Orientador: Antonio Goes / Resumo: A ferrugem alaranjada, causada por Puccinia kuehnii, é uma importante doença na cultura da cana-de-açúcar, causando danos econômicos significativos aos produtores. É responsável por 20-40 % de perda em toneladas de cana por hectare e, além disso, provoca redução no teor de sacarose nos colmos. Diante desse contexto, o objetivo desse estudo foi determinar a eficácia dos fungicidas fluxapiroxade, do grupo químico carboxamida, com formulação de fluxapiroxade 300 g L-1 e a formulação contendo o fluxapiroxade + piraclostrobina (167 + 333 g L-1), comparados com os fungicidas padrões piraclostrobina + epoxiconazol (133 + 50 g L-1) e azoxistrobina + ciproconazol (200 + 80 g L-1). Para tal, foram conduzidos quatro experimentos, em condições de campo, no município de Santa Rita do Passa Quatro, estado de São Paulo, entre os meses de novembro de 2012 a abril de 2014. Foram empregadas as cultivares RB72454 e SP813250, plantadas no espaçamento 1,5 m entre linhas. Os tratamentos avaliados e as dosagens (em mL de produto comercial por hectare) foram: fluxapiroxade (167, 233, 300); fluxapiroxade + piraclostrobina (350), epoxiconazol + piraclostrobina (1000) e ciproconazol + azoxistrobina (300). O fungicida ciproconazol + azoxistrobina foi acrescido de 600 mL do óleo mineral Nimbus, enquanto nos demais fungicidas adicionou-se o óleo mineral Assist a 500 mL ha-1. As aplicações dos fungicidas, em número de três, e em intervalos mensais, deram-se mediante pulverizador costal pressurizado a CO2, ... (Resumo completo, clicar acesso eletrônico abaixo) / Mestre

Orientador: Edson Luiz Furtado / Banca: Celso Luis Marino / Banca: Alfredo Seite Urashima / Resumo: Um dos maiores problemas enfrentados pelo setor florestal, no Brasil, tem sido a ocorrência da ferrugem do eucalipto causada por Puccinia psidii Winter, devido a sua severidade em plantações de procedências muito suscetíveis, com menos de dois anos de idade, onde a produtividade das plantas atacadas é bastante reduzida. Devido a grande importância da cultura de Eucalyptus no Brasil e no mundo empresas do setor florestal têm buscado, através de programas de melhoramento genético, reduzir as perdas de produção e atender a demanda do mercado de papel e celulose. No presente trabalho, mudas de Eucalyptus pertencentes a uma geração F1, provenientes do cruzamento controlado entre os parentais: C0 (resistente) e VR (suscetível), foram inoculadas com Puccinia psidii em casa de vegetação e acompanhadas até o aparecimento dos sintomas da ferrugem. Foram classificadas, em dois grupos, segundo sua resistência como resistentes (ausência de sintomas) e suscetíveis (presença de sintomas e esporulação), cujas amostras de DNA foram comparadas com o uso de marcadores moleculares associado ao método de BSA (Bulked Segregant Analysis). O polimorfismo entre os "bulks" foi geneticamente relacionado ao loco que determina a característica de resistência ou sucetibilidade. Dentre os 720 "primers" testados, 19 foram polimórficos, porém, apenas o marcador AK 01 manteve-se presente, quando testado em todos os indivíduos integrantes do "bulk" e no restante da população e mostra-se localizado a uma distância genética estimada de 20 cM do gene de resistência. / Abstract: One of the biggest problems faced by forest sector in Brazil, has been the ocurrence of specific case of rust in eucalyptus caused by Puccinia psidii Winter, due to its severity in crops from highly susceptible origins, with less than two years of life, where the infected plants yield is extremely reduced. Due to the great importance of the Eucalyptus crop in Brazil and in the world, companies in the forest sector have aimed, through genetic breeding programs, to reduce yield losses and meet the demands of the paper and cellulosis market. On the present study, seedlings of Eucalyptus from an F1 generation, bred from controlled crossing between parents C0 (resistant) and VR (susceptible), were innoculated with Puccinia psidii in a greenhouse and followed until the rust symptoms appeared. They were classified into two groups, according to their reaction in: resistant (absence of symptoms) and susceptible (presence of symptoms and buds), whose DNA samples were compared using mollecular markers associated to the BSA (Bulked Segregant Analysis) method. The polymorphism among the "bulks" was genetically characteristic. Among the 720 tested "primers", 19 were polymorphic. But, only the AK01 marker kept present, when tested in all individuals who composed the "bulk" and in the rest of the population and it was shown as located in an estimated genetic distance of 20 cM from the resistance gene. / Mestre

