1,151 research outputs found

    Phosphites for the control of anthracnose in common bean.

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    The objective of this work was to evaluate the effect of phosphites in the protection of common bean (Phaseolus vulgaris) against anthracnose. Different phosphite formulations were evaluated by quantifying peroxidase and polyphenol oxidase activity, total phenols, and lignin content. The treatments consisted of sprayings, in the V4, R5, and R7 stages, with: the K, Zn, Mn, K+Mn, K+salicyclic acid, and Cu phosphites; salicylic acid; acibenzolar-S-methyl; and the fungicide azoxystrobin; besides a control, without sprayings. The area under the disease progress curve was lower in plants that received applications of the K and Mn phosphites, whose values ranged between 74 and 81%, compared with the control. The K, Zn, and K+salicyilic acid phosphites were effective in controlling the disease. In addition, disease severity was lower with the application of the K, Zn, and Mn phosphites than with the control. Enzyme (peroxidases and polyphenol oxidases) activity and levels of soluble phenols were higher in common bean plants treated with the K and Mn phosphites, although no change was detected in the levels of soluble lignin in the same tissue. Phosphite application reduces the severity of the disease, can enhance enzymatic activity, and is an effective alternative for the control of anthracnose in common bean

    Severidade média da mancha angular do feijoeiro comum em ensaios de VCU no período de 2003-2009.

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    O objetivo deste trabalho foi estimar a severidade média da mancha angular em cultivares suscetíveis, em diferentes municípios, safras, e anos de cultivo

    Severidade média da mancha angular em ensaios de VCU no período 2003-2009.

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    O objetivo deste trabalho foi estimar a severidade média da mancha angular em cultivares suscetíveis, em diferentes municípios, safras, e anos de cultivo.Pôster - pós-graduação

    Impactos da precipitação mensal sobre a severidade da mancha angular e a produtividade do feijoeiro comum.

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    O objetivo deste estudo foi estimar perdas de rendimento causadas pela mancha angular, e os impactos da precipitação mensal sobre a doença e a produtividade no feijoeiro comum

    Impact of Supra-Optimal Temperatures on Physiology and Yield in Rice Field.

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    Heat stress is an increasing constraint for the productivity of rice (Oryza sativa L.) worldwide. In this context, a study was carry out to quantify the supra-optimal temperature effects on rice yield-components and secondly to investigate its effects on plant physiological attributes when different genetic backgrounds are submitted to contrasting environment air-temperatures during the anthesis, the most sensitive growth phase to heat stress. Three Embrapa's cultivars were used, BRS Pampa, BRS Sinuelo CL and IAS 12-9 Formosa which represent indica/japonica, indica and essentially japonica subspecies, respectively. One day before anthesis phase, sub plot plants were submitted to heat stress via polythene shelters for 96 h. Photosynthesis and respiration parameters were measured at 24 and 48 h after stress, and at physiological maturity, grain carbon isotope fractionation as well as yield components and grain yield were quantified. There were significant differences among genotypes for some gas exchange parameters at ambient and under increased temperatures at 24 and 48 h after stress, such as carbon assimilation and respiration rate. Heat-stress also affected yield components, especially for BRS Sinuelo CL showing the highest spikelet sterility (54%) while BRS Pampa had the lowest value (20.80%) and the highest 1000-grain weight and grain yield. These results demonstrate that although heat tolerance has been more frequently found in indica spp, this trait can also be present in genotypes combining indica/japonica genetic background, as shown by BRS Pampa cultivar.201

    Molecular studies of the brazilian infectious bronchitis virus isolates.

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    Avian infectious bronchitis virus (IBV) isolates have been widely characterized by reverse transcription followed by polymerase chain reaction and DNA sequencing. In present study, these techniques were applied to three viral genomic regions comprising the complete and/or a partial S1 segment, S2 and nucleocapsid genes. DNA sequences from viral isolates obtained from 1972 to 1989 and from 2006 to 2008 were compared. High similarity (>90%) was observed among some of the genomic segments, including S1 hypervariable region, which could suggest a common origin or ancestry. DNA sequences from S2 and N protein genes obtained from different infected tissues of the same flock were analyzed, and a clear segregation between respiratory and intestinal tract was observed. Therefore, these data suggest cocirculation of more than one viral strain in the same flock. 57.1% of DNA sequences from the S1 complete segment samples, 53.3% from the S2 fragment and 62.5% from the partial N gene were found to be different from analyzed sequences from reference strains leading to the conclusion that parte of viral isolates included in this study may be considered region specific. Considering the simultaneous analysis of the three genes, a large IBV genetic profile was observed in both old and recent isolates groups. However, most prominent diversity between viral isolates was obtained in the period from 1972 and 1989, showing the presence of a large number of variants in the state of Minas Gerais before the official approval of vaccination (1980)
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