Search

One of the primary constraints in upland rice cultivation is the disease blast (Magnaporthe oryzae), which can provide reduction up to 100% of the grain yield The use of silicon with benefi cial microorganisms (bioagents) can be an alternative for the control of this disease and to provide an increase in the productivity of the rice grain. The objective of this work was to study the eff ect of rates of silicon with bioagents in blast suppression and grain yield of upland rice. The methodology used was tests carried out in field conditions, in two different areas: Capivara and Palmital farms, during the growing season 2015/2016. The experimental design was in a split-plot scheme with four replications. In the main plots were the silicon fertilization rates (0, 2, 4 and 8 ton ha-1) and in the subplots was the bioagents (1-without bioagents, 2-Pseudomonas fluorescens, 3-Burkholderia pyrrocinia, 4-Trichoderma asperellum, 5-a mixture of the three bioagents). The results showed that the use of 2 ton ha-1 of silicon with a mixture of bioagents was the best treatment to control leaf blast. Besides, from rates, 2 to 6 ton ha-1 of silicon in Capivara Farm and up to 8 ton ha-1 of silicon in Palmital Farm provided the highest grain yield. A mixture of bioagents provided the highest grain yield. In this sense, it was concluded that the best recommendation to connect blast control, grain yield and reduced amount of silicon was the use of 2 ton ha-1 of silicon with the mixture of bioagents. Made available in DSpace on 2021-12-02T14:00:55Z (GMT). No. of bitstreams: 1 jpsp-2021.pdf: 463307 bytes, checksum: a70c96be86c141bc7648f0b3558d6b5d (MD5) Previous issue date: 2021

The use of beneficial microorganisms in crop systems can contribute to sustainable agriculture by promoting improvements in crop development and grain yield without damaging the environment. However, there is much uncertainty surrounding the effects of using a combination of microorganisms to promote plant development. The objective of this work was to determine the effects of microorganism species individually and in combination on the biomass production, gas exchange and nutrient contents in the shoots and roots of soybean plants. The experimental design was completely randomized, with 30 treatments and three replicates. The treatments consisted of the application of the rhizobacteria BRM 32109, BRM 32110 and 1301 (Bacillussp.); BRM 32111 and BRM 32112 (Pseudomonas sp.); BRM 32113 (Burkholderia sp.); BRM 32114 (Serratia sp.); Ab-V5 (Azospirillum bras ilense) and 1381 (Azospirillum sp.); the fungus Trichoderma asperellum (a mixture of the isolates UFRA. T06, UFRA. T09, UFRA. T12 and UFRA. T52); 19 combinations of these microorganisms, and a control (no microorganisms). At sowing, the soil was treated with Bradyrhizobium, and then the soybean seeds were inoculated. The microorganism suspension was applied in each treatment at 7 days after planting (DAP) in the soil and at 21 DAP on the seedlings. The Trichoderma pool, Ab-V5, 1301 + 32110, 1301 + 32114, 1301 + Ab-V5 and 32110 + Ab-V5 treatments resulted in significantly higher total biomass accumulation in the soybean plants, with values that were, on average, 25% higher than that in the control treatment. Our results suggest that the use of beneficial microorganisms in cropping systems is a promising technique. RESUMO O uso de microrganismos benéficos nos sistemas de cultivo pode contribuir para a agricultura sustentável, promovendo melhorias no desenvolvimento das culturas e na produção de grãos sem danificar o meio ambiente. No entanto, há muita incerteza quanto aos efeitos do uso de uma combinação de microrganismos para promover o desenvolvimento da planta. O objetivo deste trabalho foi determinar os efeitos das espécies de microrganismos individualmente e em combinação na produção de biomassa, trocas gasosas e conteúdo de nutrientes na parte aérea e raízes das plantas de soja. O delineamento experimental foi inteiramente casualizado, com 30 tratamentos e três repetições. Os tratamentos consistiram na aplicação das rizobactérias BRM 32109, BRM 32110 e 1301 (Bacillus sp.); BRM 32111 e BRM 32112 (Pseudomonas sp.); BRM 32113 (Burkholderia sp.); BRM 32114 (Serratia sp.); Ab-V5 (Azospirillum brasilense) e 1381 (Azospirillum sp.); o fungo Trichoderma asperellum (uma mistura dos isolados UFRA. T06, UFRA. T09, UFRA. T12 e UFRA. T52); 19 combinações desses microrganismos e um controle (sem microrganismos). Na semeadura, o solo foi tratado com Bradyrhizobium e as sementes de soja foram inoculadas. A suspensão de microrganismos foi aplicada em cada tratamento aos 7 dias após o plantio (DAP) no solo e aos 21 DAP nas mudas. Os tratamentos pool de Trichoderma, Ab-V5, 1301 + 32110, 1301 + 32114, 1301 + Ab-V5 e 32110 + Ab-V5 resultaram em acúmulo de biomassa total significativamente maior nas plantas de soja, com valores, em média, 25% superior ao tratamento controle. Nossos resultados sugerem que o uso de microrganismos benéficos em sistemas de cultivo é uma técnica promissora.

O uso de tecnologias inovadoras e sustentáveis que primem pelo desenvolvimento de sistemas agrícolas produtivos, como as rizobactérias multifuncionais, são fundamentais para garantir a segurança e qualidade dos alimentos. Diante disso, esse estudo de caráter teórico, realizado por meio de uma pesquisa bibliográfica de caráter exploratório e abordagem qualitativa, teve como objetivo trazer informações referentes às rizobactérias multifuncionais abordando os aspectos gerais, características principais, alguns gêneros de importância agrícola, seus principais mecanismos de ação e a importância da coinoculação. Rizobactérias multifuncionais são bactérias rizosféricas, endofíticas ou simbióticas, que possuem a capacidade de proporcionar melhoria no crescimento das plantas, potencializando o aumento da produtividade. A utilização dessas bactérias nos sistemas agrícolas tem se mostrado uma tecnologia inovadora e sustentável devido aos diferentes mecanismos de ação, que podem ser diretos e indiretos, para beneficiar as plantas e o meio ambiente. As rizobactérias multifuncionais promovem o crescimento vegetal e a supressão de doenças e, com isso, viabilizam a redução do uso de insumos sintéticos como fertilizantes e agrotóxicos. Existem diferentes gêneros de rizobactérias multifuncionais e elas podem apresentar sinergismo e, portanto, maior eficiência utilizando-se a técnica de coinoculação. Esta técnica consiste em adicionar mais de um microrganismo reconhecidamente benéfico às plantas, visando maximizar a contribuição dos mesmos. A coinoculação proporciona vários benefícios para o maior desenvolvimento das plantas, como o aumento do sistema radicular, o que possibilita maior aproveitamento dos fertilizantes, favorece a planta em situações de deficiência hídrica e incrementa a produtividade. No entanto, diversos desafios ainda precisam ser superados como a seleção de estirpes eficientes para culturas específicas, à compatibilidade com os produtos utilizados no tratamento de sementes e a obtenção de resultados agronômicos consistentes em ensaios de campo. Portanto, estudos nesse sentido são muito importantes para aumentar os conhecimentos sobre rizobactérias multifuncionais e contribuir para tornar os sistemas agrícolas mais eficientes e sustentáveis. Made available in DSpace on 2022-07-07T14:21:01Z (GMT). No. of bitstreams: 1 rsd-2022.pdf: 756108 bytes, checksum: cdd62b9b307d62d8407904ba64b937e8 (MD5) Previous issue date: 2022

Para o crescimento e desenvolvimento as plantas, na natureza, contam com os benefícios de microrganismos residentes em sua rizosfera. Rizobactérias promotoras de crescimento vegetal (RPCV) são exemplos desses microrganismos que interagem de forma benéfica com espécies vegetais. Portanto, a inoculação de sementes com RPCV pode representar uma alternativa importante e sustentável para melhorar o desenvolvimento inicial e a produção de plantas cultivadas. Objetivou-se com esse estudo determinar o efeito da microbiolização de sementes com RPCV no comprimento radicular de plântulas de arroz irrigado. Em condições controladas, conduziram-se dois experimentos com cultivares de arroz irrigado (BRS Catiana e A 702 CL), em delineamento inteiramente casualizado, com sete tratamentos e 10 repetições. Os tratamentos constituíram-se de seis microrganismos: BRM32109 (Bacillus sp.), BRM32110 (Bacillus sp.), BRM32111 (Pseudomonas sp.), BRM32112 (Pseudomonas fluorescens), BRM32113 (Burkholderia pyrrocinia), BRM32114 (Serratia sp.) e um controle (sem microrganismo). Os dados foram submetidos à análise de variância, as médias entre os tratamentos com RPCV foram comparadas pelo teste LSD (p≤0,05) e, os tratamentos com microrganismos foram comparados individualmente com o controle pelo teste de Dunnett (p≤0,05). Somente a cultivar BRS Catiana apresentou diferença entre os tratamentos. Os maiores comprimentos radiculares foram apresentados pelas sementes tratadas com os isolados BRM32110, BRM32112, BRM32109 e BRM32114. Para ambas cultivares houve significância quando comparado microrganismos e controle. Destaque para as sementes da cultivar BRS Catiana, que quando tratadas com os isolados BRM32110 e BRM32112 apresentaram aumento médio de 25,7% no comprimento radicular, em comparação com o tratamento controle. Para a cultivar A 702 CL, todos os microrganismos proporcionaram incrementos com um valor médio de 31% no comprimento radicular das plântulas de arroz. Com base nos resultados pode-se inferir que as RPCV proporcionam incrementos significativos no comprimento radicular de plântulas de cultivares de arroz irrigado.

