Dissertations / Theses on the topic 'Stalk rot'

Doctor of Philosophy<br>Department of Agronomy<br>Tesfaye Tesso<br>Fusarium stalk rot and charcoal rot caused by Fusarium thapsinum and Macrophomina phaseolina respectively are devastating global diseases in sorghum that lead to severe quality and yield loss each year. In this study, three sets of interrelated experiments were conducted that will potentially lead to the development of resistance based control option to these diseases. The first experiment was aimed at identifying sources of resistance to infection by M. phaseolina and F. thapsinum in a diverse panel of 300 sorghum genotypes. The genotypes were evaluated in three environments following artificial inoculation. Out of a total of 300 genotypes evaluated, 95 genotypes were found to have resistance to M. phaseolina and 77 to F. thapsinum of which 53 genotypes were resistant to both pathogens. In the second experiment, a set of 79,132 single nucleotide polymorphisms (SNPs) markers were used in an association study to identify genomic regions underlying stalk rot resistance using a multi-locus mixed model association mapping approach. We identified 14 loci associated with stalk rot and a set of candidate genes that appear to be involved in connected functions controlling plant defense response to stalk rot resistance. The associated SNPs accounted for 19-30% of phenotypic variation observed within and across environments. An analysis of associated allele frequencies within the major sorghum subpopulations revealed enrichment for resistant alleles in the durra and caudatum subpopulations compared with other subpopulations. The findings suggest a complicated molecular mechanism of resistance to stalk rots. The objective of the third experiment was to determine the functional relationship between stay-green trait, leaf dhurrin and soluble sugar levels and resistance to stalk rot diseases. Fourteen genotypic groups derived from a Tx642 × Tx7000 RIL population carrying combinations of stay-green quantitative trait loci were evaluated under three environments in four replications. The stg QTL had variable effects on stalk rot disease. Genotypes carrying stg1, stg3, stg1,3 and stg1,2,3,4 expressed good levels of resistance to M. phaseolina but the combination of stg1 and stg3 was required to express the same level of resistance to F. thapsinum. Other stg QTL blocks such as stg2 and stg4 did not have any impact on stalk rot resistance caused by both pathogens. There were no significant correlations between leaf dhurrin, soluble sugar concentration, and resistance to any of the pathogens.

Colleotrichum graminicola is the causal agent of anthracnose stalk rot, and is one of the most common and aggressive pathogens of maize. The goal of my Ph.D. project was to contribute to a better understanding of the biology of the interaction between C. graminicola and its host. C. graminicola produces two type of asexual spores: one is produced on the surface of infected tissues and is thought to be involved in the spread of the disease in the field. The second type of spore, oval in shape, is produced inside the infected plant tissues, and was believed to be involved in the movement of the pathogen inside the plant tissues via the vascular system. I tested this hypothesis with both cytological and molecular approaches. I used strains of C. graminicola expressing green fluorescent proteins (GFP) to inoculate wounded plants, and followed the development of the pathogen over time. This study revealed that C. graminicola is not a vascular pathogen. C. graminicola primarily moved through the rind and vascular fibers. Oval spores were produced in colonized parenchyma cells and remained dormant, and did not appear to be involved in the movement of the pathogen, at least during the early stages of the disease development. I also studied pathogen ingress in the absence of a wound. I inoculated unwounded plants with the GFP expressing strains. C. graminicola efficiently colonized the epidermis and, given enough time, penetrated and colonized the deeper parenchyma tissues, after first moving through the fibers. To further test the role of sporulation in colonization of maize tissues, I used targeted mutagenesis to disrupt a major gene known to regulate sporulation and vegetative growth in several other fungi. The gene Cgg1, orthologue of the A. nidulans fadA, was disrupted using the split marker method. The Cgg1 mutants were less pathogenic than the wildtype to wounded plants. This was associated with an apparent increase in production of spores and primary infection hyphae. This suggests that Cgg1 signaling pathway plays a role in maximizing colonization of host tissues, and that this involves negative regulation of sporulation and primary hyphae production in planta.

Master of Science<br>Department of Agronomy<br>Tesfaye Tesso<br>Sorghum [Sorghum bicolor (L.) Moench] is listed as one of the potential feedstock sources for biofuel production. While sorghum grain can be fermented into ethanol in a similar way as maize, the greatest potential of the crop is based on its massive biomass and sugar rich juices. Thus development of the crop as alternative energy source requires improvement of these traits. The objectives of this study were (1) to determine the mode of inheritance of traits related to ethanol production and identify suitable genetic sources for use in breeding programs, and (2) to evaluate the potential of low lignin mutations for biomass feedstock production and assess biotic stress risks associated with deployment of the mutations. The study consisted of three related experiments: (i) estimating the combining ability of selected sweet and high biomass sorghum genotypes for biofuel traits and resistance to stalk lodging, (ii) determine the impact of brown mid-rib mutations on biofuel production and their reaction to infection by Macrophomina phaseolina and Fusarium thapsinum, and (iii) assess the reaction of low lignin mutants to green bug feeding. In the first experiment six sorghum genotypes of variable characteristics (PI193073, PI257602, PI185672, PI195754, SC382 and SC373) were crossed to three standard seed parent lines ATx3042, ATx623 and ATx399. The resulting hybrids and the parents were evaluated at four locations, three replications during 2009 and 2010 seasons. Data were collected on phenology, plant height, juice yield, °brix score and biomass production. In the second experiment, two brown mid-rib mutations (bmr6 and bmr12) and their normal versions were studied in four forage sorghum backgrounds (Atlas, Early Hegari, Kansas Collier and Rox Orange). The experiment was planted in four replications and at 14 d after flowering five plants in a plot were artificially infected with F. thapsinum and another five with M. phaseolina. The plants were harvested and rated for disease severity (lesion length and nodes crossed). Another five normal plants in each plot were harvested and used to determine biofuel traits (juice yield, ºbrix score and biomass). In the third experiment, a subset of entries evaluated in experiment II and three tolerant and susceptible checks were tested for greenbug feeding damage. Biotype K greenbug colony was inoculated to each genotype using double sticky foam cages. Feeding damage was assessed as percent chlorophyll loss using SPAD meter. There was significant general combining ability (GCA) effect among the male entries for juice yield, stem obrix and biomass production indicating that these traits are controlled by additive genes. Lines PI257602 and PI185672 in particular, had the highest GCA for all the traits and should serve as excellent breeding materials. There was no significant difference among the bmr mutants and between the bmr and normal genotypes for both stalk rot and greenbug damage. In conclusion, juice yield, °brix and biomass are largely controlled by additive genes and hence are amenable to genetic manipulation. The bmr mutations despite their impact on lignin content do not increase risk of attack by stalk rot pathogens and greenbugs and thus can be deployed for biofuel production without incurring losses to these factors.

Development of maize, Zea mays L., germplasm resistant to the European corn borer, Ostrinia nubilalis (Hubner) and Fusarium fungal pests has been in progress for more than three decades as a worldwide cooperative effort. Some of the host plant resistance to the European corn borer and Fusarium has been attributed to the phytochemical product 6-methoxybenzoxazolinone. However, it has been shown that seasonal weather impacts concurrently on maize development, corn borer and Fusarium phenology. It was hypothesized that some of the maize resistance to both pests depended directly on climatological conditions. In the United States, genotype selection for first generation borer resistance is achieved during June infestations using leaf feeding assessment. In Canada, first selection began at the silk stage of plant development in July. The second genotype selection is conducted at grain harvest in October by plant dissections. The larval population, number of tunnels and tunnel length in the first 30 cm of the stalk above the soil surface were used to differentiate genotype susceptibility to corn borers. Grain moisture was directly correlated with genotype resistance to corn borer. Fungi encountered comprised Fusarium moniliforme, F. graminearum, F. sporotrichioides, F. oxysporum, F. avenaceum, and F. equiseti. Two species, F. moniliforme and F. equiseti, were recovered throughout the season. These fungi were first recovered from pollen caught in the leaf collar sheath. As the leaf sheath of maize is relaxed with plant development, the Fusarium contaminated soil and the pollen run down past the ligule by wind, rain splash, and insect movement to settle within the sheath cavity. Undamage pith samples (by the borer) taken at grain harvest showed sporadic tissue contamination by Fusarium. Oppositely, as the corn borer larvae migrated downward on the plant, they drilled the collar sheath, the stalk rind and dug galleries in the stalk to feed on the pith tissue to complete their development. Consequently, the larvae and borer tunnels were repeatedly contaminated with Fusarium. It was shown that pith tissues were initially colonized by primary fungi such as F. equiseti which initiate pith breakdown; then these fungi were overgrown by more competitive species such as F. moniliforme or F. sporotrichioides. Correlation of the stalk rot incidence to genotype maturity and the stalk rot incidence to grain moisture were both negative and significant; indicating that physiological activity during October protected the stalk against fungi infection. It was hypothesized that genotype maturity based on the heat unit rating (given by companies) or grain moisture at harvest (indicator of genotype maturity) were the two common factors related to Fusarium stalk rot resistance. (Abstract shortened by UMI.)

