Efeito do óleo de melaleuca na incidência de fungos e qualidade fisiológica em sementes de algodão

Abstract

Healthy seeds and the use of resistant cultivars have been effective strategies for controlling pathogens in cultivated species, with chemical control through seed treatment being the main strategy employed for seed health. However, various studies have shown that certain vegetable oils have an inhibitory effect on seed-transmitted fungi, representing potential alternatives to agrochemicals for seed health and/or better performance in cultivated species. The aim of this study was to evaluate the potential of melaleuca oil, which is popularly recognized for its antimicrobial properties, in controlling pathogenic fungi in cotton seeds, considering the species' susceptibility to a variety of seed-borne fungi. Untreated cotton seeds of the BRS Jade cultivar, along with those subjected to treatments with fungicide (Vitavax Thiram 200 SC) (20% Carboxin + 20% Thiram (w/v)) and different concentrations of melaleuca oil (Insitta) (0, 25, 50, 75, and 100% (v/v)), were analyzed for the incidence of pathogenic fungi, physiological quality, and initial development of the respective seedlings through the following laboratory tests and/or analyses: blotter test, seedling emergence in sand, first count of seedling emergence, seedling emergence speed index, seedling shoot length and dry mass, root system length and dry mass, and seedling dry mass. Based on the statistical analysis of the data by ANOVA and mean tests, it was observed that melaleuca oil was effective in controlling fungal infections in cotton seeds, with the 25% (v/v) dosage being the most efficient in controlling the fungi *Rhizopus stolonifer* and *Fusarium* sp., without causing immediate detrimental effects on seedling emergence, emergence speed, or initial seedling development after emergence.