HIGHLIGHTS Multifunctional microorganisms promote the nutrient enrichment in Crotalaria plants. Cover crop residues are vital in managing soil fertility. Nutritionally improved cover crops increase soil nutrient levels for the subsequent crop. RESUMO Plantas de cobertura são essenciais na recuperação da produtividade do solo. Crotalaria é uma das mais eficientes espécies de leguminosas em termo de produção de biomassa e fixação de nitrogênio. Objetivou-se neste estudo avaliar o efeito de microorganismos multifuncionais no desempenho agronômico de Crotalaria juncea, C. spectabilis e C. ochroleuca. O experimento foi conduzido em casa de vegetação, em delineamento inteiramente casualizado, com quatro repetições. Os tratamentos consistiram em seis isolados de rizobactérias (BRM 32109 e BRM 32110 (Bacillus sp.), BRM 32111 e BRM 32112 (Pseudomonas sp.), BRM 32113 (Burkholderia sp.), BRM 32114 (Serratia sp.)) e um isolado fúngico (Trichoderma sp. (T-26)), além do tratamento controle (sem microrganismo). O principal efeito dos microorganismos multifuncionais sobre as três espécies de Crotalaria foi o aumento da concentração de macro e micronutrientes. Enxofre e zinco aumentaram na raiz de plantas de C. juncea; cálcio e enxofre na parte aérea de plantas de C. spectabilis; e plantas de C. ochroleuca apresentaram maior concentração de fósforo e cobre na parte aérea e de zinco e cobre na raiz. Em resumo, o melhor status nutricional em plantas de Crotalaria afeta diretamente a disponibilidade de nutrientes para a cultura subsequente.

Rice the main source of energy to maintain the metabolism for almost four billion people worldwide. Riceplants treated with multifunctional microorganisms may be a good wayfor sustainable improvement of crop grain yield. Aimedstudy the effect of types and ways of microorganisms application in tropical lowland rice production, evaluated by biomass production and gas exchange. The greenhouse trial was in a completely randomized design, in factorial scheme 7 x 3 + 1, with four replication. Treatments were the combination of seven microorganisms: Bacillussp. (BRM32109 e BRM32110); Pseudomonas fluorescens(BRM32111); Pseudomonassp. (BRM32112); Burkholderia pyrrocinia(BRM32113); Serratiasp. (BRM32114) and Trichoderma asperellumpool (UFRA.T06 + UFRA.T09 + UFRA.T12 + UFRA.T52), with three forms of application (1. microbiolized seed; 2. microbiolized seed + soil drenched with microorganism at eight and 15 days after sowing (DAS)and 3. microbiolized seed + microorganism spray plant at eight and 15 DAS). Microbiolized seed was the best form of application,which allowed highest instantaneous carboxylation efficiency and yield of biomassproduction in lowland rice. Rhizobcteria BRM32114, followed by BRM32111, BRM32112 and fungi T. asperellumimproved, an average, 17% in instantaneous carboxylation efficiency and 20% in dry shoot biomass production of lowland rice compared to the control plants. Made available in DSpace on 2021-11-30T13:00:35Z (GMT). No. of bitstreams: 1 ca-2021.pdf: 499279 bytes, checksum: 0655c967052fac01e7750c100da28826 (MD5) Previous issue date: 2021

Cultivation of cover crops in the off-season and the use of multifunctional microorganisms are strategic technologies to ensure sustainability in upland rice production. The objective of this work was to determine the effect of mix of cover crops cultivated in the off-season and multifunctional microorganisms on the growth promotion of upland rice plants, under no-tillage systems conducted in the Brazilian Cerrado. The experimental design was a complete randomized blocks in a 6x2 factorial scheme with four replications. The treatments consisted of a combination of six soil covering plants 1. Fallow (control); 2. millet (Pennisetum glaucum) and crotalaria (Crotalaria juncea, C. spectabilis and C. ochroleuca); 3. millet and pigeon pea (Cajanus cajanus); 4. millet and Urochoa ruziziensis; 5. millet, U. ruziziensis and pigeon pea; and 6. millet and buckwheat (Fagopyrum esculentum)), with or without the application of coinoculants 1301 (Bacillus sp.) + Azospirillum sp. The mix of cover crops millet + U. ruziziensis and millet + U. ruziziensis + pigeon pea recorded the largest biomass production and the highest nutrient content in the straw. Rice plants cultivated after millet + pigeon pea showed largest transpiration and stomata conductance. The application of multifunctional microorganisms contributed to an increase of 29% in the photosynthetic rates of rice plants. The highest upland rice grain yield was achieved after mix of millet + crotalaria (Crotalaria juncea, C. spectabilis and C. ochroleuca). The application of multifunctional microorganisms increased the mass of 1000 grains, but does not affect rice grain yield. Our results showed that cover crops significantly affected rice grain yield and the multifunctional microorganisms affected grain quality. Made available in DSpace on 2021-11-30T12:01:27Z (GMT). No. of bitstreams: 1 ajcs-2021.pdf: 896700 bytes, checksum: 372b36d66a851931588390cdd46565d3 (MD5) Previous issue date: 2021

Microrganismos multifuncionais são microrganismos benéficos que apresentam mecanismos diretos e indiretos de promoção de crescimento vegetal e apresentam um papel importante como uma tecnologia alternativa rumo à escala para uma agricultura sustentável. O aumento da demanda pela produção agrícola com uma redução significativa do uso de fertilizantes e pesticidas sintéticos é um grande desafio na atualidade. O estudo desses microrganismos vem merecendo destaque nos últimos anos em razão da grande demanda por tecnologias sustentáveis, podendo reduzir os custos de produção, aumentando a produtividade e a rentabilidade do agronegócio. A aplicação de microrganismos multifuncionais através de mecanismos diretos e indiretos tem mostrado que é possível tornar as práticas de manejo das culturas ambientalmente mais sustentáveis. Os mecanismos dos microrganismos multifuncionais incluem a regulação do equilíbrio hormonal, solubilização de nutrientes na solução do solo e indução de resistência contra patógenos. O objetivo do trabalho foi trazer informações referentes aos microrganismos multifuncionais priorizando os aspectos gerais, as características dos microrganismos (rizobactérias e fungos) promotores do crescimento vegetal e seus principais mecanismos de ação. Em resumo, conclui-se que os microrganismos multifuncionais possuem diversas características favoráveis para serem utilizados como promotores de crescimento das plantas, na agricultura sustentável. Made available in DSpace on 2021-11-30T12:01:57Z (GMT). No. of bitstreams: 1 rsd-2021.pdf: 374159 bytes, checksum: decb254a9dedf29116c85ffc72c7ccdf (MD5) Previous issue date: 2021

Multifunctional microorganisms (MM) are able of colonizing root system and shoots and then, provide beneficial effects to the plants. Thus, the objective of this study was test whether multifunctional microorganisms affect gas exchange, macronutrient content, yield components and bean grain yield. A completely randomized design with twenty-six treatments and three replications was used under controlled conditions. Treatments consisted of the application of MM and its combinations in pairs, with nine rhizobacteria isolates BRM 32109, BRM 32110 and 1301 (Bacillus sp.), BRM 32111 and BRM 32112 (Pseudomonas sp.), BRM 32113 (Burkholderia sp.), BRM 32114 (Serratia sp.), 1381 (Azospirillum sp.) and Ab-V5 (Azospirillum brasiliense), an edaphic fungal isolate T-26 (Trichoderma koningiopsis), and a control (without MM). The isolates Ab-V5 and BRM 32112, in addition to the combinations BRM 32114 + T-26, 1301 + BRM 32110 and BRM 32114 + BRM 32110 were the highlights treatments, since they provided increases in gas exchange, in the content of macronutrients and in the agronomic performance. Made available in DSpace on 2022-05-10T21:12:29Z (GMT). No. of bitstreams: 1 rbca-2021.pdf: 1853438 bytes, checksum: 5842a88c7c5900405236819206a5d6c0 (MD5) Previous issue date: 2021

Tropical flooded rice production systems require a high input of fertilizers and chemical defensive. The use of plant growth-promoting rhizobacteria (PGPR), a sustainable component of this system, can increase nutrient-use efficiency and lead to significant increases in the grain yield of tropical flooded rice crop. This study aimed to determine the effect of the microorganism BRM 32110 (Bacillus thuringiensis) in combination with nitrogen (N), phosphorus (P) and potassium (K) application rates on the physiological and agronomic performance of tropical flooded rice plants. Trials were performed in the 2016/2017 growing season in Formoso do Araguaia, a city in Tocantins state, Brazil. Three independent experiments (E1, E2, and E3) were performed in a randomized block design in a 4 x 2 factorial scheme with three replications. E1 comprised four N application rates (0, 40, 80 and 120 kg N ha-1) with and without the addition of BRM 32110, E2 comprised four P2O5 application rates (0, 40, 80 and 120 kg P2O5 ha-1) with or without BRM 32110, and E3 comprised four K2O application rates (0, 20, 40 and 60 kg K2O ha-1) with and without BRM 32110. In fertile soil, there were no interactions between the rhizobacterium BRM 32110 and the N, P or K application rates. BRM 32110 improved nutrient uptake and, on average, increased shoot dry matter by 8%, photosynthesis rate by 14% and grain yield by 11% in the flooded rice plants. Our results suggest that the use of multifunctional microorganisms is a good strategy for improving flooded rice grain yield sustainably. RESUMO Os sistemas tropicais de produção de arroz inundado requerem uma alta entrada de fertilizantes e defensivos químicos. O uso de rizobactérias promotoras de crescimento de plantas (RPCP), um componente sustentável desse sistema, pode aumentar a eficiência do uso de nutrientes e levar a aumentos significativos no rendimento de grãos das culturas tropicais de arroz inundado. Este estudo teve como objetivo determinar o efeito do microrganismo BRM 32110 (Bacillus thuringiensis) em combinação com doses aplicaas de nitrogênio (N), fósforo (P) e potássio (K) no desempenho fisiológico e agronômico de plantas de arroz inundadas no ambiente tropical. Os ensaios foram realizados na safra agrícola 2016/2017 em Formoso do Araguaia, cidade no estado do Tocantins, Brasil. Três experimentos independentes (E1, E2 e E3) foram realizados em delineamento de blocos ao acaso, em esquema fatorial 4 x 2, com três repetições. E1 compreendeu quatro doses aplicadas de N (0, 40, 80 e 120 kg N ha-1) com e sem a adição de BRM 32110, E2 compreendeu quatro doses aplicadas de P2O5 (0, 40, 80 e 120 kg de P2O5 ha-1) com ou sem BRM 32110, e E3 compreendeu quatro taxas de aplicação de K2O (0, 20, 40 e 60 kg K2O ha-1) com e sem BRM 32110. Em solo fértil, não houve interações entre a rizobacteria BRM 32110 e taxas aplicadas de N, P ou K. O BRM 32110 melhorou a captação de nutrientes e, em média, aumentou a matéria seca da parte aérea em 8%, a taxa de fotossíntese em 14% e a produtividade de grãos em 11% nas plantas de arroz inundadas. Nossos resultados sugerem que o uso de microrganismos multifuncionais é uma boa estratégia para melhorar o rendimento de grãos de arroz inundado de forma sustentável.