Made available in DSpace on 2014-06-11T19:35:00Z (GMT). No. of bitstreams: 0 Previous issue date: 2004-12-16Bitstream added on 2014-06-13T20:45:44Z : No. of bitstreams: 1 fortes_nlp_dr_botfca.pdf: 629205 bytes, checksum: 40d1e91cf18ab3678f66c246588008c7 (MD5)<br>Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)<br>Universidade Estadual Paulista (UNESP)<br>O trabalho objetivou verificar os fatores químicos e microbiológicos do lodo de esgoto e do solo responsáveis pela incidência da podridão do colmo do milho, causada por Fusarium em solo fertilizado com lodo, e foi desenvolvido em condições de campo, numa área que vem sendo tratada com lodo e cultivada com milho desde 1999 em latossolo vermelho distróférrico (textura argilosa), localizada no município de Jaguariúna/SP. Os dois lodos utilizados foram obtidos nas Estações de Tratamento de Esgoto de Franca e de Barueri/SP. Os lodos foram incorporados ao solo nas concentrações de 0, 1, 2, 4 e 8 vezes a dose recomendada com base no teor de nitrogênio, em dois cultivos sucessivos de milho (Savana 133S) nas safras 2001/2002 e 2002/2003, em parcelas de 200 m2. As doses de lodo foram comparadas com a adubação mineral recomendada para a cultura do milho. Os tratamentos foram distribuídos em delineamento experimental casualizado em blocos e com três repetições. Foram verificadas, nas safras de 2001/2002 e 2002/2003, diferenças significativas entre as doses de lodo de esgoto, sobre a variação de Fusarium spp. no solo, na rizosfera, na raiz, no colmo e na semente, bem como sobre a incidência de plantas com podridão no colmo e nas espigas. As análises de regressão mostraram que a porcentagem de plantas doentes foi positivamente correlacionada com a concentração dos lodos incorporados ao solo. Os coeficientes de determinação para o cultivo de 2001/2002 foram de R2=0,61 e R2=0,32, enquanto para o cultivo de 2002/2003 foram de R2=0,76 e R2=0,45, para os lodos de Franca e Barueri, respectivamente. As concentrações de lodos também apresentaram correlação positiva com a comunidade de Fusarium do solo e da rizosfera e com a incidência de Fusarium na raiz, no colmo e na semente. As correlações entre a comunidade de Fusarium do solo e da rizosfera e o percentual de plantas... .<br>This work aimed at verifying the chemical and microbiological sewage sludge and soil factors re 0sponsible for the incidence of the corn stalk rot caused by Fusarium in soil fertilized with sludge and has been developed in field conditions, in an area that has been treated with sludge and cultivated with corn since 1999, in red dystroferric latosol (clayey texture), in Jaguariúna/SP. Both sludges used were obtained in the sewage sludge treatment stations of Franca and Barueri/SP. Sludges were incorporated into the soil in concentrations of 0, 1, 2, 4 and 8 times in relation to the recommended rate based on the nitrogen contents, in two successive corn cultures (Savana 133S), in 2001/2002 and 2002/2003, in plots of 200 m2. Sludge doses were compared to the mineral fertilization recommended to the corn culture. The treatments were distributed in a randomized design experimental drawing in blocks and with three repetitions. Significant differences were verified in both 2001/2002 and the 2002/2003 crops among the sewage sludge doses about the variation of Fusarium spp. in soil, root, stalk and seed, as well as about the incidence of plants with stalk and corn rot. The regression analyses have showed that the percentage of diseased plants was positively correlated to the concentration of the sludges incorporated to the soil. The determination coefficients to the 2001/2002 culture were R2=0.61 and R2=0.32, while the 2001/2003 culture showed R2=0.76 and R2=0.45, to Franca and Barueri sludges, respectively. The sludges concentrations also presented positive correlation with the Fusarium community of the soil and the rhizosphere, and with the incidence of Fusarium in the root, stalk and seed. The correlations between the Fusarium community of the soil and rhizosphere and the percentage of diseased plants with chemical soil attributes were significant and positive, for both kinds of sludges, in the level of 1 and 5%, to phosphorus and calcium contents.

O gênero Fusarium é um grupo de fungos de importância mundial, não só por causar patologias em plantas, mas também porque abriga espécies toxigênicas. Dentre estas, Fusarium verticillioides, Fusarium proliferatum e Fusarium subglutinans, cujos teleomorfos se agrupam no complexo Gibberella fujikuroi, estão associadas a patologias em milho. O presente estudo caracterizou uma coleção de 100 isolados de Fusarium spp. tanto do ponto de vista morfológico como molecular com vistas a identificá-los em nível de espécie. Para isto, foram usados como marcadores morfológicos a presença/ausência de clamidósporos, o tipo de célula conidiogênica e a disposição dos microconídios sobre a célula conidiogênica. Os isolados foram também identificados em espécie baseado em informações disponíveis na literatura acerca de marcadores moleculares desenvolvidos a partir da reação de PCR e primers espécie-específicos. A ausência de clamidósporo permitiu alocar a totalidade dos isolados no complexo G. fujikuroi. Os demais critérios morfológicos permitiram identificar 77 isolados como F. verticillioides, 20 como F. proliferatum, 2 como F. subglutinans. Apenas 1 isolado não foi possível identificar em espécie. Análises moleculares concordaram em 100% dos casos em que os isolados foram identificados como F. verticillioides e F. subglutinans. Porem, no caso dos 20 isolados identificados morfologicamente como F. proliferatum apenas 4 foram confirmados na análise molecular; os demais foram identificados como F. verticillioides. A diversidade genética estudada por AFLP ratificou a separação das espécies F. verticillioides e F. proliferatum, com um índice de similaridade de 0,40. Marcadores AFLP também evidenciaram alta diversidade genética de F. verticillioides. Todos os isolados causaram podridão do colmo em três híbridos comerciais de milho e não variaram em agressividade, independente do nível de resistência dos híbridos.<br>The genus Fusarium is an important group of fungi worldwide, not only for its capability to cause disease but because it also contains species which produce toxins. Among these, Fusarium verticillioides, Fusarium proliferatum and Fusarium subglutinans, which teleomorphs are grouped in the Gibberella fujikuroi group are associated with diseases in maize. This study characterized a collection of 100 isolates of Fusarium spp. under morphological and molecular criteria to identify them at the species level. For this purpose, morphological markers such as presence/absence of chlamydospores, conidiogenou cell type and microconidia arrangement on conidiogenou cell were assessed. The isolates were also identified at the species level based upon available information about molecular markers developed from the PCR reaction using speciesspecific primers. The absence of chlamydospores in all of the isolates placed them within the G. fujikuroi complex, and based on the other morphological criteria, 77 isolates were identified as F. verticillioides, 20 as F. proliferatum, 2 as F. subglutinans and one isolate remained unidentified at the species level. The molecular analyses agreed with the morphological identification of all F. verticillioides and F. subglutinans. However, in the case of 20 isolates identified morphologically as F. proliferatum only 4 were confirmed, the rest being identified as F. verticillioides. The genetic diversity based on AFLP confirmed the separation of F. verticillioides and F. proliferatum in two groups, with a similarity index of 0.40. AFLP markers also showed high genetic diversity within F. verticillioides. All isolates were caused stalk rot on three commercial hybrids and did not vary in aggressiveness regardless of the resistance level of the hybrids.

