study were: to compare the monoculture of a clone from the hybridization between Eucalyptus grandis x E. urophylla and the same combined cultivation with the leguminous Acacia mangium, with and without fertilization in two spacing, about the rust intensity and the plant growth ( height, diameter at breast height, volume and biomass). Among the factors tested, the use fertilization at the cultivation was the most relevant, affecting the disease intensity, as well as the variables of the evaluated growth. Up to the age of two, acacia plants are on the lower layer when combined with eucalypt, thus failing to establish an efficient physical barrier for the pathogen. The same effect was not ... / Doutor

Submitted by Amauri Alves (amauri.alves@ufv.br) on 2015-10-29T14:11:46Z No. of bitstreams: 1 texto completo.pdf: 1548533 bytes, checksum: 5094924f4809fb55ba1e1653ab6f4f77 (MD5) / Made available in DSpace on 2015-10-29T14:11:46Z (GMT). No. of bitstreams: 1 texto completo.pdf: 1548533 bytes, checksum: 5094924f4809fb55ba1e1653ab6f4f77 (MD5) Previous issue date: 2015-02-26 / Conselho Nacional de Desenvolvimento Científico e Tecnológico / Designou-se, neste trabalho, o epítipo de Puccinia psidii Winter, originário de Psidium guajava para servir como referência para futuros estudos taxonômicos e moleculares do fungo. Esta ferrugem é considerada autoécia e macrocíclica, com a fase de pícnio desconhecida e com poucas informações sobre a formação, condição nuclear e o papel dos basidiósporos no ciclo vital de P. psidii. Assim, a partir de estudos citológicos, encontrou-se que após a fusão nuclear e migração do núcleo diplóide do teliósporo para o metabasídio ocorre meiose e originam-se quatro núcleos haplóides. Formam-se septos entre cada um dos quatro núcleos, os quais podem sofrer divisão mitótica e resultar em quatro basidiósporos predominantemente binucleados. A partir de inoculações de basidiósporos em folhas destacadas de Syzygium jambos, observaram-se apressórios lobados rudimentares, mas sem evidência de penetração e infecção. Em outro estudo, seis marcadores microssatélites foram utilizados para analisar a variabilidade genética de 79 isolados de P. psidii coletados em diferentes hospedeiros da Austrália, Nova Caledônia e China. Até o presente momento os isolados são geneticamente uniformes, exceto para algumas mutações pontuais em quatro isolados da Austrália. Ainda que a correlação seja pequena (p< 0.01, r= 0.061), encontrou-se associação entre variabilidade genética de isolados de P. psidii do Brasil, estimada por microssatélites, e os resultados de inoculação cruzadas em diferentes espécies de mirtáceas. Realizou-se o sequenciamento completo e uma breve análise genômica de cinco isolados P. psidii do viiiBrasil e da Austrália. A montagem de cada isolado foi comparada com o isolado VIC42496. Mais de 70% dos contigs de cada isolado que não estavam presente na montagem do isolado VIC 42496 não exibiram homologia com nenhuma sequência depositada no banco de dados do NCBI. Para aquelas sequências que apresentaram similaridade com outras sequências fúngicas, incluindo P. psidii, apenas três contigs foram similares com genes que codificam produtos envolvidos em patogenicidade. / In this study, the epitype of Puccinia psidii Winter from Psidium guajava was designed to serve as reference for future taxonomic and molecular studies of the fungus. This rust is it considered autoecious and macrocyclic, but lacking pycnium and with little knowledge about the formation, nuclear condition and the role of basidiospores in the life cycle of P. psidii. Thus, cytological studies showed that after nuclear fusion the diploid nucleus migrated into the metabasidium and underwent meiotic division resulting in four haploid nuclei. Septum was formed between each nucleus, which can undergo mitotic division and result in four basidiospores mainly binucleate. After inoculations on detached leaves of Syzygium jambos, rudimentary lobate apressoria were observed, but with no evidence of penetration and infection. In another study, six microsatellite markers were used to analyze the genetic variability of 79 isolates of P. psidii collected from different hosts in Australia, New Caledonia and China. Up to now it was found that isolates are genetically uniform, except for a few point mutations in four isolates from Australia. Although the correlation is low (p <0.01, r = 0.061), there was an association between the genetic variability of isolates of P. psidii from Brazil, estimated by microsatellites, and the results of cross-inoculation on different Myrtaceae species. Genome sequencing of five isolates of Puccinia psidii from Brazil and Australia and a brief genomic analysis among them was provided. The assembly of each isolate was compared to VIC 42496. The analysis reveled that more than 70% of the contigs of xeach isolate that was not present on assembly of VIC42496 had no significant homology (no hits) to anything currently residing in the fungal genome databases. For those contigs that displayed similar to fungal sequences, including P. psidii, only three contigs matched with genes coding for products that could be involved in pathogenicity.

