Bactérias biocontroladoras de manchas foliares e promotoras de crescimento de arroz: interações com cultivares, agrotóxicos e microbiota do solo.

Abstract

Some bacterial species may be used as biocontrol diseases and promoting plant growth. However, is known about their interaction with different rice cultivars, with pesticides and with the native soil microbial. Through the above objectives of this research were: i) to evaluate the effects of the interaction of bacterial iso lates with different rice cultivars in controlling brown spot, and promoting plant growth in the absence of the pathogen; ii) identify the mechanisms involved in biocontrol and promoting growth; iii) evaluate the behavior of bacterial isolates in the presence of pesticides used in irrigated rice; and iv) assess the impact of bacterial strains in soil on the native flora. The experiments were conducted in laboratory, greenhouse and field. We used bacterial strains: DFs185, DFs223, and DFs306 DFs416 individually or in combination, and 11 rice cultivars. The bacterial isolates behaved differently, varying the response of brown spot control according to cultivate and promote growth of rice plants. The BRS Querencia presented the best interaction with bacterial treatments, both for disease control and for promoting growth. Treatments that stood out for two purposes were DFs185 and DFs223, although all isolates have submitted at least one mechanism of action for the biocontrol and for growth promotion. All strains showed tolerance and / or resistance to different active ingredients used in rice cultivation, and positively changed soil quality. Thus, the isolates showed potential to be inserted in the integrated management of rice, performing the control functions of diseases and soil fertilization.