Tratamento sanitário de sementes de algodão, soja e pimentão com o gás ozônio

Abstract

Seed is one of the most important inputs in the implantation of a crop, but also can becom e one of the main ways of introduction and dissemination of phytopathogenic agents, mainly at long distances. Pathogens can be introduced into disease-free areas or increase the inoculum in areas that already have the pathogen through consecutive planting of infected seeds. The search for products that are more efficient and less phytotoxic to be used in seeds treatment it is an extremely important measure, especially in the organic production system. In this context, the aim in this work was to evaluate the efficiency of ozone gas in the control of fungi in cotton, soybean and pepper seeds, beyond evaluate the efficiency of their use in the physiological quality of seeds. Therefore, the thesis was divided in four chapters with cotton, soybean and pepper seeds. For this, the cotton seeds were inoculated with Colletotrichum gossypii var. cephalosporioids and submitted to the ozone in the concentrations of 25 g m -3 in periods of 0, 20, 40, 60 and 120 minutes; the two soybean cultivars were treated with ozone gas in concentrations of 15 and 25 g m -3 in periods of 0, 20, 40, 60 and 120 minutes and the lot of pepper seeds was submitted to the treatment with ozone in the concentration of 10 e 15 g m -³ in periods of 0, 20, 40, 60, 80 and 120 minutes. After the treatment of seeds with ozone, the following tests were done in all crops: sanity test, first count of germination, percentage of germination, seedling emergence, emergence speed index (ESI), initial stand, electric conductivity, accelerated aging test and tetrazolium test. Was also evaluated the activities of enzymes related to respiration and seeds deterioration. The treatment of cotton seeds in concentration of 25 g m -³ for 40 minutes was efficient in the control of pathogens Colletotrichum gossypii var. cephalosporioides, Aspegillus and Fusarium and at 60 minutes controlled the fungi Penicillium and did not affect the physiological and biochemical quality of seeds. For soybean, the sanitary treatment in the concentration of 15g m -³ for 20 minutes reduce the incidence of Alternaria, Aspergillus, Cercospora, Fusarium, Penicillium and Phomopsis fungis and did not affect the physiological and biochemical quality of seeds. The ozone gas in the concentrations of 10 and 15mg L -1 from 20 minutes was efficient in the fungi control of Alternaria sp., Penicillium sp., Aspergillus sp., Fusarium sp., Colletotrichum sp in pepper seeds.