Thesis (M.S.)--Oregon State University, 2010. / Printout. Includes bibliographical references (leaves 58-68). Also available on the World Wide Web.

Thesis (Ph. D.)--University of Wisconsin-Madison, 1974. / Typescript. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references (leaves 135-140).

No description available.

The aim of the thesis is evaluation of occurence of rusts on the selected types of grass, their specific diagnosis and valorization of their influence on the important agricultural qualities. The experiment was carried out in a cooperation with SS Větrov. In a two-year period (in 2009 and 2010) the samples of infested plants, which were subsequently evaluated microscopically, were taken. The ascertained results were processed through the Kruskal-Wallis test and the Independent Group T-Test. In 2009 and 2010 the occurrence of stem rust on the tested types of grass was significantly higher than occurence of crown rust. From the total number of 513 tests stem rust was found in 353 cases, whereas crown rust was found only in 103 cases. In 27 samples the occurrence of both types of rusts was found and there was no occurence found on the rest of the plants. The results show that in our climatic conditions stem rust becomes the most frequent pathogen which causes rustiness of grass. In 2010 the results of turf experiments proved that the selection of genotype of perenne reygrass with a lower infestation by stem rust had a positive impact on health conditions and better appearance of the offspring of the selected plans. Effectivenes of selection was confirmed. Among the tested materials there were chosen very predisposed genotypes which could be useful as the infectious material in the planned greenhouse tests for the resistance against rusts. Currently, we have also been abble to recognize the genotypes which are relatively resistant against particular rusts. If their resistance is confirmed in the following period, they might be used as donors of resistance in xenogamy and as immune standards in tests. The introduced results from the first stage of cooperation are only preliminary and it will be necessary to verify them at the following stages.

Stripe rust of wheat, caused by Puccinia striiformis f. sp. tritici (Pst), is one of the most devastating diseases of wheat worldwide. Selection pressure on the pathogen population may result in a rapid shift to races virulent on wheat genotypes with specific resistance genes. For successful stripe rust management, it is important to monitor the virulence spectrum of the pathogen to detect new races. The purpose of this research was to survey Saskatchewan fields to determine the prevalence of stripe rust, characterize the race structure of Pst in western Canada and to determine the genotypic diversity of the pathogen population. Race characterization was performed by inoculating 27 near-isogenic wheat lines carrying 28 known resistance genes, four supplemental cultivars and one triticale cultivar with 61 genetically uniform Pst isolates from western Canada. Whole genome sequencing of pathogen isolates was conducted, using the Illumina HiSeq2500 platform and polymorphisms were assessed by single nucleotide polymorphism (SNP) variants. Characterization of Pst isolates identified 33 races of the pathogen. Genes Yr5, Yr15 and YrSP conditioned resistance against all isolates tested and all isolates were virulent on Yr6, Yr7, Yr9, Yr18, Yr28, Yr29 and Yr31. Variation for virulence was observed among isolates on Yr10, Yr24, YrTye, YrSu, Yr3 and Yr4. The analyses of virulence profiles divided the 61 isolates into four sub-populations or groups. These four sub-populations were distinct from each other in terms of virulence spectrum and year of collection. The Pst population in Alberta had greater diversity in terms of virulence compared with the Saskatchewan population. Diversity at the genome level was not observed to be related to geographic location or virulence phenotypes of the isolates. The SNP data revealed four sub-populations in the western Canadian Pst population. Genomic analyses of 48 Pst isolates did not reveal any relationship of the four sub-populations with their origin or year of collection. Signs of recombination were detected in the Pst population in western Canada. Genomic analyses differentiated isolates showing signs of recombination from those that did not.