Rice is one of the world’s most consumed cereals, however, its production is affected by fungal diseases. Thus, the objective of this work was to evaluate the severity of diseases and grain yield potential of upland rice with silicon fertilization combined with seed microbiolization with Bacillus methylotrophicus isolates. Two experiments were conducted, one in Igarapé do Meio, Maranhão (MA), Brazil, with rice seeds of the variety Palha-Murcha and one in São Bento MA with rice seeds of the variety BRS-Primavera. A randomized block experimental design in a split-plot arrangement with five replications were used in both experiments, with agro-silicon rates (0.0, 1.0, 2.0, 4.0 and 6.0 Mg ha-1) in the plots and microbiolized and non-microbiolized rice seeds with B. Methylotrophicus at concentration of 108 CFU ml-1 in the subplots. The seedling emergence, grain yield, number of panicles, plant height, plant dry weight and severity of brown leafspot, leaf scald and grain spot were evaluated. Soil fertilization with agro-silicon affected positively the plant height of the variety Palha-Murcha and the number of panicles, plant dry weight and grain yield of the variety BRS-Primavera, and negatively the germination of the variety BRS-Primavera. Leaf scald severity in the variety BRS-Primavera reduced with microbiolized seeds with B. methylotropicus. Microbiolization with B. methylotropicus had no effect on severity of brown leafspot and grain spot in the varieties evaluated.
The seeds were microbiolized with the bacterial suspension in saline (0.85% NaCl) at a concentration of OD 540 = 0.5 AA and brought to a shaking table for 30 minutes. Seeds were plated on filter paper in experiments conducted in the laboratory with a completely randomized design with six treatments and five replications. We evaluated the incidence and reduction of pathogens in seeds. There was the assessment of healthy and infected seeds. The BRS Valiosa RR showed 48% of healthy seeds and 52% of infected seeds. According to the analysis of the incidence and control of pathogens in seeds with the use of Bacillus spp., the species Bacillus licheniformis and Bacillus pumilus showed the highest percentage rates of control in the range used in the experiment.
As sementes são componentes essenciais da economia, nelas está contida a vida e a possibilidade de disseminação de doenças, sendo a sanidade importante para o desenvolvimento sadio de plantas com altos rendimentos. O trabalho objetivou-se avaliar a qualidade sanitária de sementes de arroz da variedade Bonança e a redução de fitopatógenos, utilizando a microbiolização de sementes com Bacillus macerans, B. polymyxa, B. pentothenticus, B. lentus, B. pumilus, B. stearothermophilus e Bacillus sp.. A sanidade das sementes foi avaliada pelo método Blotter Test. A redução da incidência dos fitopatógenos nas sementes foi analisada por microbiolização para cada isolado e posteriormente, as sementes foram semeadas em solo esterilizado. O delineamento experimental utilizado foi o inteiramente casualizado nos experimentos em laboratório e em casa de vegetação. Avaliou-se a incidência e redução dos fitopatógenos em sementes e plantas de arroz aos sete e quatorze dias após a semeadura. As sementes foram avaliadas em lupa para identificar colônias de fungos. Quanto às plantas, em cada época retirou-se 100 plantas e realizou-se a assepsia usual. Os resultados do teste in vitro as sementes de arroz variedade Bonança, microbiolizadas com os Bacillus spp., reduziram a incidência de Curvularia oryzae e Aspergillus niger. Nas plantas originadas das sementes microbiolizadas com os Bacillus spp., observou-se a redução da incidência de Curvularia oryzae, Aspergillus niger e Scopulariopsis sp. A ação dos isolados foi diferenciada quanto ao patógeno e o tempo após a microbiolização das sementes.
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