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior<br>The expansion of area under maize (Zea mays L.), and the use of no-till without a proper crop rotation have increased the incidence of stalk rot on this crop, due to the survival of this disease-causing pathogens (Fusarium spp., Diplodia spp., Colletotrichum graminicola, among others) in soil and crop residues. Fertilization has shown positive effect on the crop, but little is known about its relation to these pathogens and the organisms that control them. The objective of this study was to evaluate the effect of short and long-term of organic and mineral fertilizers and the effect of treatment of corn seeds with Trichoderma spp. Persson on the population of total fungi, Fusarium spp., and Trichoderma spp. in the soil and the production of dry matter (DM), accumulation of nitrogen (N), phosphorus (P) and potassium (K) in the tissue and grains, the incidence of stalk rot and corn yield. The experiment was conducted at the experimental area of the Soils Department, Federal University of Santa Maria, which has a history of six years application of organic and mineral fertilizers, and consisted in a factorial 5 (fertilization treatments) X 2 (seeds treatment) with split-plot in strips, using the randomized block design. The fertilization treatments (pig slurry; swine deep bedding; cattle slurry; mineral fertilizer; control treatment) were applied to the plots and the seeds treatment (with and without Trichoderma spp.) in the subplots (strips). It was used the hybrid Pioneer ® 30F53 Y, with 45 cm row spacing and final population of 78,000 plants per hectare. Soil samples were collected before application of treatments, for chemical analysis, and before and after, to characterize the soil fungal population. In the laboratory, dilution of samples and quantification of the fungi present was performed. At the flowering stage, three corn plants per subplot were collected for the assessment of DM production and nutrient accumulation in the tissue. At physiological maturity stage, the incidence of stalk rot was assessed, and the ears of corn harvested for productivity assessment. Nutrient content in corn kernels was also determined. The organic fertilizers pig slurry and swine deep bedding, in the long-term, increased population of Fusarium spp. in the soil. The organic and mineral fertilizers increased the production of DM and productivity of corn. Trichoderma spp. increased the production of DM of corn, but had no reflection on productivity. Both factors increased the incidence of stalk rot in corn. The swine deep bedding and cattle slurry increased the content of P and K in the tissue of corn plants. It is concluded that: the organic fertilizers can be used to increase the production of DM and productivity of corn and; Trichoderma spp. can be used if the objective is greater DM production.<br>A expansão da área cultivada com milho (Zea mays L.) e a utilização do plantio direto sem uma rotação de culturas adequada têm aumentado a incidência de podridões de colmo nessa cultura, devido à sobrevivência dos patógenos causadores da doença (Fusarium spp., Diplodia spp., Colletotrichum graminicola, entre outros) no solo e em restos culturais. A adubação tem apresentado efeitos positivos sobre a cultura, mas pouco se sabe sobre sua relação com esses patógenos e os organismos que promovem seu controle. O objetivo do presente trabalho foi avaliar o efeito a curto e longo prazos da adubação orgânica e o efeito do tratamento de sementes de milho com Trichoderma spp. sobre a população de fungos totais, Fusarium spp. e Trichoderma spp. no solo e a produção de matéria seca (MS), acúmulo de nitrogênio (N), fósforo (P) e potássio (K) no tecido e nos grãos, a incidência de podridões de colmo e a produtividade de milho. O experimento foi conduzido na área experimental do Departamento de Solos da Universidade Federal de Santa Maria, que possui histórico de seis anos de aplicação de adubos orgânicos e mineral, e constituiu-se em um fatorial 5 (tratamentos de adubação) X 2 (tratamento das sementes), com parcelas subdivididas em faixas, sendo utilizado o delineamento blocos casualizados. Os tratamentos de adubação (dejeto líquido de suínos; cama sobreposta de suínos; dejeto líquido de bovinos; adubação mineral; tratamento testemunha) foram aplicados nas parcelas e o tratamento das sementes (com e sem Trichoderma spp.) nas subparcelas (faixas). Foi utilizado o híbrido 30F53 Y, da empresa Pioneer®, espaçamento entre linhas de 45 cm e população final de 78000 plantas por hectare. Amostras de solo foram coletadas antes, para análise química, e antes e após a aplicação dos tratamentos para caracterização da população fúngica do solo. Em laboratório, foi realizada a diluição serial das amostras e quantificação dos fungos presentes. No estádio de florescimento foram coletadas três plantas de milho por subparcela para a avaliação da produção de matéria seca e acúmulo de nutrientes no tecido. No estádio de maturação fisiológica, foram realizadas a avaliação da incidência de podridões de colmo e a colheita das espigas para o cálculo da produtividade. Também foi determinado o teor de nutrientes nos grãos de milho. Os adubos orgânicos dejeto líquido de suínos e cama sobreposta de suínos, em longo prazo, aumentaram a população de Fusarium spp. no solo. Os adubos orgânicos e mineral aumentaram a produção de MS e a produtividade de milho. Trichoderma spp. aumentou a produção de MS de milho, porém não teve reflexo sobre a produtividade. Os adubos orgânicos aumentaram a incidência de podridões de colmo no milho. A cama sobreposta de suínos e o dejeto líquido de bovinos aumentaram o teor de P e K no tecido das plantas de milho. Conclui-se que: os adubos orgânicos podem ser utilizados para aumentar a produção de MS e a produtividade de milho e; Trichoderma spp. pode ser utilizado quando se objetiva maior produção de MS.

Made available in DSpace on 2016-12-08T16:44:47Z (GMT). No. of bitstreams: 1 PGPV13MA146.pdf: 1025870 bytes, checksum: 3db0ad6dd00a768dbc759ef22dc655a4 (MD5) Previous issue date: 2013-12-03<br>To gain a better understanding of the importance of corn stalk rot in grain yield and quality a field and laboratory experiments were conducted in order to accomplish the following objectives a) evaluate the stalk rot (SR) incidence and its effect on grain yield in eight corn hybrids cultivated under no-till system with soybean rotation and oats succession, in three locations of Campos de Cima da Serra, Rio Grande do Sul State; and b) assess the accuracy and precision between observers when analyzing corn kernel rot (KR) samples. In a field experiment conducted in 2012/13 growing season at three locations (Ipê, Vacaria and Muitos Capões), the following hybrids 2A550 Hx, AS 1555 PRO 2, AS 1656 PRO 2, DKB 330 PRO 2, P1630 Hx, P30F53 Hx, Hx P30R50 and Status Viptera were evaluated for stalk rot and grain yield. The experiment was designed in a randomized complete block with four replications. The incidence of SR was determined about 25 days after the grains reached the physiological maturity. Potential and real yield were determined by separately collecting the ears from healthy (stalk rot symptomless) and diseased plants (showing stalk rot symptoms). Means comparison analysis was performed by the Scott-Knott method (P<0.05). Overall anthracnose was the predominant disease in all locations. The average incidence of SR in Ipê, Vacaria and Muitos Capões was 42.55%, 42.6% and 39.25%, respectively. The yield ranged from 4,623 kg ha-1 and 5,954 kg ha-1 in Ipê, 4,252 kg ha-1 and 5,676 kg ha-1 in Vacaria and 4,594 kg ha-1 to 6,574 kg ha-1 in Muitos Capões. In the combined analysis, hybrids with higher yield were AS 1656 PRO2 (5,800 kg ha-1), AS 1555 PRO2 (5,765 kg ha-1), P1630 HX (5,351 kg ha-1) and P30F53 (5,332 kg ha-1). The average damage in yield of hybrids was 12.79%, ranging from 563 kg ha-1 to 1,073 kg ha-1, with an average of 761.25 kg ha-1. The laboratory experiments were conducted at the Plant Pathology Laboratory at Universidade do Estado de Santa Catarina in 2013. To assess the accuracy and precision between observers when analyzing corn kernel rot (KR), samples with 1 kg of corn grain were divided in 250 g and 15 undergrads and grad students estimated the KR percentage of each sample. Afterwards six samples with 250 g of corn grains containing 0%, 1%, 2%, 6%, 12% and 18% incidence of KR were submitted to the same observers. Analysis of the incidence of kernel rot was performed by mean and standard deviation of the percentage difference between the estimated evaluators with the actual value for each class value. In the first experiment, the average KR detected by the evaluators was 43.19%, ranging from 24.89% to 61.05% and standard deviation 10.68. In the samples containing 0%, 1% and 2% of KR, it was observed that all evaluators overestimated incidence, the average being detected in each class of 0.96%, 2.13% and 4.13%, respectively. Classes of 6%, 12% and 18% of KR observed a smaller difference between estimates, with the quantification of evaluators of 7.77%, 12.6% and 17.7%, respectively. With the increasing incidence of KR, the average percentage between estimates and actual value decreased from 113% to 2% for classes 1% and 18%, with a standard deviation of 108,81 and 1,64, respectively<br>Na escolha do cultivar de milho faz-se necessário o conhecimento do rendimento, qualidade de grãos e danos causados por fitopatógenos presentes na região de cultivo. Os objetivos deste trabalho foram: a) avaliar a incidência de podridões do colmo (PC) e seu efeito no rendimento de grãos em oito híbridos de milho, cultivados em sistema de semeadura direta com rotação à soja e sucessão à aveia, em três municípios na Região de Campos de Cima da Serra, estado do Rio Grande do Sul; b) determinar a acurácia e precisão entre observadores ao analisarem amostras de milho contendo diferentes incidências de grão ardido (GA). No Capítulo I, em experimentos conduzidos no campo, nos municípios de Ipê, Vacaria e Muitos Capões, safra 2012/13, foram avaliados os híbridos 2A550Hx, AS 1555 PRO2, AS 1656 PRO2, DKB 330 PRO2, P1630Hx, P30F53Hx, P30R50Hx e Status viptera. O delineamento foi de blocos casualisados com quatro repetições. A incidência de PC foi quantificada aproximadamente 25 dias após a maturação fisiológica dos grãos. O rendimento de grãos foi determinado coletando-se separadamente as espigas das plantas sadias e doentes para obtenção do cálculo de rendimento e dano causado por PC. Efetuou-se a comparação das médias por meio do teste Scott-Knott, em nível de significância de 5% (P<0,05). Em todos os locais a doença predominante foi antracnose. A incidência média de PC em Ipê, Vacaria e Muitos Capões foi 42,5%, 42,6% e 39,2%, respectivamente. O rendimento oscilou de 4.623 kg ha-1 a 5.954 kg ha-1 em Ipê, 4.252 kg ha-1 a 5.676 kg ha-1 em Vacaria e 4.594 kg ha-1 a 6.574 kg ha-1 em Muitos Capões. Na análise conjunta os híbridos com maior rendimento foram AS 1656 PRO2 (5.800 kg ha-1), AS 1555 PRO2 (5.765 kg ha-1), P1630 HX (5.351 kg ha-1) e P30F53 (5.332 kg ha-1). O dano médio no rendimento dos híbridos foi de 12,79%, variando de 563 kg ha-1, até 1.073 kg ha-1, com média de 761,25 kg ha-1. No Capítulo II, os experimentos foram conduzidos no ano de 2013 no Laboratório de Fitopatologia da Universidade do Estado de Santa Catarina. O primeiro experimento foi realizado com amostra de 1 kg de grãos de milho, quarteada em 250 g e repassada para 15 alunos de graduação e pós-graduação, para análise da incidência de GA. No segundo experimento, seis amostras com 250 g de grãos de milho contendo 0%, 1%, 2%, 6%, 12% e 18% de grãos avariados foram submetidas aos mesmos observadores. A análise da incidência de GA foi realizada pela média e desvio padrão da diferença percentual do valor estimado entre avaliadores com o valor real para cada classe. No primeiro experimento, a média detectada de GA pelos avaliadores foi de 43,19%, com variação de 24,89% a 61,05% e desvio padrão 10,68. Nas amostras contendo 0%, 1% e 2% de GA, observou-se que todos os avaliadores superestimaram a incidência, sendo a média detectada em cada classe de 0,96%, 2,13% e 4,13%, respectivamente. Nas classes de 6%, 12% e 18% de GA observou-se menor diferença entre estimativas, com média da quantificação dos avaliadores de 7,77%, 12,6% e 17,7%, respectivamente. Com o incremento da incidência de grãos ardidos o percentual médio entre estimativas e valor real decresceu de 113% até 2% para classes de 1% e 18%, com desvio padrão de 108,81 e 1,64, respectivamente