Call number: LD2668 .T4 1986 C374 / Master of Science / Plant Pathology

Orientador: Antonio de Goes / Resumo: A ferrugem alaranjada da cana-de-açúcar (FA), causada por Puccinia kuehnii, é responsável por superior a 40% na produtividade de genótipos de cana-de-açúcar suscetíveis e intermediários. Nesse estudo foram realizados três experimentos. No experimento E1 foi avaliado o efeito do número de aplicações de fungicida piraclostrobina + epoxiconazole (PE) no município de Olímpia-SP, em E2 foi avaliado o efeito do número de aplicações de fungicida piraclostrobina + epoxiconazole (PE) no município de Catigua-SP, ambos em épocas distintas, e em E3 foi avaliado o efeito do volume de calda de PE no controle da doença. A partir dos dados obtidos nos experimentos E1 e E2, foi também avaliada a viabilidade econômica do controle da FA da cana-de-açúcar. Os experimentos foram realizados em dois locais, Olímpia e Catiguá, Estado de São Paulo, sendo empregada a cultivar SP81-3250, em quarto ciclo, após o terceiro corte, em estádio de desenvolvimento (Elongação do colmo; Crescimento intenso; Início do acúmulo de sacarose) da cultura. Em E1 e E2 usou-se o delineamento experimental em blocos ao acaso (DBC), com quatro tratamentos, sendo 0 (testemunha), 1, 2 e 3 aplicações. Cada parcela foi constituída por quatro linhas de 8 metros, espaçadas de 1,5 metros. Foram realizadas sete avaliações, com as quais determinou-se a severidade, a partir das quais foi obtida a área abaixo da curva de progresso da doença (AACPD). Também foi estimado o rendimento de colmos, expresso em tonelada de colmos por hectare... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: The orange rust of sugarcane (FA), caused by Puccinia kuehnii, is responsible for over 40% in the yield of susceptible and intermediate sugarcane genotypes. Three experiments were performed in this study. In the E1 experiment, the effect of the number of applications of fungicide pyraclostrobin + epoxiconazole (PE) in the municipality of Olímpia-SP, in E2, was evaluated the effect of the number of applications of fungicide pyraclostrobin + epoxiconazole (PE) in the municipality of Catigua-SP, both at different times, and in E3 the effect of the volume of PE syrup on disease control was evaluated. From the data obtained in experiments E1 and E2, the economic viability of sugarcane FA control was also evaluated. The experiments were carried out at two locations, Olímpia and Catiguá, State of São Paulo, and the cultivar SP81-3250 was used, in the fourth cycle, after the third cut, at the development stage (Elongation of the stem, intense growth; sucrose) of the culture. In E1 and E2, the experimental design in randomized blocks (DBC) was used, with four treatments, being 0 (control), 1, 2 and 3 applications. Each plot was constituted by four lines of 8 meters, spaced of 1.5 meters. Seven evaluations were performed, with which the severity was determined, from which the area under the disease progress curve (AACPD) was obtained. The yield of stalks, expressed in ton of stems per hectare (TCH), was also estimated. In E3 a similar procedure was adopted, whose treatments were repres... (Complete abstract click electronic access below) / Mestre

This study quantified the frequency of simple versus complex races of Puccinia striiformis Westend. in mixtures of wheat cultivars possessing different race-specific resistance genes. A simple race of a pathogen can infect only one component, and a complex race of the pathogen can infect two or more components of an intraspecific plant mixture. The treatments were designed so that the race that was complex changed depending on the host mixture, thus enabling us to observe the influence of pathogen complexity in different host genetic backgrounds. Six cultivar mixtures and one pure stand of winter wheat were inoculated with three races of P. striiformis (CDL 27, CDL 29, and CDL 41) at two locations for two seasons. Potted plants of three winter wheat cultivars (Paha, Tres, and Tyee) that were each susceptible to one of the three races of the pathogen were used to sample the pathogen during the field epidemics. Disease incidence on the differential cultivars was used to calculate the proportion of the three races in each treatment. The specific cultivars included in the mixtures influenced the frequencies of the three races. Increasing the number of virulent races in a mixture reduced the frequency of the complex race relative to the other two races. When two of the races (races 29 and 41) were complex on the same mixture, location had an effect on which of the races was more frequent. When race 29 was the complex race in the mixture, it was more frequent than when race 41 was the complex race. The results suggest that environmental interactions, genetic background of the pathogen race, host composition, and interaction among pathogen races may be as important in determining race frequencies in mixtures as is stabilizing selection sensu Vanderplank (1968). / Graduation date: 1993

No description available.

Nineteen cultivars and fourteen breeding lines were evaluated for partial resistance to crown rust Puccinia coronata race 264. Multivariate statistical methods such as principal component and cluster analyses were employed to identify significant resistance parameters and to group oat genotypes with similar rust resistance characteristics. This involved two separate investigations consisting of two experiments each, the first experiment conducted under field conditions and the second conducted under growth bench conditions. From both of the investigations a group of oat genotypes with high partial resistance to P. coronata race 264 was obtained. These are OA 712-17, OA 712-33, Glen, Woodstock, QO 220.13, and QO 574.21. These oat genotypes are currently being used as parents in crosses in the Macdonald Campus of McGill University oat breeding program.

No description available.

No description available.

Stripe rust (Puccinia striiformis f. sp. hordei) is a serious disease of barley that can cause up to 70% yield loss in susceptible varieties. The fungus is moving northward, threatening major barley production areas in the US, where most cultivars are susceptible. Fungicides are available for control of stripe rust, but economic and environmental considerations favor genetic resistance. Two stripe rust resistance quantitative trait loci (QTLs) located in chromosomes 4 and 7 have previously been reported. One hundred and ten doubled haploid progeny from a stripe rust susceptible x resistant cross were derived using the Hordeum bulbosum technique and phenotyped for agronomic and malting quality traits in order to assess the importance of linkage drag associated with the mapped stripe rust resistance QTLs. Data on 33 markers were combined with phenotypic data for QTL analysis. A molecular marker-assisted backcross program was implemented to initiate the transfer of the stripe rust resistance loci into susceptible US germplasm. No negative QTLs for agronomic or malting quality traits were detected within or adjacent to the intervals that were targeted for marker-assisted selection. A minor leaf rust resistance QTL, however, was found adjacent to the stripe rust locus on chromosome 7. Linkage drag in this region could operate in favor of the breeder. Epistatic interaction between the two stripe rust resistance QTLs confirms the necessity of introgressing both chromosome intervals. / Graduation date: 1994