Multifunctional microorganisms can contribute significantly to improve plant performance and are innovative technology for sustainable development. Thus, objective of this study was to determine the effect of bioagents applied alone or in mix on the performance of upland rice. The experiment was conducted in a greenhouse in a completely randomized design with four replications. The 26 treatments consisted of the rhizobacteria Bacillus sp. (BRM 32109, BRM 32110 and 1301), Azospirillum sp. (1381), Azospirillum brasilense (Ab-V5), Pseudomonas sp. (BRM 32112), Pseudomonas fluorescens (BRM 32111), Burkholderia pyrrocinia (BRM 32113), Serratia sp. (BRM 32114), and a fungal genus formed by a pool of Trichoderma asperellum (T-06, T-09, T-12, and T-52), applied alone or in mix, plus a control treatment without microorganism application. The most effective treatments were the mixes of microorganisms 1301 + Ab-V5 and BRM 32114 + pool of Trichoderma asperellum, as they provided an average increase of 123 and 88% in the number of panicles and 206 and 167% in the grain yield of upland rice plants, respectively. Mixes of 1301 + Ab-V5, BRM 32114 + Trichoderma asperellum pool, BRM 32110 + BRM 32114, BRM 32110 + Ab-V5, 1301 + BRM 32110 and 1381 + Trichoderma asperellum pool also provided better morphophysiological performance in rice plants (photosynthetic rate, carboxylation efficiency, number of tillers, shoot dry biomass and nutrient content in shoot and root). Therefore, the use of multifunctional microorganisms in the management of upland rice was efficient in its ability to provide better development of plants. RESUMO Microrganismos multifuncionais podem contribuir significativamente para melhorar o desempenho das plantas, sendo tecnologia inovadora quando se visa o desenvolvimento sustentável. Assim, objetivou-se determinar o efeito de microrganismos multifuncionais aplicados isolados ou em mix sobre o desempenho do arroz de terras altas. O experimento foi conduzido em casa de vegetação, em delineamento inteiramente casualizado, com quatro repetições. Os 26 tratamentos consistiram das rizobactérias Bacillus sp. (BRM 32109, BRM 32110 e 1301), Azospirillum sp. (1381), Azospirillum brasilense (Ab-V5), Pseudomonas sp. (BRM 32112), Pseudomonas fluorescens (BRM 32111), Burkholderia pyrrocinia (BRM 32113), Serratia sp. (BRM 32114), e um gênero fúngico formando um pool de Trichoderma asperellum (T-06, T-09, T-12, e T-52), aplicados isoladamente ou em consórcio, mais o tratamento controle, sem aplicação de microrganismos. Os tratamentos mais efetivos foram os mixes de microrganismos 1301 + Ab-V5 e BRM 32114 + pool de Trichoderma asperellum, uma vez que proporcionaram aumento, em média, de 123% e 88% no número de panículas e de 206 e 167% na produtividade de grão do arroz de terras altas, respectivamente. Os consórcios 1301 + Ab-V5, BRM 32114 + pool de Trichoderma asperellum, BRM 32110 + BRM 32114, BRM 32110 + Ab-V5, 1301 + BRM 32110 e 1381 + pool de Trichoderma asperellum, também proporcionaram maior desempenho morfofisiológico nas plantas de arroz (taxa fotossintética, eficiência de carboxilação, número de perfilhos, biomassa seca de parte aérea e teor de nutrientes na parte aérea e raiz das plantas). Portanto, o uso de microrganismos multifuncionais no manejo do arroz de terras altas foi eficiente em sua capacidade de proporcionar maior desenvolvimento das plantas.

Beneficial microorganisms participate in different processes that affect transformation of soil nutrients, including phosphorus (P), making them available for plants. However, there are few studies about the use of beneficial microorganism and P fertilization in the development of aerobic rice. The objective was to determine the effect of Serratia spp. isolate BRM 32114 and doses of P at sowing on the production of biomass, gas exchange, nutrient content in leaves and grain, grain yield and its components of aerobic rice. The field experiments were conducted over two growing seasons, 2015/16 and 2016/17, under a no-tillage system in the Brazilian Cerrado. The experimental design was a complete randomized block in a factorial 4x2x2 scheme, with four replications. The treatments consisted of four P2O5 doses (0, 40, 80 and 120 kg ha-1) with or without rhizobacterium (2) in two growing seasons (2). Phosphorus rates increased the number of panicles and grain yield of aerobic rice, and the grain yield was higher in Serratia inoculation compared to no inoculation. The Serratia spp. strain BRM 32114 inserted in the production system of aerobic rice, under no-tillage, promoted gas exchange activity; enriched the K+, Ca+2 and Mg+2 content in leaves; enhanced biomass accumulation (13%), and resulted in a higher number of panicles per plant (11%) and grain yield (19%) than untreated plants. Therefore, this beneficial microorganism is a promising technology for potential incorporation into cropping systems in Tropical regions of the world. Made available in DSpace on 2020-11-07T09:15:14Z (GMT). No. of bitstreams: 1 AJCS-2020.pdf: 978301 bytes, checksum: 84f8a153d98db66632d308f5ed824b02 (MD5) Previous issue date: 2020

Rice blast (Magnaporthe oryzae) limits rice (Oryza sativa) grain yields worldwide. The objective of this investigation was to morphologically, biochemically, and molecularly characterize six bacterial isolates, BRM 32109, BRM 32110, BRM 32111, BRM 32112, BRM 32113, and BRM 32114, and to determine their potential as antagonists to M. oryzae. Morphological characterization was based on colony formation and color, Gram staining, and fluorescent pigment production. Biochemical studies were based on cellulase, chitinase, phosphatase, indoleacetic acid, and siderophore production, as well as biofilm formation. The molecular identification used specific primers for PCR amplification of the 16S rRNA region, followed by sequencing. The antagonism studies involved three experiments, which had randomized designs. Two of them were conducted in laboratory conditions, pairing bacterial colonies and M. oryzae, using bacterial filtrates, and the third was conducted in greenhouse conditions. BRM 32111 and BRM 32112 were identified as Pseudomonas sp., BRM 32113 as Burkholderia sp., BRM 32114 as Serratia sp., and BRM 32110 and BRM 32109 as Bacillus spp. BRM 32112, BRM 32111, and BRM 32113 inhibited the colony of M. oryzae by 68%, 65%, and 48%, respectively. The bacterial suspensions of the BRM 32111, BRM 32112, and BRM 3212 filtrates suppressed leaf blast by 81.0, 79.2, and 66.3%, respectively. BRM 32111 and BRM 32112 were determined to be antagonists of M. oryzae and were found to solubilize phosphate, produce siderophores and cellulose, form biofilms, and suppress leaf blast. These isolates should be further investigated as potential biological control agents for leaf blast control. Made available in DSpace on 2020-11-07T09:15:38Z (GMT). No. of bitstreams: 1 rcaatinga-2020.pdf: 747526 bytes, checksum: bd0d8c5b49b96b0545bd0195853d2d08 (MD5) Previous issue date: 2020

As plantas de cobertura têm a finalidade de cobrir, proteger o solo e fornecer palhada para o Sistema de Plantio Direto (SPD), e são cultivadas em áreas que seriam destinadas ao pousio ou antecedendo culturas comerciais. O uso dessas plantas no SPD na região do Cerrado pode proporcionar melhorias nas condições físicas, químicas e biológicas dos solos, bem como na saúde e desenvolvimento das culturas de interesse econômico. Na escolha da planta de cobertura para a sua área o produtor deve optar por espécies que atendam às suas necessidades e que tenham bom desenvolvimento na região. Existe uma grande variedade de espécies adaptadas à região do Cerrado, principalmente do grupo das gramíneas ou leguminosas, que podem proporcionar benefícios distintos ao solo e às culturas comerciais. As espécies também possuem características diferentes que podem favorecer o melhor aproveitamento dos recursos do meio, ou ter efeito sinergético nos benefícios proporcionados pelo uso de somente uma espécie de planta de cobertura. Assim, a utilização de mix de plantas de cobertura, principalmente com espécies que apresentem características contrastantes, vem crescendo uma vez que podem proporcionar maiores benefícios ao sistema do que o cultivo de espécies solteiras, como maior disponibilidade de nutrientes para as culturas e maior proteção do solo. Portanto o uso de plantas de cobertura, isoladas ou em mix, é uma ótima alternativa para melhorar a qualidade do solo e beneficiar as culturas comerciais em sucessão, podendo contribuir para a intensificação da agricultura sustentável no Cerrado. Made available in DSpace on 2021-12-01T19:00:55Z (GMT). No. of bitstreams: 1 rsd-2021.pdf: 202841 bytes, checksum: 8c27b6cc0006b07f333bd25f90d3e6aa (MD5) Previous issue date: 2021