Orientador : Raquel Ghini<br>Banca: Raquel Ghini<br>Banca: Wagner Bettiol<br>Banca: Nilton Luiz de Souza<br>Banca: Idalmir dos Santos<br>Banca: Gisela Maria Fantin<br>Resumo: O trabalho objetivou verificar os fatores químicos e microbiológicos do lodo de esgoto e do solo responsáveis pela incidência da podridão do colmo do milho, causada por Fusarium em solo fertilizado com lodo, e foi desenvolvido em condições de campo, numa área que vem sendo tratada com lodo e cultivada com milho desde 1999 em latossolo vermelho distróférrico (textura argilosa), localizada no município de Jaguariúna/SP. Os dois lodos utilizados foram obtidos nas Estações de Tratamento de Esgoto de Franca e de Barueri/SP. Os lodos foram incorporados ao solo nas concentrações de 0, 1, 2, 4 e 8 vezes a dose recomendada com base no teor de nitrogênio, em dois cultivos sucessivos de milho (Savana 133S) nas safras 2001/2002 e 2002/2003, em parcelas de 200 m2. As doses de lodo foram comparadas com a adubação mineral recomendada para a cultura do milho. Os tratamentos foram distribuídos em delineamento experimental casualizado em blocos e com três repetições. Foram verificadas, nas safras de 2001/2002 e 2002/2003, diferenças significativas entre as doses de lodo de esgoto, sobre a variação de Fusarium spp. no solo, na rizosfera, na raiz, no colmo e na semente, bem como sobre a incidência de plantas com podridão no colmo e nas espigas. As análises de regressão mostraram que a porcentagem de plantas doentes foi positivamente correlacionada com a concentração dos lodos incorporados ao solo. Os coeficientes de determinação para o cultivo de 2001/2002 foram de R2=0,61 e R2=0,32, enquanto para o cultivo de 2002/2003 foram de R2=0,76 e R2=0,45, para os lodos de Franca e Barueri, respectivamente. As concentrações de lodos também apresentaram correlação positiva com a comunidade de Fusarium do solo e da rizosfera e com a incidência de Fusarium na raiz, no colmo e na semente. As correlações entre a comunidade de Fusarium do solo e da rizosfera e o percentual de plantas... (Resumo completo, clicar acesso eletrônico abaixo).<br>Abstract: This work aimed at verifying the chemical and microbiological sewage sludge and soil factors re 0sponsible for the incidence of the corn stalk rot caused by Fusarium in soil fertilized with sludge and has been developed in field conditions, in an area that has been treated with sludge and cultivated with corn since 1999, in red dystroferric latosol (clayey texture), in Jaguariúna/SP. Both sludges used were obtained in the sewage sludge treatment stations of Franca and Barueri/SP. Sludges were incorporated into the soil in concentrations of 0, 1, 2, 4 and 8 times in relation to the recommended rate based on the nitrogen contents, in two successive corn cultures (Savana 133S), in 2001/2002 and 2002/2003, in plots of 200 m2. Sludge doses were compared to the mineral fertilization recommended to the corn culture. The treatments were distributed in a randomized design experimental drawing in blocks and with three repetitions. Significant differences were verified in both 2001/2002 and the 2002/2003 crops among the sewage sludge doses about the variation of Fusarium spp. in soil, root, stalk and seed, as well as about the incidence of plants with stalk and corn rot. The regression analyses have showed that the percentage of diseased plants was positively correlated to the concentration of the sludges incorporated to the soil. The determination coefficients to the 2001/2002 culture were R2=0.61 and R2=0.32, while the 2001/2003 culture showed R2=0.76 and R2=0.45, to Franca and Barueri sludges, respectively. The sludges concentrations also presented positive correlation with the Fusarium community of the soil and the rhizosphere, and with the incidence of Fusarium in the root, stalk and seed. The correlations between the Fusarium community of the soil and rhizosphere and the percentage of diseased plants with chemical soil attributes were significant and positive, for both kinds of sludges, in the level of 1 and 5%, to phosphorus and calcium contents.<br>Doutor

