Foto divulgaçãoPrelecionista: Gabriel Ferreira Paiva Data: 29/08/2022, às 14h, via Zoom*

Orientador: Frankin Jackson Machado

Resumo: Wheat is one of the most important cereal crops worldwide, but several fungal diseases can affect crop yield. Among them, Fusarium head blight (FHB), caused by members of the Fusarium graminearum species complex, is one of the most serious wheat diseases worldwide, causing a reduction in yield and grain quality due to the accumulation of mycotoxins. There are several strategies for FHB management, including cultural practices, sowing of resistant cultivars, chemical control, biological control, among others. The use of alternative products, such as chitosan and its derivatives, can be a viable alternative for disease control. The present study proposes to investigate the potential of chitosan oligosaccharide as an alternative, or in combination with chemical products, to reduce FHB intensity and reduce mycotoxin levels in wheat grains. The trials were carried out in the 2021 and 2022 winter seasons. The experiments were divided into in vitro tests, seed treatment and foliar application on wheat plants under greenhouse and field conditions. In the in vitro trials, it was possible to observe that the chitosan oligosaccharide had a direct effect on F. graminearum, depending on the concentration used. When applied in seed treatment, both tebuconazole and chitosan oligosaccharide reduced the incidence of F. graminearum and preserved the germination potential of seeds when inoculated with the fungus. In general, there was no significant reduction in disease severity between doses or times of chitosan oligosaccharide application in relation to the unsprayed check and the fungicide. However, it was possible to detect a direct correlation between the reduction of disease intensity, although not significant, with the reduction of the accumulation of DON in the grains. The results of this study suggest that chitosan oligosaccharide has the potential to be used as a tool in the integrated management of the disease, establishing a basis for future studies to explore the use of this product associated with chemical products, aiming to increase the efficacy of FHB control in wheat.

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