Potassium (K) is the second most uptaken nutrient by upland rice crops. Beneficial microorganisms, such as Rhizobacteria participate in different processes that affect transformation of soil nutrients, making them available to plants. However, there are no information about the use of Rhizobacteria and different rates of K fertilization in this crop. To elucidate this interaction, the objective of this study was to determine the effect of the rhizobacteria Serratia spp. strain BRM 32114 and doses of K at sowing fertilization on upland rice development. The experimental design was a complete randomized block in a factorial 4 × 2 scheme with four replications, under no-tillage systems conducted in the Brazilian Cerrado during 2015/16 and 2016/17 growing season. The treatments consisted of four K2O doses (0, 20, 40 and 60 kg ha-1) without or with rhizobacteria applied three times in the field (on the seeds, sprayed over the soil, seven days after sowing and sprayed on the plants, 14 days after sowing). Biomass production, gas exchange, nutrient content in leaves and grain, yield components and grain yield were evaluated. The use of BRM 32114 applied in soil with high levels of K provided increase in the contents of P, Ca, Mg, Fe and Zn in rice leaves. The results showed enhances in plant biomass (7.2%), the number of panicles per plant (10%), and the grain yield of upland rice (16.3%). Therefore, our results allow inferring that the use of microorganism BRM 32114 provided significant improvements in rice growth/development, which resulted in higher grain yield over two consecutive growing seasons under field conditions. It showed that the bioagent Serratia spp. is promising to be incorporated into crop systems. Made available in DSpace on 2019-07-09T00:43:34Z (GMT). No. of bitstreams: 1 CNPAF2019ajcs.pdf: 846805 bytes, checksum: 1176365777be9c642ed27c8080a63087 (MD5) Previous issue date: 2019

This is the first study to detect Magnaporthe oryzae rice isolates carrying the MAT1-1 idiomorph in Brazil. Despite the low frequency of the MAT1-1 idiomorph, the study showed that sexual reproduction is possible in the northern riceproducing regions of Brazil. Made available in DSpace on 2019-11-20T18:11:17Z (GMT). No. of bitstreams: 1 CNPAF2019ndr.pdf: 516212 bytes, checksum: bf91e457ffc37162bcb1d33c85b8a286 (MD5) Previous issue date: 2019

Environmentally friendly technologies, such as the use of bacteria (e.g. Bacillus spp.) to control fungal diseases of rice (Oryza sativa L.), represent a promising alternative for the sustainability of agricultural ecosystems. The present work aimed to isolate, identify, and evaluate (in vitro) various Bacillus spp. from the rice phylloplane for their potential to control the rice fungus Magnaporthe oryzae. Samples were taken from the phylloplane of healthy young rice plants growing in commercial fields in ten municipalities of Maranhão (Brazil), and Bacillus spp. were subsequently isolated and molecularly identified. Both experiments utilized a randomized design, and data were submitted to analysis of variance as well as means comparison by the Tukey test. Twelve bacterial isolates were obtained and identified. Using a control isolate (B25), four in vitro M. oryzae-inhibition methods were compared, with the ?circle? method ultimately providing the highest mycelium growth inhibition. The most promising experimental isolates for biological control were then identified as B. methylotrophicus isolates B41, B31, and B22, which achieved 90.41, 69.47, and 67.55% inhibition, respectively. This study demonstrates the potential of Maranhão Bacillus spp. isolates for use as biological fungal-control agents. Made available in DSpace on 2017-12-27T23:19:35Z (GMT). No. of bitstreams: 1 CNPAF2017ajar.pdf: 352702 bytes, checksum: 563e229ac5c3d4e9ba913fa9e87dd9d8 (MD5) Previous issue date: 2017-12-27

RESUMO O objetivo deste trabalho foi avaliar o efeito da aplicação de silicato de cálcio e de cinza de casca de arroz (CCA) na incidência de fungos associados a manchas em sementes de arroz irrigado. Plantas de arroz foram submetidas à aplicação de silicato de cálcio ou CCA nas doses de 0, 51, 153, 256 e 357 kg ha-1de silício (Si). Dois experimentos foram conduzidos, sendo um na safra 2007/2008 e outro na safra 2008/2009 e, posteriormente, amostras de sementes foram analisadas em laboratório. Foram realizadas avaliações do Índice de Escurecimento de Sementes (IES), da concentração de Si no pericarpo das sementes e a determinação da diversidade dos fungos presentes nas sementes. Não houve efeito das duas fontes de Si empregadas, nas doses utilizadas nos dois experimentos no IES e na concentração de Si. Os fungos fitopatogênicos encontrados em ambos experimentos foram Alternaria padwickiii, Bipolarisoryzae, Botrytis cinerea, Curvularia lunata, Fusarium semitectum, F. solani, Microdochium oryzae, Nigrospora oryzae, Phoma sorghina e Pyriculariaoryzae. A incidência destes fungos não foi afetada pela aplicação das fontes de Si nas doses utilizadas. ABSTRACT The aim of this study was to evaluate the effect of calcium silicate and rice husk ash (CCA) application on the incidence of fungi associated with spots in flooded rice seeds. Rice plants were subjected to application of calcium silicate or CCA at the levels of 0, 51, 153, 256 and 357 kg ha-1 of silicon (Si). Two experiments were performed, one in the 2007/2008 crop season and another one in the 2008/2009 season; subsequently, seed samples were analyzed in laboratory. Evaluations were performed for Seed Browning Index (IES), Si concentration in the pericarp of the seeds and determination of the diversity of seedborne fungi. There was no effect of the two employed Si sources at the used levels in both experiments, for IES and Si concentration. The phytopathogenic fungi found in both experiments were Alternaria padwickiii, Bipolaris oryzae, Botrytis cinerea, Curvularia lunata, Fusarium semitectum, F. solani, Microdochium oryzae, Nigrospora oryzae, Phoma sorghina and Pyricularia oryzae. The incidence of these fungi was not affected by the application of Si sources at the used levels.

The use of beneficial microorganisms in forage grasses is a potentially advantageous technique for a more sustainable pasture management by decreasing the need for chemical fertilization. Our aims were to determine the best method of microorganism inoculation on Brachiaria (Syn. Urochloa) brizantha cv. BRS Piata, compare the responses of inoculated plants of this forage grass with fertilized and unfertilized controls and examine its effect on some morphological, physiological and biochemical responses. On the first experiment, three inoculation methods were tested: in the seed, seed and soil, and soil, with Pseudomonas fluorescens (BRM-32111) and Burkholderia pyrrocinia (BRM-32113). In the second experiment, fertilized and unfertilized plants were either inoculated with BRM-32111, BRM-32113 and co-inoculated (BRM-32111 + BRM-32113). In a final experiment, B. brizantha was inoculated by soil drenching with BRM-32111, BRM-32113 and co-inoculated (BRM-32111 + BRM-32113), and compared to fertilized- and unfertilized-controls. The inoculation by soil drenching, at seedling stage, was more effective than inoculation only in the seed or both in the seed and by soil drenching. The fertilizer may have suppressed the beneficial bacterial effects on the growth of B. brizantha. P. fluorescens and B. pyrrocinia co-inoculated increased nitrate, protein, nitrogen concentration, Spad index (chlorophyll content), leaf area, number of tillers, net photosynthesis and total biomass production of B. brizantha plants. Our results point out to a potentially valuable source of practical information in the search of an eco-friendlier approach to increase pasture productivity. Made available in DSpace on 2018-01-26T23:46:53Z (GMT). No. of bitstreams: 1 AJPS2018012510452186.pdf: 1289010 bytes, checksum: 5a999b6e875b09fd432c3def206c9d03 (MD5) Previous issue date: 2018-01-26

Plant growth promoting rhizobacteria (PGPR) are a specific group of bacteria interacting beneficially with plants. Among the known PGPRs, the species Pseudomonas fluorescens and Burkholderia pyrrocinia have been highlighted in both growth promotion and control of rice diseases. Ensuring the stability of the microorganism during production, formulation, distribution and storage has been a challenge for these species. In this context, the objective of this work was to develop liquid formulations, through a simplified process, that allows increase in the shelf life of these rhizobacteria for commercial application. Both bacteria were tested in 32 formulations under two storage temperature conditions: 8 and 28°C, resulting in 64 treatments for each species, which were evaluated for 180 days. Combinations of the adjuvants: molasses, glycerol, NaCl, PVP, MgSO4, K2HPO4 and yeast extract were evaluated. Formulations containing molasses, stored at 8°C, were considered the most efficient in maintaining microbial viability. The method used was considered efficient to select three formulations that allowed maintenance of the concentration of viable cells of P. fluorescens and B. pyrrocinia in 108 cfu.mL-1, for at least 90 and 150 days, respectively, not interfering with bacterial action potential. Made available in DSpace on 2018-03-29T00:36:15Z (GMT). No. of bitstreams: 1 CNPAF2018ajmr.pdf: 601726 bytes, checksum: 5970745b4e67a559f82e02cbd6492e9c (MD5) Previous issue date: 2018-03-28