This study evaluated the effect of Pratlenchus brachyurus and Fusarium verticillioides, and their relationship, on growth and development of two mayze hybrids (30F80 and 30K73). The experiment was conducted in greenhouse conditions at Pioneer Hi-bred Research Center in Itumbiara, GO, Brazil. The experimental design was randomized blocks with 15 treatments and 10 replications. Treatments included a non-inoculated control; inoculation of Fusarium in the seed and in the soil; three populations levels of Pratylenchus at sowing and at 30 days after planting (50, 100 and 500 nematodes/plot), with and without the inoculation of Fusarium in the soil; and three populations leves of Pratylenchus inoculated 30 days after sowing with Fusarium inoculated in seed at sowing. At plant maturity the following variables were evaluated: plant height and ear length, stalk diameter, root fresh and dry matter, stalk fresh and dry matter, reproduction factor and fusariosis severity on the stalk. Fusarium stalk colonization was evaluated in a scale from 1 to 9. The 30F80 hybrid had lower plant height and ear length, stalk diameter, stalk and root fresh matter when the seeds were inoculated with the suspension of Fusarium and sowing immediately after inoculation. The maize hybrids 30F80 and 30K73, showed the lowest root length, stalk fresh and dry matter, and root fresh and dry matter mainly when the soil was inoculated with Fusarium and sown in the same day, and the inoculation with 500 juveniles and/or adults of Pratylenchus, was done 30 days after sowing. The maize hybrid 30K73 obtained lower plant height and ear length when seeds were inoculated with the suspension of Fusarium and sown in the same day. Maize seeds inoculated with Fusarium verticillioides at planting decreased plant height, ear length, and root and shoot fresh weight on both hybrids. Stalk diameter of 30K73 hybrid and root length of hybrid 30K73 were also reduced. Soil inoculation of Fusarium verticillioides at planting and Pratylenchus brachyurus inoculated 30 days after planting (500 nematodes/plot) decreased root elongation and stalk, and root dry weights on both hybrids. However, plant height was only reduced on 30K73 hybrid. Future research is needed to better understand the relationship between Pratylenchus brachyurus and Fusarium verticillioides on maize growth and development.<br>O objetivo deste estudo foi avaliar o efeito de Pratylenchus brachyurus e/ou Fusarium verticillioides e sua relação no desenvolvimento de dois híbridos de milho (30F80 e 30K73). O experimento foi conduzido em casa de vegetação no Centro de Pesquisa da Pioneer Sementes de Itumbiara-GO. O delineamento experimental foi inteiramente ao acaso com 15 tratamentos/por híbrido (totalizando 30 tratamentos) e 10 repetições. Os tratamentos foram: testemunha (sem inoculações), inoculação de fungo nas sementes e no solo; inoculação de três populações de nematóide na semeadura e 30 dias após a semeadura (50, 100 e 500 nematóides/vaso), com e sem inoculação do fungo no solo; e três níveis populacionais de nematóides inoculados 30 dias após a semeadura, com o fungo inoculado na semente. Após a maturação (estádio R7), foram avaliadas as características: altura de planta e de espiga, diâmetro de colmo, matéria fresca e seca de raiz, matéria fresca e seca de colmo, fator de reprodução do nematóide e severidade de fusariose no colmo do milho. Observou-se que o híbrido de milho 30F80 obteve uma menor altura de planta e de espiga, diâmetro de colmo, matéria fresca de colmo e de raíz, quando as sementes foram inoculadas com a suspensão de conídios de Fusarium verticillioides e semeadura realizada no mesmo dia dessa inoculação. Os híbridos de milho 30F80 e 30K73 apresentaram o menor comprimento de raiz, matéria fresca e seca de colmo, e matéria fresca e seca de raiz, principalmente quando o solo foi inoculado com Fusarium verticillioides, semeou-se no mesmo dia e a inoculação do nematóide na população de 500 juvenis e/ou adultos de Pratylenchus brachyurus realizada 30 dias após a semeadura. O híbrido de milho 30K73 obteve uma menor altura de planta e de espiga quando as sementes foram inoculadas com a suspensão de conídios de Fusarium verticillioides e semeadura realizada no mesmo dia dessa inoculação. Sementes de milho inoculadas com o fungo na semeadura diminuiram a altura de planta e de espiga e peso fresco de raiz e de parte aérea nos dois híbridos de milho. Diâmetro de colmo no híbrido 30F80 e comprimento de raiz no híbrido 30K73 também foram reduzidos. A inoculação do solo com o fungo na semeadura e nematóide inoculado 30 dias após (500) proporcionou menor comprimento de raiz e peso seco e fresco de raiz e colmo nos dois híbridos. Contudo, altura de planta foi reduzida somente no híbrido 30K73. Outros estudos de interações entre microrganismos, em especial de Pratylenchus brachyurus e Fusarium verticilliodes, deverão ser realizados, a fim de melhor entender o efeito desta combinação no prejuízo das plantas.<br>Mestre em Agronomia

Made available in DSpace on 2016-12-08T16:44:41Z (GMT). No. of bitstreams: 1 PGPV12MA096.pdf: 1514987 bytes, checksum: c0706020e05a268de58f6c3e9ec12e0a (MD5) Previous issue date: 2012-08-21<br>Coordenação de Aperfeiçoamento de Pessoal de Nível Superior<br>Maize has low vegetative plasticity, because it normally does not tiller, it has limited capacity to expand the leaf blade and it does not alter the number of expanded leaves due to changes in environment or management. Therefore, damages in leaf area caused by defoliation can decrease grain yield and increase the occurrence of base stalk rots (BSR) and rot grains (RG), reducing grain quality. The cultivar`s genetic variability may interfere on the extension of damages caused by defoliation. This research was carried out aiming to quantify grain yield losses and the effect on base stalk rot (BSR) and rot grains (RG) caused by defoliation at different growth stages of maize cultivars with contrasting genetic variability. A field experiment was set in Lages-SC, during the growing seasons of 2010/11 and 2011/2012. Three cultivars were tested: the open pollinated variety (OPV) SCS 155 Catarina, the triple hybrid (TH) P30B30 and the single-cross hybrid (SC) P30R50H. Each cultivar was defoliated when plants had eight (V8), 12 (V12), 16 (V16) and 20 (V20) expanded leaves. A control treatment without defoliation was also assessed. The experiments were sown in the no-tillage system on 10/22/2010 and 10/19/2011. The plant density of 60,000 pl ha &#1471;1 and the row spacing of 0.7 m were used in the trial. Defoliations performed at V8 and V12 did not affect the SC and TH grain yield, but they decreased the OPV productivity. The defoliation performed at V20 reduced by more than 70% the grain yield of all cultivars. The removal of eight and 12 leaves did not increase the incidence of BSR and the percentage of broken plants in comparison to the control. Late defoliations performed at V16 V20 weakened the stalk, increasing the occurrence of BSR and broken plants for the three cultivars. The greater genetic variability of OPV SCS 155 Catarina was not efficient to minimize grain yield losses caused by defoliation, neither to decrease the incidence of base stalk rot nor rot grains, in comparison to the hybrids P30B30 and P30R50H<br>A cultura do milho possui baixa plasticidade vegetativa, pois normalmente não perfilha, apresenta limitada capacidade de expansão do limbo foliar e não altera o número de folhas expandidas devido a mudanças no ambiente ou no manejo. Os danos na área foliar ocasionados pela desfolha podem reduzir o rendimento de grãos e aumentar a ocorrência de podridões da base do colmo (PBC) e de grãos ardidos (GA), depreciando a qualidade dos grãos. A variabilidade genética da cultivar pode interferir na magnitude dos danos ocasionados pela desfolha. Esta pesquisa teve como objetivos quantificar os prejuízos no rendimento de grãos e a influência sobre PBC e GA, ocasionados pela desfolha imposta em diferentes estádios fenológicos em cultivares de milho com bases genéticas contrastantes. O experimento foi conduzido a campo, no município de Lages-SC, nos anos agrícolas de 2010/11 e 2011/12. Foram testadas três cultivares de milho: a variedade de polinização aberta (VPA) SCS 155 Catarina, o híbrido triplo (HT) P30B30 e o híbrido simples (HS) P30R50H. Cada cultivar foi desfolhada quando as plantas tinham oito (V8), 12 (V12), 16 (V16) e 20 (V20) folhas expandidas e foi mantida uma testemunha com folhas intactas. Os experimentos foram implantados no sistema de semeadura direta, em 22/10/2010 e 19/10/2011. A densidade utilizada foi de 60.000 plantas ha-1 e o espaçamento entre linhas de 0,7m. As desfolhas realizadas em V8 e V12 não comprometeram o rendimento de grãos do HS e do HT, mas reduziram o rendimento da VPA. A desfolha realizada em V20 reduziu em mais de 70% o rendimento de grãos das três cultivares. A remoção de oito e 12 folhas não aumentou a incidência de PBC e a percentagem de plantas quebradas, em relação à testemunha. As desfolhas mais tardias (V16 e V20) aumentaram a ocorrência de PBC e de plantas quebradas das três cultivares. A maior variabilidade genética da VPA SCS 155 Catarina não foi eficaz para minimizar as perdas ocasionadas pela desfolha no rendimento de grãos, nem tão pouco para diminuir a incidência de podridões da base do colmo e grãos ardidos, em comparação aos híbridos P30B30 e P30R50H