The integrated management of rice leaf blast (Magnaporthe oryzae) is carried out mainly with the adoption of chemical control. However, the search for alternative practices has grown in recent years. Thus, the variability of 28 Sarocladium oryzae isolates was evaluated for the cerulenin production, as well as its potential for reducing the severity of rice leaf blast, quantifying the activity of enzymes linked to the plant defense mechanisms. More than 55 % of the S. oryzae isolates were antagonistic to the pathogens M. oryzae, Cochliobolus miyabeanus, Thanatephorus cucumeris and Monographella albescens, and 60 % of the isolates produced cerulenin at detectable levels. Both BRM 6461 (296.0 µg mL-1) and BRM 6493 (undetectable cerulenin) inhibited the formation of M. oryzae appressoria in 89.5 % and 85 %, respectively. The BRM 6461 isolate, applied as conidial suspension and filtered, reduced the severity of rice leaf blast in 68.8 % and 75.5 %, respectively. The enzymatic activity in the presence of M. oryzae was higher for lipoxygenase at 5 h (filtered) and at 24 h and 72 h (conidial suspension) after the pathogen inoculation. For phenylalanine ammonia lyase, the highest expression was at 5 h (filtered) and 72 h (conidial suspension). The enzymes chitinase, β-1,3-glucanase and peroxidase and the salicylic acid phytohormone presented no differences, in relation to the controls (water and M. oryzae). The filtered from the BRM 6461 isolate, basically constituted by cerulenin, reduced the severity of rice leaf blast and possibly activated the defense mechanisms of the rice plants against M. oryzae. RESUMO O manejo integrado de brusone (Magnaporthe oryzae) em arroz é realizado, principalmente, com a adoção de controle químico. No entanto, a busca por práticas alternativas tem crescido nos últimos anos. Assim, avaliou-se a variabilidade de 28 isolados de Sarocladium oryzae, quanto à produção de cerulenina, e o seu potencial na redução da severidade de brusone foliar em arroz, quantificando-se a atividade de enzimas ligadas ao mecanismo de defesa das plantas. Mais de 55 % dos isolados de S. oryzae foram antagônicos aos patógenos M. oryzae, Cochliobolus miyabeanus, Thanatephorus cucumeris e Monographella albescens, e 60 % dos isolados produziram cerulenina em níveis detectáveis. Tanto BRM 6461 (296,0 µg mL-1) quanto BRM 6493 (cerulenina não detectável) inibiram a formação de apressórios de M. oryzae em 89,5 % e 85 %, respectivamente. O isolado BRM 6461, aplicado na forma de suspensão de conídios e filtrado, reduziu a severidade da brusone em 68,8 % e 75,5 %, respectivamente. A atividade enzimática, na presença de M. oryzae, foi maior para lipoxigenase após 5 h (filtrado) e 24 h e 72 h (suspensão de conídios) da inoculação do patógeno. Para fenilalanina-amônia liase, a maior expressão ocorreu após 5 h (filtrado) e 72 h (suspensão de conídios). As enzimas quitinase, β-1,3-glucanase e peroxidase e o fitohormônio ácido salicílico não apresentaram diferenças em relação aos controles (água e M. oryzae). O filtrado do isolado BRM 6461, constituído basicamente por cerulenina, reduziu a severidade da brusone e, possivelmente, ativou os mecanismos de defesa da planta de arroz contra M. oryzae.

We explored furanocoumarin compounds extracted from herb Ruta graveolens to suppress the blast rice disease by eliciting rice systemic resistance pathways. The plant material was subjected to the extraction method by percolation with 80% hydroethanolic solution, which allowed the obtaining of the furanocoumarins, that were monitored by HPLC.Tests were carried out in vitro and in greenhouse. The experimental design was entirely randomized with 24 treatments and 3 replicates.The concentration of 6.75 mg/mL of extract providedthe highest chitinase activity in the period of 24 and 48 hours before inoculation with the pathogen, with the latter referring to 2.67 and 2.70 mg of glic.h -1.mg prot-1, respectively, for chitinase and 6.04 and 7.84 mg of gly.h -1.mg prot-1, respectively for β-1,3-glucanase.The concentrations of 0.7 mg/mL psoralen and 1.2 mg/mL bergapten strongly induced the defense mechanisms of rice plants translating in substantial reduction of disease severity in more than 90%.These results underscore the potential application of a plant extract containing furanocoumarins to mitigate the bursting burden of rice by increasing the mechanisms of systemic resistance. The use of plant extracts allows the reduction of the disease through several different mechanisms, which makes this strategy very efficient and innovative. Made available in DSpace on 2017-12-27T23:19:47Z (GMT). No. of bitstreams: 1 CNPAF2017ijrsb.pdf: 414061 bytes, checksum: 96a3a31b4423c0210915e39093ed85a6 (MD5) Previous issue date: 2017-12-27

O objetivo do trabalho foi determinar a influência da presença ou ausência da aplicação de fungicidas, e dos manejos de nitrogênio, com base no uso do clorofilômetro e de acordo com a recomendação local, na produtividade de grãos e nas características agronômicas das cultivares BRS Tropical e Epagri 109 de arroz irrigado, em várzea tropical. A pesquisa foi conduzida em um Gleissolo Háplico distrófico de várzea, por dois anos consecutivos. O delineamento experimental usado foi o de blocos casualizados, com quatro repetições, no esquema de parcelas divididas constituídas pelas aplicações de fungicidas, as subparcelas, pelas cultivares e, as subsubparcelas, pelos manejos de nitrogênio. A adubação nitrogenada com base no uso do clorofilômetro é realizada nos momentos de maior demanda do nutriente pelas plantas e, na ausência de fungicidas, propicia aumento na produtividade de grãos e na eficiência de uso de nitrogênio. Esse manejo de nitrogênio associado com a aplicação de fungicidas promove melhoria no perfilhamento e no rendimento industrial de grãos. A necessidade da aplicação de fungicidas em arroz irrigado é maior quando a adubação nitrogenada em cobertura é efetuada tardiamente em épocas pré-determinadas de acordo com as recomendações tradicionais. Made available in DSpace on 2017-12-14T23:24:08Z (GMT). No. of bitstreams: 1 CNPAF2017rbas.pdf: 57508 bytes, checksum: c55c46f678520ab1a4db652e434cf5cc (MD5) Previous issue date: 2017-12-14

Blast, caused by the fungus Pyricularia oryzae, is an important disease affecting rice and wheat yield worldwide. This study investigated the cytological aspects of incompatible (non-host resistance) and compatible (host resistance) rice- (R_Po) and wheat- (W_Po) Pyricularia oryzae isolate interactions. Inoculations of rice and wheat with the R_Po and W_Po isolates of P. oryzae, respectively, were expected to be compatible interactions (host resistance), whereas inoculations of rice and wheat with the W_Po and R_Po isolates of P. oryzae, respectively, were considered to be incompatible interactions (non-host resistance). For the compatible interactions (rice-R_Po and wheat-W_Po), fungal hyphae penetrated and colonized the epidermal cells and also invaded many neighboring cells. By contrast, in the case of the incompatible interactions (rice-W_Po and wheat-R_Po), fungal hyphae were not able to penetrate nor colonize the epidermal cells, but when penetration did occur, the hyphae were restricted to the first-invaded epidermal cell. The frequency of appressorial sites exhibiting infection hyphae within the epidermal cell underlying an appressorium was greater in the case of the compatible interactions. By contrast, unsuccessful penetrations with cytoplasmic granulation occurred with high frequency in the incompatible wheat-R_Po and rice-W_Po interactions and the number of necrotic epidermal cells underlying the appressorium was low for the rice-W_Po interaction as well as for the wheat- R_Po interaction, where no symptoms of necrosis were exhibited. However, the opposite was observed for the compatible interactions. The present study presents cytological features associated with incompatible and compatible rice- and wheat-P. oryzae interactions that may be useful to studies involving variability, coevolution, diagnosis, and regulation of quarantine or even in a rice or wheat breeding program whose aim is to transfer genes involved in non-host resistance to host resistance due to similarities in downstream mechanisms.

Better understanding of the use of cover crops at no-tillage systems in upland rice crop could contribute to increase grain production in this environment and allow moving toward sustainable agriculture. The objective of this research was to determine the effect of pearl millet intercropped with other cover crops on N mineral forms and urease activity in the soil, nitrate reductase enzyme activity in the leaves and yield components and grain yield of upland rice. The experiment was performed in the year 2012/2013 in two locations, in Haplorthox soil under no-tillage system. The experimental design was a complete randomized block with eight replications. The treatments consisted of four types of cover crop [(1) Pearl millet (Pennisetum glaucum) - control; (2) Pearl millet + Crotalaria spectabilis; (3) Pearl millet + Brachiaria ruziziensis; (4) Pearl millet + C. spectabilis + B. ruziziensis]. The mixture of cover crops pearl millet + C. spectabilis allowed the highest levels of nitrate in the soil. The cover crops pearl millet, pearl millet + C. spectabilis, pearl millet + Brachiaria ruziziensis, and pearl millet + C. spectabilis + Brachiaria ruziziensis provided similar results for ammonium content and urease activity in the soil, nitrate reductase activity in leaves, yield components and grain yield of upland rice grown under no-tillage. Our results allow inferring that the use of pearl millet, as cover crop, alone or intercropped with B. ruziziensis or C. spectabilis is a management practice option to provide high rice grain yield.

Phytoalexins are compounds that have been studied a few years ago, which present mainly antimicrobial activity. The plants of the family Poaceae are the most geographically widespread and stand out for their economic importance, once they are cereals used as staple food. This family stands out for having a variety of phytoalexins, which can be synthesized via the shikimic acid (the phenylpropanoids), or mevalonic acid, being considered terpenoid phytoalexins. The characterization of these compounds with antimicrobial activity is carried out using chromatographic techniques, and the high-performance liquid chromatography (HPLC) coupled with mass spectrometry are the most efficient methods in this process. This research aimed to present an approach of the function, characterization and biosynthesis of phytoalexins in plants of the family Poaceae. RESUMO: As fitoalexinas são compostos que vêm sendo estudados há alguns anos, apresentando principalmente atividade antimicrobiana. As plantas da família Poaceae são as geograficamente mais difundidas e se destacam por sua importância econômica, uma vez que são os cereais que compõe a base da alimentação, em todos os continentes. Essa família se destaca por apresentar uma variedade de fitoalexinas, sendo que as mais importantes são sintetizadas a partir da via do ácido chiquímico. A caracterização desses compostos com atividade antimicrobiana é realizada por meio de técnicas cromatográficas, sendo que a cromatografia líquida de alta eficiência (HPLC) acoplada com espectrometria de massas é a técnica mais eficiente nesse processo. O trabalho apresenta como objetivo uma abordagem da função, caracterização, biossíntese e aplicações das fitoalexinas em plantas da família Poaceae.