Submitted by Claudia Rocha (claudia.rocha@udesc.br) on 2018-02-21T14:08:34Z No. of bitstreams: 1 PGPV15MA187.pdf: 174820 bytes, checksum: ee57afc9c4d2a1b5e1435af1a2438825 (MD5)<br>Made available in DSpace on 2018-02-21T14:08:34Z (GMT). No. of bitstreams: 1 PGPV15MA187.pdf: 174820 bytes, checksum: ee57afc9c4d2a1b5e1435af1a2438825 (MD5) Previous issue date: 2015-02-27<br>Capes<br>The objective of this study was to evaluate the incidence and damage of stalk rot (SR) in corn hybrids grown in tillage rotation with beans and succession to oats; quantify the efficiency of detection and control of Fusarium verticillioides in seed and seedlings health test according to the time of incubation. The first study was carried out at Muitos Capões municipal district on Rio Grande do Sul State, during the agricultural seasons of 2012/13 and 2013/14.The hybrids tested were P30F53 Hx, P32R22 YHR, DKB 250 VTPRO2, AS1555 VTPRO2, AS 1656 VTPRO2, AG8025 VTPRO e AG 9045 VTPRO. A randomized block design with four replications was employed. The incidence of SR was determined during harvesting and the damage by threshing operation analyzed separately in healthy and unhealthy plants. The means were compared by Scott-Knott test with a significance level of 5% (P <0.05). Statistical interaction between corn hybrid and harvesting season was detected. For this reason, the data was analyzed by harvesting season. In the 2012/13 growing season the prevailing diseases were diplodia blight, Anthracnosis and Fusarium, and as opposed to 2013/14, when Gibberella, Diplodia blight and Fusarium wilting were the prevailing in 2013/14. The incidence of SR in 2012/13 and 2013/14 ranged from 7.3% to 100% (46.2% in average), and from 3.14% to 72.6% (34.8% in average). The average of damage in the yield of hybrids were 6,48% and 8,75%, ranging from 197 kg ha-1 to 1205 kg ha-1 and from 113 kg ha-1 to 2536 kg ha-1, with an average of 640 kg ha-1 and 768 kg ha-1, respectively in 2012/2013 and 2013/14. In both growing seasons the hybrids P32R22 YHR and AG9045 VTPRO showed the highest SR incidence. The lowest incidence of this disease was detected in the P30F53 Hx and AG8025 VTPRO hybrids in 2012/13 and AG8025 VTPRO and DKB 250 VTPRO2 in 2013/14. The highest damages were found in AS1555 VTPRO2 (14%) and AG9045 VTPRO (11.2%) in 2012/13, and AG9045 VTPRO (26.3%) in 2013/14. The yield ranged from 8.430 kg ha-1 to 10.667 kg ha-1 in 2012/13 and 7.175 kg ha-1 and 8.790 kg ha-1 in the 2013/14. Secondly, hybrid corn seeds Status TL TG treated with metalaxyl-m + fludioxonil fungicides and seeds without seed treatment were cultured in PDA Culture Media to obtain symptomatic seedlings (infected by F. verticullioides) and asymptomatic, with 7 days of age. The samples were separated and transferred to test tubes containing agar-water culture media and maintained in growth chamber at 25 °C under 12 hours of photoperiod until the completion of 20 days. The treatments were T1 - uninfected seedlings without TS; T2 - infected seedlings without TS; T3 - uninfected seedlings with TS; T4 - infected seedlings with TS. The fungus incidence was quantified in the mesocotyl, crown and remaining seed and shoot and root length and dry matter weight were measured. Randomized block experimental design with eight replications was used. The data was submitted to variance analysis and Tukey’s test at 5% of significance level. The incidence of F. verticillioides in the remaining seeds was 96% for T1 and T3, and 100% for T2 and T4, with no difference between treatments. The incidence of F. verticillioides was 88% and 93% for mesocotyl, and 88% and 95% in the crown in the T1 and T3 seedlings, respectively. The root length showed 14.1 cm and 10.7 cm for T3 and T4 respectively, which are higher than T1 (9.6 cm) and T2 (5.8 cm). Higher root weight was detected in T3 (0.25 g) and T4 (0.18 g) cultivars compared to T1 (0.12 g) and T2 (0.09 g). T3 showed the highest shoot length (14.2 cm) when compared to the other treatments. The corn seed treatment with metalaxyl-m + fludioxonil fungicides is not effective in controlling F. verticillioides. The detection of F. verticillioides in BDA media at the seventh day of incubation does not represent the real incidence of the fungus, once the pathogen was recovered from asymptomatic seedlings when they were re-evaluated at 20 days. In all treatments, the seed treatment enhanced the seedlings development<br>Os objetivos deste trabalho foram avaliar a incidência e os danos causados por podridões do colmo (PC) em híbridos de milho cultivados em sistema de semeadura direta com rotação ao feijão e sucessão à aveia; e quantificar a eficiência de detecção e controle de Fusarium verticillioides em meio batata-dextrose-ágar em sementes e plântulas de milho em função do tempo de incubação. Foram realizados dois estudos, sendo estes conduzidos no município de Muitos Capões, estado do Rio Grande do Sul, nas safras agrícolas 2012/13 e 2013/14. Foram avaliados os híbridos P30F53 Hx, P32R22 YHR, DKB250 VTPRO2, AS1555 VTPRO2, AS1656 VTPRO2, AG8025 VTPRO e AG9045 VTPRO. O delineamento experimental foi de blocos casualizados com quatro repetições. A incidência de PC foi determinada na colheita do milho, sendo o dano mensurado pela trilha em separado de espigas das plantas sadias e plantas doentes. A comparação das médias foi realizada pelo teste de Scott-Knott, em nível de significância de 5% (p<0,05). Houve interação entre híbridos e safras, sendo os dados analisados separadamente por safra. Em 2012/13, as doenças predominantes foram diplodia, antracnose e fusariose; em 2013/14, houve predomínio de giberela, diplodia e fusariose. A incidência de PC em 2012/13 e 2013/14 variou de 7,3% a 100% (média de 46,2%) e de 3,14% a 72,6% (média de 34,8%), respectivamente. O dano médio no rendimento de grãos dos híbridos foi de 6,8% e 8,7%, respectivamente para 2012/13 e 2013/14. Nas duas safras os híbridos P32R22 YHR e AG9045 VTPRO apresentaram maior incidência de PC. As menores incidências foram detectadas nos híbridos P30F53 Hx e AG8025 VTPRO na safra de 2012/13, e AG8025 VTPRO e DKB250 VTPRO2 na safra de 2013/14. Os maiores danos foram encontrados nos híbridos AS1555 VTPRO2 (14%) e AG9045 VTPRO (11,2%) em 2012/13, e AG9045 VTPRO (26,3%) em 2013/14. No segundo estudo, sementes de milho tratadas com fungicida metalaxil-m + fludioxonil e sem tratamento foram semeadas em meio de cultura de batata-dextrose-ágar para obtenção de plântulas sintomáticas (infectadas por F. verticillioides) e assintomáticas. Aos sete dias as plântulas foram separadas e transferidas para tubos de ensaio contendo meio de cultura ágar-água e mantidas em câmara de crescimento com temperatura de 25ºC e fotoperíodo de 12 h, onde permaneceram até completarem 20 dias. Obtiveram-se os tratamentos: T1 - plântulas assintomáticas sem fungicida; T2 - plântulas sintomáticas sem fungicida; T3 – plântulas assintomáticas com fungicida; T4 – plântulas sintomáticas com fungicida. A incidência foi quantificada no mesocótilo, coroa e semente remanescente das plântulas e o comprimento e peso seco da parte aérea e raiz. Os dados foram submetidos à análise de variância e teste de Tukey a 5%. A incidência de F. verticillioides em sementes remanescentes foi de 96% para T1 e T3, e 100% para T2 e T4, não diferindo os tratamentos entre si. Foi observada incidência de F. verticillioides de 88 e 93 % para mesocótilo, e 88 e 95% para coroa em plântulas provenientes de T1 e T3, respectivamente. O comprimento de raiz foi de 14,1 cm e 10,7 cm para T3 e T4 respectivamente, sendo estes superiores ao T1 (9,6 cm) e T2 (5,8 cm). Foram detectados maiores pesos de raiz nos tratamentos T3 (0,25 g) e T4 (0,18 g), quando comparados a T1 (0,12 g) e T2 (0,09 g). O T3 apresentou o maior comprimento de parte aérea,14,2 cm, em relação aos demais tratamentos. O tratamento de sementes com metalaxil-m + fludioxonil não foi eficiente no controle de F. verticillioides. A detecção de F. verticillioides em meio BDA aos sete dias de incubação não representou a real incidência do fungo, pois o patógeno foi recuperado de plântulas até então assintomáticas quando essas foram reavaliadas aos 20 dias. De qualquer forma o tratamento proporcionou maior comprimento e peso de raiz e parte área em plântulas de milho

Software is still being produced and used that is vulnerable to exploitation. As well as being in devices in the homes of many people around the world, programs with these vulnerabilities are maintaining life-critical systems such as power-stations, aircraft and medical devices and are managing the creation and distribution of billions of pounds every year. These systems are actively being exploited by governments, criminals and opportunists and have led to loss of life and a loss of wealth. This dependence on software that is vulnerable to exploitation has led to a society with tangible concerns over cyber-crime, cyber-terrorism and cyber-warfare. As well as attempts to eliminate these vulnerabilities, techniques have been developed to mitigate their effects; these prophylactic techniques do not eliminate the vulnerabilities but make them harder to exploit. As software exploitation is an ever evolving battle between the attackers and the defenders, identifying methods to bypass these mitigations has become a new battlefield in this struggle and the techniques that are used to do this require vulnerabilities of their own. As many of the mitigation techniques are dependent upon secrecy of one form or another, vulnerabilities which allow an attacker to view those secrets are now of importance to attackers and defenders. Leaking of the contents of computer memory has always been considered a vulnerability, but until recently it has not typically been considered a serious one. As this can be used to bypass key mitigation techniques, these vulnerabilities are now considered critical to preventing whole classes of software exploitation. This thesis is about detecting these types of leaks and the information they disclose. It discusses the importance of these disclosures, both currently and in the future. It then introduces the first published technique to be able to reliably identify specific classes of these leaks, particularly address disclosures and canary-disclosures. The technique is tested against a series of applications, across multiple operating systems, using both artificial examples and software that is critical, commonplace and complex.