Blast, caused by the fungus Magnapor the oryzae, is one of the most widespread diseases affecting the rice crop. The use of fungicides to combat phyto pathogenic fungi causes great environmental problems. Plant extracts have been studied as an alternative method of plant pathogen control. Ruta graveolens has compounds with antifungal activity, such as furanocoumarins. The objective of this study was to test the effects of various concentrations of the standardised plant extract of R. graveolens as well as its fractions and furanocoumarins (psoralen and bergapten) on reducing M. oryzaemycelial growth. The aerial part of R. graveolens was grinded and subjected to a characterisation process, percolation, concentration, and furanocoumarin standardisation. The standardised extract was fractionated and the fractions were subjected to high-performance liquid chromatography (HPLC) to quantify furanocoumarins. The effects of the extract, fractions, and standards against mycelial growth ofM.oryzaewere tested in vitro. The plant material was handled in accordance with the guidelines established by the general methods of the Brazilian Pharmacopoeia. The furanocoumarin content was the highest in the ethyl acetate fraction. The best results for the mycelial growth test were observed using the extract and the hexane and ethyl acetate fractions. The standardised herbal extract of R. graveolens showed antifungal activity against M.oryzae.

The effects of silicon fertilization and bioagents in suppressing leaf blast were studied in two greenhouse experiments using a susceptible upland rice cultivar, BRS Primavera. In the first experiment, the treatments consisted of four doses of SiCaMg (1,2,4 and 8 tons Si.ha-1) and four bioagent (Burkholderia pyrrocinia (Bp); Pseudomonas fluorescens (Pf); Trichoderma asperellum (Ta) and a mixture of the three bioagents (Bp+Pf+Ta), in addition to untreated controls. The most effective treatment was silicon fertilization at 2tons in combination with the three bioagents, which reduced leaf blast by 96%. A second experiment was conducted to study the defense mechanism involved in disease suppression. The treatments were organized in a randomized block design, with or without Si (0 or 2 tons Si) and bioagents (non-inoculated control, Ta or Bp+Pf+Ta). The combination of silicon fertilization (2 tons SiCaMg.ha-1) with T. asperellum or with a mixture of the three bioagents increased the activities of chitinase (CHI), β-1,3glucanase (GLU), peroxidase (POX) and phenylalanine ammonia-lyase (PAL) as well as the salicylic acid (SA) content in rice plants in the absence of the pathogen Magnaporthe oryzae. The mixture of the three bioagents in plants fertilized with 2 tons Si increased GLU enzyme activity and SA levels at 24 and 48 hours after infection of the plants challenged with M. oryzae. The activation of defense mechanism by combination of silicon fertilization with bioagent mixture could be an effective strategy for rice blast management.

The objective of this work was to purify and standardize the rue (Ruta graveolens) extract and evaluate its effect on Magnaporthe oryzae as an alternative to the integrated management of rice blast. The drug was characterized, the liquid extract was obtained, and the methodology for quantifying the standard markers psoralen and bergapten was validated. Rue extract and the markers, solely or in combination, were assayed in vitro, as well as in greenhouse conditions, for their ability to suppress leaf blast, by the evaluation of mycelial growth, conidial germination, and appressorium formation. Rue extract inhibited M. oryzae mycelial growth (100%), conidial germination (LD50=0.237 mg), and the appressorium formation (LD50=0.121 mg); besides, the extract reduced leaf blast severity by 80.84%. Fluorescence microscopy showed that rue extract did not damage M. oryzae cell wall and plasma membrane, indicating another mode of action. Rue extract has a great potential for controlling rice leaf blast. Resumo: O objetivo deste trabalho foi purificar e padronizar o extrato de arruda (Ruta graveolens) e avaliar o seu efeito sobre Magnaporthe oryzae como alternativa para a gestão integrada da brusone. A droga vegetal foi caracterizada, o extrato líquido obtido, e a metodologia para quantificar os marcadores padrão psoraleno e bergapteno validada. O extrato de arruda e os marcadores, isolados ou combinados, foram ensaiados in vitro, assim como em condições de casa de vegetação, para a avaliação de sua capacidade de suprimir a brusone, pela avaliação do crescimento micelial, da germinação de conídios e da formação de apressório. O extrato de arruda inibiu o crescimento micelial de M. oryzae (100%), a germinação de conídios (DL50=0,237 mg) e a formação de apressórios (DL50=0,121 mg); além disso, o extrato reduziu a severidade da brusone em 80,84%. A microscopia de fluorescência mostrou que o extrato de arruda não danificou a parede celular e a membrana plasmática de M. oryzae, o que indica outro modo de ação. O extrato de arruda apresenta grande potencial para o controle da brusone em folhas de arroz.

Diversas gramíneas que ocorrem em lavouras de arroz apresentam sintomas do mal-do-pé, causado por Gaeumannomyces graminis var. graminis (Ggg), em condições naturais de infecção. Com o objetivo de obter informações sobre hospedeiros e resistência de genótipos de arroz ao mal-do-pé, foi estudada a patogenicidade do isolado Ggg-a 01, coletado de arroz, em sete espécies de capim e oito de cereais, em casa-de-vegetação. Os testes de inoculação mostraram que o isolado de arroz foi patogênico às plantas daninhas de capim arroz (Echinochloa crusgalli), avião (Pennisetum setosum), braquiária (Brachiaria sp.), digitária (Digitaria horizontalis), marmelada (Brachiaria plantaginea), pé-de-galinha (Eleusine indica) e timbete (Cenchrus echinatus) e que essas espécies constituem hospedeiros potenciais do patógeno. Cereais de inverno, como o trigo, aveia, centeio, cevada e triticale, bem como o sorgo, milho e milheto, apresentaram diferentes graus de suscetibilidade ao isolado Ggg-a 01. As diferenças foram significativas, quanto à altura da lesão e à produção de hifopódios e de peritécios nos colmos. Não foram observados peritécios em milheto, sorgo, timbete e milho. A resistência de 58 genótipos de arroz de terras altas ao isolado foi avaliada e os genótipos SCIA16 e SCIA08 apresentaram altura de lesão significativamente menor, sendo considerados resistentes, em relação ao genótipo CNAS10351, altamente suscetível.

Rice blast (Magnaporthe oryzae) disease can cause losses of up to 100% in grain production. A sustainable management should consider alternative control measures. In the present work, biotic resistance induction to blast disease was studied by comparing disease severity and quantifying some pathogenesis-related proteins (PRPs). Rice plants of cultivars Metica-1 and Cica-8 were sprayed with biotic resistance inducers (incompatible isolates of M. oryzae) 48 h before inoculation with challenging isolates (compatible isolates of M. oryzae) under greenhouse conditions. For both cultivars, Metica-1 and Cica-8, the area under the disease progress curve was reduced by more than 80% when plants were induced with avirulent isolates of Magnaporthe oryzae. The biotic inducers also promoted an increase in the activity of peroxidase (POX), β-1.3-glucanase (GLU), chitinase (CHI), and phenylalanine ammonia-lyase (PAL). Systemic expression of resistance was also observed.

The goal of the present study was to characterize anatomical and biochemical changes in rice plant roots in response to seed treatment with rhizobacteria (Burkholderia pyrrocinia(R-46) +Pseudomonas fluorescens(R-55)) andTrichoderma asperellum(Ta: mixture of strains T-06, T-09, T-12, and T-52). The experimental design was completely randomized, with six treatments (R-46, R-55, R-46 + R-55, Ta+ R-46 + R-55, Ta, and control) and ten replicates. Treatments Ta and R-46 + R-55 increased the root length and diameter as well as the cortex expansion and induced a 2% expansion of the aerenchymal space. Treatments Ta and R-46 increased the vascular cylinder diameter. The number of protoxylem poles and metaxylem vessel elements was increased by R-46 and R-55. The total phenol content increased with treatments Ta, R-46 + R-55, R-46, and R-55, and all the treatments increased the flavonoid content. The lignin content increased with the Ta and R-55 treatments. All the root architecture modifications resulting from the interaction between seedlings and bioagents (rhizobacteria andTrichodermaspp.) observed in the present study favored the root plasticity of rice seedlings.

Crude extract of an isolate of the fungus Sarocladium oryzae (CNPAF So 20G), containing the antimicrobial cerulenin, was produced and its antagonistic potential on the rice blast pathogen Magnaporthe oryzae was asessed. Cerulenin was detected in crude extract of S. oryzae through thin layer chromatography showing a Rf value of 0.63. The quantity of cerulenin in the crude extract was 237 µg.mL-1. The in vitro inhibition of germination and appressorial formation of M. oryzae was assessed on an artificial hydrophobic surface, using eight different doses of cerulenin ranging from 0.05 to 30.0 µg.mL-1. The LD50 values calculated based on the Probit-log analysis for germination and appressorial formation were 1.298 ± 0.123 µg.mL-1 and 0.0705 ± 0.0062 µg.mL-1 of cerulenin, respectively. The 30.0 µg.mL-1 of cerulenin dose inhibited 98% and 99%, germination and appressorial formation, respectively. The mode of action of cerulenin was studied by staining conidia with Calcofluor White and fluorescent microscopy showing its effect on plasma membrane. Crude extract of S. oryzae suppressed 63% of rice blast disease in greenhouse conditions. The results indicate that a product based on cerulenin and/or S. oryzae has a great potential to be used in biological control of rice blast. Made available in DSpace on 2018-01-18T22:18:26Z (GMT). No. of bitstreams: 1 CNPAF2104tpp.pdf: 2415682 bytes, checksum: 826d02dfac4c219510129dd2f6421b01 (MD5) Previous issue date: 2018-01-18

Panicle blast (Pyricularia grisea) in upland rice causes significant yield losses depending upon the environmental conditions and nutritional status of the plant at the grain-filling stage. Four field experiments were conducted to evaluate the influence of mineral nutrients on panicle blast of four upland rice genotypes on an oxisol. Panicle blast severities of four genotypes were related to nutrient concentrations in panicle tissues. Nitrogen (N), phosphorus (P), and magnesium (Mg) contents in tissue were significantly (P

Epicoccum sp. showed in vitro antagonism to the rice pathogens Magnaporthe oryzae, Rhizoctonia solani, Sarocladium oryzae, Monographella albescens and Cochliobolus miyabeanus in dual culture. The colony growth of the rice blast fungus, M. oryzae, was reduced by 42.50%. The lethal doses (LD50) determined based on probit-log dosage response curves at 3 and 6 hours after germination were 393.0 and 326.6 ppm, respectively. The crude extract (600 ppm) reduced appressorial formation by 95.68%. A greenhouse experiment comparing the relative efficiency of conidial suspension and crude extract of Epicoccum sp. in the suppression of leaf blast showed no statistical difference between both application methods. However, the crude extract of Epicoccum sp. (4000 ppm) 48 hours before the application of M. oryzae induced resistance and suppressed leaf blast by 97.6%. Scanning electron microscopy of rice leaves inoculated with crude extract of Epicoccum sp. and challenged with M. oryzae showed appressorial deformation on penetration phase. Peroxidase and β-1,3-glucanase activities increased in plants sprayed with crude extract of Epicoccum sp., 24 hours after the application of the challenger. PAL as well as chitinase activities increased 72 hours after challenge inoculation. Epicoccum sp. was shown to be a potential antagonist and inducer of resistance against M. oryzae.

A collection of Gaeumannomyces graminis var. graminis isolates obtained from symptomatic rice and grass plants in central and northern Brazil were studied in regard to pathogenicity on rice and cultural characteristics. For all isolates, only one type of lobed hyphopodia was observed both in the field and artificially inoculated plants. Perithecia were formed on artificial media and inoculated leaf sheaths. Hyphopodia were formed from ascosporic germ tubes. The hyphae under moist stress conditions produced dark brown chlamydospores that were initially hyaline. Large variation in the number of chlamydospores produced and duration of perithecia formation was observed among the isolates. Pathogenicity assays showed that 60-day old rice plants were more susceptible than 35-day old plants. The isolates from rice and grasses varied significantly in regard to disease severity on both rice seedlings and adult rice plants. In general, the isolates from rice were more aggressive than the isolates from grasses. Spontaneous infection of rice plants by ascosporic inoculum from perithecia on rice stubbles was observed in the greenhouse, suggesting their role as a source of primary inoculum in the field, which deserves further investigation.

O objetivo foi avaliar o efeito do silicato de cálcio e magnésio na produtividade do arroz em rotação com soja em sistema de plantio direto no estado do Maranhão. O experimento foi implantado em área do Sindicato Rural de Imperatriz - Parque de exposições. Inicialmente realizou-se coleta e análise de solos para fins de fertilidade. Após os resultados da análise de solo, aplicou-se agrosilício (silicato de cálcio e magnésio) e calcário para correção de acidez do solo. Passado trinta dias, microbiolizou-se 2,6 kg de sementes com rizobactérias promotoras de crescimento (Pseudomonas sp. e Burlkoderia sp.) e procedeu-se o plantio do arroz, em esquema experimental de blocos ao acaso com parcelas sub-subdivididas com quatro repetições com cinco tratamentos (0, 1, 2, 4, 8 t.ha-1 de silicato de cálcio e magnésio - Agrosilício). Os primeiros resultados foram coletados considerando a emergência e altura de plântulas, seguidas das avaliações de Produtividade, Biomassa e Massa de 100 grãos cheios. Segundo os dados analisados, as dosagens de agrosilício não obtiveram influência sobre o crescimento de plântulas, biomassa, massa de 100 grãos cheios e produtividade do arroz em sistema de plantio direto. Made available in DSpace on 2017-11-16T23:27:57Z (GMT). No. of bitstreams: 1 CNPAF2013ra.pdf: 145277 bytes, checksum: 6119864bc958ef69d692c47b7c8e7759 (MD5) Previous issue date: 2017-11-16

O Brasil é o oitavo produtor mundial de arroz. No Maranhão, o arroz é cultivado em consórcio com outras culturas, destacando-se o feijão e o milho, sendo pouco frequente o cultivo isolado. A cultura do arroz é afetada por diversos fatores, sendo as doenças fúngicas uma das principais responsáveis pela perda da produtividade. No entanto o agrosilício (silicato de cálcio, magnésio e silício) tem sido testado em diversos experimentos, pois o silício aumenta a resistência da planta. O presente trabalho objetivou analisar a resposta da planta ao agrosilício, considerando a incidência de doenças e estabelecer a dose mais eficiente de silicato de cálcio e magnésio para compor o manejo integrado de doenças do arroz, no estado do Maranhão. O experimento foi instalado nas dependências do Parque de Exposição de Imperatriz-MA, pertencente ao Sindicato Rural de Imperatriz, situado a BR 010, em uma área cultivada no ano anterior com soja (Glycine max (L.) Merrill). Em delineamento de blocos ao caso com parcelas subdivididas e quatro repetições, os cinco tratamentos são compostos pelas doses de silício (0, 1, 2, 4, 8 t/ha de silicato de cálcio e magnésio - Agrosilício). De acordo com os dados das análises estatísticas não houve diferença significativa entre nenhuma das dosagens de silício aplicadas para o controle das doenças: brusone nas folhas, brusone nas panículas, sendo necessária a condução de novos experimentos para indicar-se a melhor dosagem de agrosilício a ser aplicada ao solo para redução das doenças do arroz.

Seven sources of resistance to the two predominant races IB-1 and IB-9 of the rice blast pathogen Pyricularia grisea were selected based on leaf blast reaction in tests conducted under controlled greenhouse conditions. Crosses involving resistant and susceptible parents were made to study the inheritance of the disease reaction for different sources of resistance. The F1 and F2 progenies of all crosses, including backcrosses to resistant and susceptible parents, were tested for reaction to leaf blast. The data showed that resistance is controlled by one to three genes that segregate independently in most of the donors. Non-allelic interaction among resistance genes, including dominant epistasis, was identified. Made available in DSpace on 2013-03-20T23:30:37Z (GMT). No. of bitstreams: 1 AP1996.002.pdf: 394348 bytes, checksum: 0699ef9c827c408547285641e4914e22 (MD5) Previous issue date: 1999-12-09

This study was carried out to select Trichoderma isolates from Amazon forest soil samples, identify their potential for sheath blight (Rhizoctonia solani) suppression in rice, and promote plant growth. Four out of the 13 isolates (T.06, T.09, T.12, T.52) which showed in vitro potential were evaluated through assays under greenhouse conditions utilizing four application methods: 1) preventive and curative sprays; 2) seed treatment + curative sprays; 3) seed treatment; 4) substrate treatment. These four isolates also showed reduced R. solani mycelial growth and sclerotial viability (>50%) and were positive for phosphate solubilization and cellulose degradation. They significantly reduced sheath blight severity when applied as seed treatment, substrate incorporation or foliar spray. However, the preventive and curative sprays were the most efficient method, reducing sheath blight severity by 43% and the area under the disease progress curve by 45%. Isolates T.12 and T.52 applied in substrate treatment increased aerial and root dry weight by 61.2 and 32.9%, respectively. These two isolates showed potential as growth stimulants and can be used as novel biological products and bioinoculants in agriculture for increasing grain yield. Made available in DSpace on 2019-11-18T18:09:05Z (GMT). No. of bitstreams: 1 CNPAF2012rca.pdf: 656038 bytes, checksum: 82ce26feab3052703cefd69426cc057c (MD5) Previous issue date: 2012

The rice cultivar Cica-8 exhibit differential reaction to several pathotypes of Magnaporthe oryzae. The objective of the present investigation was to determine the number of alleles involved in the expression of resistance to leaf blast and identify microsatellite markers linked to these alleles. A cross between cultivar Metica-1 and Cica-8 susceptible and resistant, respectively, to pathotype IB-1 (Py1049) was made to obtain F1, F2, BC1:1 and BC1:2 progenies. Greenhouse tests for leaf blast reaction showed that resistance is controlled by a monogenic dominant gene. For testing microsatellite markers, DNA of both resistant and susceptible parents and F1 and F2 populations was extracted. As expected for single dominant gene the F2 populations segregated at a ratio of 3:1. Of the 11 microsatellite markers tested, one marker RM 7102 was found to be closely linked to the resistant allele at a distance of 2.7 cM, in the cultivar Cica-8 to pathotype IB-1.

A brusone (Magnaporthe oryzae) é um dos principais fatores limitantes da produtividade do arroz de terras altas no Brasil. A época de plantio e o nível de adubação nitrogenada determinam o grau de severidade da brusone nas panículas. Foi realizado um experimento de campo com a cultivar BRS Bonança, visando determinar a relação entre o conteúdo de clorofila nas folhas superiores e a severidade de brusone nas panículas. O delineamento experimental foi blocos ao acaso em esquema de parcelas subdivididas com três repetições. Os tratamentos consistiram de 12 épocas de plantios em intervalos semanais e cinco níveis de nitrogênio (0, 30, 60, 120 e 240 kg ha-1 de N). As leituras do teor de clorofila foram feitas na folha bandeira com um clorofilômetro. A brusone nas panículas aumentou significativamente com o aumento dos níveis de N. Houve correlação significativa e positiva entre os níveis de N e o conteúdo de clorofila na folha bandeira (r=0,98; p ≤ 0,01). A relação entre a severidade de brusone nas panículas e o teor de clorofila foi linear e positiva (r= 0,99; p ≤ 0,01). Estes resultados mostram que o teor de clorofila pode ser incluído como variável independente no desenvolvimento de modelo matemático para a previsão de brusone nas panículas.