O objetivo deste trabalho foi avaliar a distribuição espacial de adultos e ninfas da cigarrinha-das-raízes da cana-de-açúcar, Mahanarva fimbriolata (Stål., 1854) (Hemiptera: Cercopidae), a eficiência do sistema de amostragem atualmente empregado em escala comercial, a possibilidade de estimar a população de ninfas por meio da contagem de espumas e, a partir desses resultados, estabelecer um plano de amostragem confiável, prático e de baixo custo para utilização em programas de manejo integrado desta praga. A determinação da distribuição espacial foi feita em Ourinhos e Guariba-SP, demarcando-se três parcelas de 1,1 ha, em talhão colhido mecanicamente sem a queima da palha e com histórico de ataque da cigarrinha-dasraízes. As avaliações foram feitas em três épocas diferentes, contando-se o número de adultos e ninfas na base das touceiras, em 50% da área da parcela. Os adultos e ninfas de M. fimbriolata distribuem-se de forma agregada ou contagiosa na cultura da cana-de-açúcar e este padrão de distribuição não se altera ao longo das gerações, nem é influenciado pelo nível de infestação ou variedade cultivada. Utilizando-se os dados obtidos nestes experimentos calculou-se, para cada local e época de amostragem, o índice de dispersão k e o número de amostras necessárias para estimar a população de ninfas, considerando-se diferentes níveis de precisão, e realizaram-se simulações para diferentes tamanhos de amostra e esquemas de caminhamento. O plano de amostragem mais adequado para avaliação da população da cigarrinha-das-raízes em cana-de-açúcar foi determinado por meio do intervalo de confiança da média (P &#8804; 0,05) para a Variação Relativa (VR) e Precisão Relativa (PR). Os melhores resultados foram obtidos com 18 amostras de 1 metro linear por hectare, distribuídas na área de forma sistemática. Para a avaliação do método de amostragem comercial, instalaram-se dois experimentos em Ourinhos, demarcando-se duas parcelas de 1,1 ha, nas mesmas condições anteriores. Quinzenalmente, quantificou-se o número de formas biológicas em 300 pontos de 1m linear na parcela (amostragem experimental) e no restante da área do talhão (amostragem comercial), em 4 pontos de dois sulcos de 2m lineares/ha. Comparando-se os dados por meio de uma análise de regressão linear verificou-se que o método de amostragem comercial apresentou boa precisão na estimativa da população de ninfas, porém foi pouco preciso para adultos. Sua acurácia foi baixa para ninfas e adultos, subestimando as populações reais. A relação entre as contagens de espumas e ninfas nas amostragens comercial e experimental foi avaliada por meio de uma análise de regressão linear, observando-se alta correlação entre estes parâmetros, com coeficientes de determinação superiores a 0,96. Os resultados obtidos indicam que, independentemente da época de avaliação e do nível de infestação, é possível estimar a população de ninfas da cigarrinha-dasraízes em cana-de-açúcar por meio da contagem de espumas, com elevado grau de confiabilidade.<br>The objective of this research was to evaluate the spatial distribution of adults and nymphs of the sugarcane root froghopper, Mahanarva fimbriolata (Stal, 1854) (Hemiptera: Cercopidae), to evaluate the efficiency of the sampling system presently used to monitor the populations in commercial fields, and to estimate nymph populations by counting foam spots. The results obtained in this work were used to establish a low cost and reliable sampling method in order to improve the integrated pest management program for the sugarcane root froghopper. The determination of the spatial distribution was conducted at Ourinhos and Guariba cities, São Paulo State, in three plots of 1.1 ha that had been mechanically harvested without burning and with a history of infestation with sugarcane root froghopper. The evaluations were made in three different periods, counting the number of both adults and nymphs at the base of the stools in 50% of the plot. The adults and the nymphs of M. fimbriolata were distributed in aggregated or contagious form and this pattern did not change during subsequent generations nor was influenced by either the level of infestation or cultivated variety. The data obtained in these experiments was used to estimate, for each site and sampling period, the dispersion index k and the number of samples needed to estimate nymph populations, considering different levels of precision. The data was also used to simulate results with different sample sizes and sampling patterns. The most adequate sampling plan to evaluate sugarcane root froghopper populations was determined using the confidence interval of the mean at P &#8804; 0.05 for the Relative Variation (RV) and Relative Precision (RP). The best results were obtained with 18 samples of 1 linear meter per hectare, distributed in the area in a systematic manner. For the evaluation of the commercial sampling method, two experiments were established at Ourinhos, using two 1.1 hectare plots. The number of biological forms in 300 spots of 1 linear meter in the plot (experimental sampling) were checked bi-weekly. Similarly, in the rest of the area, biological forms were counted in 4 spots of 2 linear meters per hectare (commercial sampling). Linear regression analysis presented that the commercial sampling method presented good efficiency for estimating nymphs populations but was not efficient in estimating adult populations. The sampling accuracy was low for both nymphs and adults, underestimating the true populations. The linear correlation between foam counts and nymph in both commercial and experimental sampling was high, with determination coefficient greater than 96%. The results indicate that, independent of the period and level of infestation, it is possible to estimate the population of sugarcane root froghopper nymphs by counting foam spots.

Made available in DSpace on 2017-07-25T19:30:56Z (GMT). No. of bitstreams: 1 Rodrigo Martins.pdf: 848584 bytes, checksum: eb0e32721a310dba481e0bdad0a05644 (MD5) Previous issue date: 2015-12-22<br>Annual losses of up to 25% of world corn production are stimated as a result of stalk lodging and root lodging. The use of resistant hybrids is the main method of control, though only use the visual evaluation is very limited. In this context, it is crucial to find methods to evaluate the quality of stalks with high correlationship with stalk loding that could be effective to detect level differences of resistance to stalk lodging. The objective of this study was to estimate the correlationship between agronomic characteristics and attributes associated with stalk lodging of corn hybrids and their inbred lines. Additionally, select genotypes that simultaneously have the highest number of characteristics associated with stalk quality and grain yield by principal component analysis. There were performed four experiments using corn hybrids and one experiment with inbred lines for evaluation of corn stalk penetration resistance as predictor of corn stalk quality in the 2013/2014 season. The experimental design was a randomized block design with twelve treatments and four reps for experiments with hybrid and sixteen treatments and three reps for the experiment with inbred lines. The results of the hybrids and inbred lines experiments were submited to Pearson correlation analysis through the GENES statistical software, and principal component analysis was performad by the R sorftware 2.15.2. The physical stalk quality represented mainly by stalk lodging, root lodging and corn stalk penetration resistance proved to be limiting for the selection of superior corn genotypes,because corn stalk lodging affected negatively the grain yield in corn hybrids. The stalk penetration resistance evaluation in inbred lines showed a significant negative correlation of 60% with stalk lodging, which makes this evaluation suitable for use to select inbred lines with enhanced physical quality of the stalks, enabling the detection of differences in stalk lodging resistance levels from the inbred lines. Using the principal component analysis was possible the identification of the corn inbred lines L2, L3, L6, L13 and L14, also the hybrids P30F53YH,30A37PW, DKB240PRO2 and H14 with the most favorable characteristics for stalk physical quality for corn grain yield.<br>Estima-se perdas anuais de até 25% na produção mundial de milho em consequência do acamamento e do quebramento do colmo. A utilização de híbridos resistentes é o principal método de controle, embora utilizar apenas a avaliação visual seja bastante limitada. Dessa forma, é imprescindível encontrar metodologias para avaliar a qualidade dos colmos com alta correlação com o quebramento de colmo à campo e que seja eficaz na detecção de diferenças nos níveis de resistência ao quebramento. O objetivo deste trabalho foi estimar as correlações entre características agronômicas e atributos associados ao quebramento de colmos de híbridos e linhagens endogâmicas de milho. Adicionalmente, selecionar genótipos que reúnam simultaneamente o maior número de características associadas à qualidade de colmos e ao rendimento de grãos através da análise de componentes principais. Foram realizados quatro experimentos de híbridos de milho e um de linhagens endogâmicas para avaliação da resistência dos colmos ao quebramento como preditor da qualidade de colmos em milho na safra 2013/2014. O delineamento experimental foi o de blocos ao acaso com doze tratamentos e quatro repetições para os experimentos com híbridos e dezesseis tratamentos e três repetições para o experimento com linhagens endogâmicas. Os dados dos experimentos de híbridos e de linhagens foram submetidos à análise de correlação de Pearson através do software estatístico GENES, e a análise de componentes principais através do software R versão 2.15.2. A qualidade física dos colmos representada principalmente pelas características quebramento de colmo, acamamento e resistência do colmo à penetração demonstraram ser limitantes para a seleção de genótipos superiores de milho, pois o quebramento dos colmos nos híbridos de milho afetou negativamente o rendimento de grãos nos experimentos. A avaliação da resistência à penetração do colmo nas linhagens endogâmicas teve correlação significativa e negativa de 60% com o quebramento de colmo, o que a torna passível de utilização para a seleção de linhagens com maior qualidade física dos colmos, possibilitando a detecção de diferenças nos níveis de resistência ao quebramento dos colmos entre as linhagens endogâmicas. Através da análise de componentes principais foi possível a identificação das linhagens endogâmicas de milho L2, L3, L6, L13 e L14 e os híbridos P30F53YH, 30A37PW, DKB240PRO2 e H14 com o maior número de características favoráveis para qualidade física dos colmos e potencial para o rendimento de grãos.