A brusone em arroz de terras altas causa danos significativos, necessitando de uma a duas aplicações de fungicidas, para o controle da doença. No entanto, o efeito de fungicidas sobre fungos não alvos do filoplano do arroz e benéficos são desconhecidos. Este trabalho objetivou avaliar o efeito de fungicidas no controle da brusone nas panículas, sobre fungos não alvos do filoplano de arroz, e estudar a antibiose de fungos não alvos para M. oryzae. Foi realizado um experimento em campo, utilizando-se duas cultivares (Primavera e Bonança), quatro fungicidas (trifloxistrobina + propiconazol, azoxistrobina, tebuconazol e triciclazol) e testemunha, com delineamento experimental em blocos ao acaso, em esquema de parcelas subdivididas, e quatro repetições. Foram avaliados a severidade da brusone nas panículas, o teor de clorofila nas folhas, o número de unidades formadoras de colônia cm-² de folha e a antibiose. A cultivar Primavera apresentou maior severidade de brusone nas panículas do que a Bonança. Os fungicidas azoxistrobina e trifloxistrobina + propiconazol diferiram significativamente da testemunha, com menores severidades de brusone nas panículas. O teor de clorofila não foi influenciado pelo tratamento com fungicida, mas houve diferença entre as cultivares. Os fungicidas tebuconazol, trifloxistrobina + propiconazol e azoxistrobina reduziram significativamente os fungos do filoplano, em relação à testemunha. O triciclazol proporcionou maior número de unidades formadoras de colônia cm-² de folha, não diferindo da testemunha. Dos quatro fungos testados, apenas Epicoccum sp. apresentou antagonismo para M. oryzae.

Eight additional rice cultivars as differentials were selected to identify pathotypes occurring in the Tocantins State. They were BRS Jaburu, BRS Taim, BRS Biguá, BR IRGA-417, Epagri 109, Javaé, Metica-1 and Supremo. These differentials were used in addition to the international set to determine the pathogenic diversity of 193 Pyricularia oryzae isolates collected during 1994-2002 from irrigated rice cultivars. They were conserved in Pyricularia culture collection of Embrapa Rice and Bean Research center. From 193 P. oryzae isolates 38 pathotypes were identified based on leaf blast reactions of international set and 29 pathotypes based on these additional differentials. The predominant pathotypes (TI-1, TG-2, TD-15 and TF-2) were represented by 53% of the tested isolates. The major international pathotypes (IB-45, IB-41, II-1 and ID-13) were represented by 43% of the isolates tested. The virulence pattern of 28 isolates belonging to the pathotype IB-45 was further differentiated into nine local pathotypes using additional set of differentials. The irrigated rice cultivars used as additional differentials serve as complementary set to identify pathotypes of interest for breeding blast resistant cultivars for Tocantins State.

A mancha de grãos (MG) ocupa o segundo lugar em importância econômica entre as doenças do arroz. Foi estudada a influência de níveis de adubação nitrogenada, época de plantio e concentração de esporos no ar sobre a severidade da doença no campo. A severidade de MG, na cultivar BRS Bonança, foi avaliada em duas épocas de plantio (30/11/2006 e 21/12/2006) e cinco doses de adubação nitrogenada (0, 30, 60, 120 e 240 kg de N.ha -1) utilizando o delineamento experimental de blocos ao acaso em esquema de parcelas subdivididas com três repetições. O efeito de dose de N sobre a severidade de MG não foi significativo. A correlação entre a severidade de MG e espiguetas vazias foi positiva e significativa. A população de fungos no ar (aerosporos) foi quantificada utilizando armadilhas volumétricas, Rotorod Sampler, desde a emissão até o amadurecimento das panículas. A mancha de grãos aumentou linearmente com tempo (r = 0,98; P

Genetic and phenotypic structure of Magnaporthe oryzae populations of two upland rice cultivars was determined. Monoconidial isolates were obtained from rice blast affected fields, four from cv. BRS Bonança and four from cv. Primavera, in Goias State (2001-2003). The pathotypes IB-41 and IB-9 were predominant in both leaf and panicle isolates of BRS Bonança and IF-1 in Primavera. A great majority of pathotypes were common to both leaf and panicle subpopulations of Bonança (42.8%) and Primavera (66.6%). The ANOVA of virulence data showed high variability within population of each cultivar. There was no significant difference in virulence pattern of isolates from leaves and panicles, independent of collection site and cultivar. The molecular characterization of isolates was done employing the rep-PCR analysis with two primer sequences from Pot2. The genetic analysis of 538 isolates showed a high genotypic diversity in both leaf and panicle pathogen populations with 103 haplotypes in Bonança and 49 in Primavera. The migration of pathotypes from leaves to panicles in each field was 70.8% and 36.6% for Primavera and BRS Bonança, respectively. The diversity of M. oryzae population was influenced by cultivar of origin. A great amount of population diversity was encountered within the same field. A estrutura genética e fenotípica da população de Magnaporthe oryzae foi estudada em folhas e panículas de duas cultivares de arroz de terras altas. Os isolados monospóricos foram obtidos em lavouras comerciais de arroz, quatro da cv. BRS Bonança e quatro da cv. Primavera, Goiás-Brasil (2001-2003). As raças IB-41 e IB-9 foram as predominantes entre os isolados de folhas e panículas de Bonança e a raça IF-1 para Primavera. De 35 e 27 raças identificadas de Bonança (42,8%) e Primavera (66,6%) foram comum a ambas as subpopulações de folha e panículas. Um total de 15 raças não encontradas em folhas foi detectado em baixa freqüência em panícula de Bonança. A anova da virulência, mostrou elevada variabilidade dentro de subpopulação de cada cultivar. Não existiu mudança significativa no padrão de virulência dos isolados de folhas e panículas, independente do local e cultivar. A caracterização molecular dos isolados foi realizada por Rep-PCR com dois primers da seqüência Pot 2. A análise genética dos 538 isolados mostrou elevada diversidade genotípica nas populações de folha e de panículas, com 103 perfis em Bonança e 49 em Primavera. A migração de raças de folhas para panículas em cada lavoura foi de 70,8% (Primavera) e 36,5% (Bonança). A maior parte da diversidade da população foi encontrada dentro de cada lavoura.

A resistência a doenças pode ser induzida em plantas tanto por agentes abióticos como por agentes bióticos, por exemplo isolados avirulentos de patógenos. No presente trabalho objetivou-se determinar a concentração de um isolado avirulento (indutor) e o período necessário para induzir resistência em folhas de arroz a um isolado virulento de M. oryzae. Em casa de vegetação, plantas com 18 dias das cultivares Metica-1 e Cica-8 foram pulverizadas com um isolado indutor de resistência, nas concentrações de 0, 105, 3x105 e 6x105 conídios.mL-1 em períodos que antecederam a inoculação do isolado virulento de 24, 48 e 72 horas. A indução da resistência manifestou-se na redução da área foliar afetada e no tipo de lesão. O grau de indução de resistência foi maior na cultivar Metica-1 do que na cultivar Cica-8, em relação a suas respectivas testemunhas. A indução da resistência em Cica-8 foi superior quando o indutor foi aplicado 48 horas antes da aplicação do isolado virulento nas concentrações de 6x105 e 3x105 conídios.mL-1. Por outro lado, a indução de resistência em Metica-1 foi significativamente maior em todas as concentrações e períodos de aplicações do indutor quando comparados com a testemunha, mas não houve diferença entre os tratamentos de indução. Made available in DSpace on 2022-04-14T12:00:21Z (GMT). No. of bitstreams: 1 fb-2007.pdf: 2233880 bytes, checksum: 2ae5021ba6117b8e93fa6e93d32c3801 (MD5) Previous issue date: 2007

O objetivo do presente trabalho foi caracterizar a virulência de populações de M. grisea provenientes das cultivares BRS Bonança e Primavera, utilizando as diferenciadoras japonesas e as NIL's das cultivares CO-39 e IAC-25.

O mal-do-pé em arroz (Oryza sativa) foi constatado em lavouras de terras altas nos municípios de Unaí (MG), Palmeiras (GO), Itaberaí (GO), Humaitá (AM) e em lavouras irrigadas nos Estados de Goiás, Tocantins e Rio Grande de Sul. O agente causal foi identificado como Gaeumannomyces graminis var. graminis baseado em características morfológicas, culturais e testes de patogenicidade utilizando diferentes isolados brasileiros. O método de inoculação e avaliação da doença em de casa de vegetação foi descrito. Este é o primeiro registro desta enfermidade na cultura do arroz no Brasil. Crown sheath rot also known as black sheath rot has been found to occur in upland rice (Oryza sativa) in the municipalities of Unaí (MG), Palmeiras(GO), Itaberaí (GO), Humaitá (AM) and in flooded rice in the States of Goiás, Tocantins and Rio Grande de Sul. The causal agent was identified as Gaeumannomyces graminis var. graminis based on morphological and cultural characteristics of the fungus as well as pathogenicity tests conducted utilizing different Brazilian isolates. This constitutes the first report of the disease occurrence in rice in Brazil.

Foram avaliados 39 híbridos de arroz (Oryza sativa) desenvolvidos a partir das linhagens 046I e IR 58025A com macho esterilidade genético citoplasmática derivado do citoplasma WA e seus restauradores, para resistência vertical a Pyricularia grisea. Os testes foram realizados em viveiro de brusone e em condições artificiais de inoculação com dois patotipos, em casa de vegetação. Em viveiro de brusone, todos os híbridos apresentaram reação suscetível variando de 5 a 9 em uma escala de 0 a 9. Reações compatíveis e incompatíveis à brusone nas folhas foram observadas para os dois patotipos IC-1 e IB-45, em inoculações controladas. A maioria dos híbridos foi resistente quando o restaurador utilizado como pai foi resistente. Entretanto, sete dos 25 híbridos F1 apresentaram reação suscetível mesmo quando um dos pais foi resistente para um patótipo. A resistência parcial de 11 híbridos e seus pais que apresentaram reação compatível foi analisada para resistência parcial. Foi observada interação diferencial entre isolados e genótipos para resistência parcial em relação a severidade e número de lesões esporulativas, indicando a natureza especifica da resistência parcial. Made available in DSpace on 2020-01-14T18:09:49Z (GMT). No. of bitstreams: 1 CNPAF2002fb2.pdf: 194195 bytes, checksum: 26e35f7d212ab8988ab3cb7bba3d4151 (MD5) Previous issue date: 2002