The control of particle emissions from an oil refinery is often difficult, due to changing operational conditions and the limited range of available treatment options. Excessive particle emissions have often been attributed start up problems with Fluidized Catalytic Cracker Units (FCCU) and little information is available regarding the exact composition and nature of these excessive emissions. Due to the complex nature of a FCCU, it has in the past been difficult to identify and control emissions, without the use of expensive end of pipe technologies. An Australian Oil Refinery, concerned with their catalyst emissions, sponsored this study of FCCU particle emissions. Due to the industrial nature of the project, a holistic approach to the management of emissions was taken, instead of a detailed investigation of a single issue. By looking at the broader range of issues, practical and useful outcomes can be achieved for the refinery. Initially, detailed emissions samplings were conducted to investigate the degree of particle emissions under start up conditions. Stack emissions were collected during a standard start up, and analysed to determine the particle size distribution and metal concentration of the emitted material. Three distinct stages of emissions were discovered, initially a high concentration of larger particles, followed by a peak in the very fine particles and finally a reduction of particle emissions to a more steady or normal operational state. The variation in particle emissions was caused by operational conditions, hardware design and catalyst characteristics. Fluctuations in the gas velocity through the system altered the ability of the cyclones to collect catalyst material. Also, the low bed level allowed air bypass to occur more readily, contributing to the increased emissions levels seen during the initial stage of the start up. Reduced fluidity characteristics of the circulating catalyst also affected the diplegs operations, altering the collection efficiency of the cyclone. During the loading of catalyst into the system, abraded material was quickly lost due to its particle size, contributing to fine particle emissions levels. More importantly, thermal fracturing of catalyst particles occurred when the cold catalyst was fed into the hot regenerator. Catalyst particles split causing the generation of large amounts of fine particle material, which is easily lost from the system. This loading of catalyst directly linked to the period of high concentration of fine particles in the emissions stream. It was found that metals, and in particular iron, calcium and silicon form a thick layer on the outside of the catalyst, with large irregular shaped metal ridges, forming along the surface of the particle. These ridges reduce the fluidity of the catalyst, leading to potential disruptions in the regenerator. In addition to this, the metal rich ridges are preferentially removed via attrition, causing metal rich material to be emitted into the atmosphere. To overcome these high particle emissions rates from the FCCU the refinery should only use calcinated catalyst to reduce the influence of thermal process and particle fracture and generation. Although the calcinated catalyst can fracture when added to the system, it is far less than that obtained with uncalicinated catalyst. To further reduce the risk of particle fracture due to thermal stresses the refinery should consider reducing the temperature gradients between the hot and cold catalyst. Due to the economics involved with the regenerator, possible pre-warming of catalyst before addition into system is the preferred option. This pre-heating of catalyst should also incorporate a controlled attrition stage to help remove the build up of metals on the surface of the particles whilst allowing this material to be collected before it can be released into the atmosphere. The remove of the metal crust will also improve the fluidity of the system and reduce the chance of catalyst blockages occurring. Finally, modelling of the system has shown that control of key parameters such as particle size and gas velocity are essential to the management of air emissions. The refinery should look at adjusting start up procedures to remove fluctuations in these key parameters. Also the refinery should be careful in using correlation found in the literature to predicted operational conditions in the system as these correlations are misleading when used under industrial situations.

Lo scopo del presente elaborato di tesi è la creazione di uno strumento utile ai fini dell’informatica forense per la rilevazione di Trojan ad Accesso Remoto dal traffico di rete da essi generato. Il RAT è un malware che consente a un utente non autorizzato il controllo amministrativo da remoto del dispositivo su cui è installato. L’utilizzo dei RAT è illegale ad eccezion fatta per i casi ammessi dal diritto, la cui trattazione sarà oggetto del capitolo Secondo. L’attività di rilevazione è quindi da inquadrare in quelli che sono gli utilizzi illeciti di tali strumenti. Sotto il profilo giuridico sarà analizzato l’impiego dei RAT nelle fonti giuridiche riguardanti le intercettazioni prendendo in esame i diritti fondamentali di libertà di espressione, l’inviolabilità delle comunicazioni discernendo l’attività di RAT da strumento per la cd. perquisizione on-line, e quindi come strumento non tipico per l’ottenimento di prove, a strumento per l’intercettazione tra presenti in seno alla cosiddetta ”riforma Orlando” del c.p.p. Passando invece al punto di vista funzionale, il progetto è orientato sull’intercettazione, indicizzazione e analisi del traffico dati riguardante un telefono con RAT installato per rilevare patterns nella rete utili per l’identificazione, senza alterare il telefono. La cattura dei pacchetti avverrà tramite l’adozione di un wiretapper, che dirotterà i pacchetti provenienti ed indirizzati al telefono in esame. Contestualmente alla cattura dei dati effettuata con Wireshark da riga di comando7, i pacchetti saranno caricati su Elasticsearch, un motore di ricerca full text, e analizzati dall’interfaccia web Kibana, opportunamente configurata per mostrare attività anomale e pattern inusuali nel traffico di rete. L’intento del presente elaborato risiede quindi nell’esaminare gli aspetti giuridici dei RAT, realizzando un dispositivo che permetta l’autotutela nei casi non previsti dagli istituti giuridici presi in esame.

In this paper is described creation of a robot in Robot Operating system (ROS) withAckermann steering. It contains the principle of Ackermann steering geometry, search ofcontroller boards and basics of ROS structure. A RC car with connected PixHawk controlleris used as a basis of the robot. On the robot is placed an onboard computer Raspberry Pi3 with running ROS. This computer is connected to a laptop through Wi-Fi network. Theprocedure of starting up the robot and ROS is also described in this paper, as well asdesign of the graphical user interface (GUI) that will display sensory data and allow otherfunctionality. Another part of thesis explains principle of an optical encoder and how tocreate your own encoder which can detect rotation of a wheel. This is used to implementrobot odometry. The structure of ROS navigation library is analyzed with regards to itscommissioning. Implementation of the GUI and navigation library will follow in the masterthesis.

碩士<br>國立中正大學<br>資訊工程研究所<br>81<br>In the neural network computing, the false memory of a Stack Filter is defined a signal or pattern set in which each element is undesired but still preserved by that filter. Whatever desired or undesired a signal ( or pattern ) is preserved, it is a root signal ( or pattern ) of the root set for its corresponding Stack Filters -- even it is an element of the false memory, it is still a root signal. In traditional designs, false memory definitely occurred and it made much more confusion and waste for Stack Filters to recognize what they want. In previous research, people have devoted to deriving a heuristic algorithm to finding a near optimal Stack Filter. However, it is considerably time consuming based on brute force to exhaust all the possible to obtain the near optimal solution. The notion of Two-Layer Stack Filters are thus introduced in this thesis to survey their efficiency and performance by different width of sliding windows and various types of cascades of One-Layer Stack Filters. They are proposed to be implemented by the combinations of simple One-Layer Stack Filters to accomplish more complicated work with nice gains. In this thesis we build some classes os Two-Layer Stack Filters based on (2N+1)-monotonic signals, and survey their root structures and filtering behaviors. All of these Two-Layer Stack Filters are proven better than their corresponding One-Layer Stack Filters by means of rigorous approaches and the best combinations are also proposed and proved.

碩士<br>國立中正大學<br>資訊工程研究所<br>81<br>Stack filters are nonlinear digital filters that are based on positive Boolean functions as the window operators and contain some roots (fixed points) which are invariant under filtering operations. For some applications, it is useful to understand the root structure of a stack filter (e.g. median filter). Provably, the problem determining whether a specific signal is a fixed point of some stack filter can be regarded as a pattern recognizing problem by a deterministic finite automaton which corresponds to the specified stack filter and generates the regular language. We will introduce a concise and direct algorithm to obtain a simplified deterministic finite automaton that describes the root set of a specified stack filter. From the automaton, we can easily determine root properties of a stack filter. We will also introduce a new class of stack filters called K-monotone stack filters that are generalizations of median filters and apply our algorithm to analyze root properties of K-monotone stack filters (K .ltorsim. 2N+1). An open problem concerning the root structures of median filters under circular appending strategy is analyzed by the approach of state description.

Thesis (Ph.D.)--State University of New York at Buffalo, 2005.<br>Title from PDF title page (viewed on May 10, 2006) Available through UMI ProQuest Digital Dissertations. Thesis adviser: Gottdiener, Mark. Includes bibliographical references.