Influência do sistema de produção de batata na supressividade do solo à murcha bacteriana

Abstract

Influence of the potato production system on soil suppressiveness to bacterial wil The potato crop (Solanum tuberosum L.) is the third most important source of human food in the world, after wheat and rice. In Brazil, it is the vegetable with largest area of growing and generates about 160 thousand direct and indirect jobs. The potato is affected by diseases transmitted by soil pathogens, causing the migration of the crop to areas never cultivated or without Solanaceaes from two to five consecutive years. The bacterial complex of Ralstonia spp., is one of the major diseases affecting the potato culture in the world. In Brazil, the conventional system of potato production, adopted in almost national conditions, promotes environmental conditions for the proliferation and development of the Ralstonia ssp. complex. In this way, alternative systems of production that reduce the incidence of bacterial wilt and decrease the intensity of the culture should be studied. Increased biodiversity and abundance of microorganisms in the soil is capable of suppressing an action of native soil pathogens. For this, management practices are applied that increase or decrease the production of soil extracts and of expression in bacteria in the alternative systems of production of potatoes, Paces and organic, were compared to conventional, unperturbed system in natural vegetation and sterilized soil. The experimental design was a randomized block design with three replications, in a 4 x 4 + 1 factorial scheme, the first factor represented the soils under different systems of production, while the second corresponded to the doses of 0.25,50 and 75% of soil contaminated with R. solanacearum added to each action. The additional was conventional soil with high incidence of R. solanacearum. It was concluded that a dose of 75% was the one that best represented a suppressiveness capacity of the soil to bacterial wilt in all the treatments, to the extent that the incidence of plants with wilt were for the treatments of autoclaved and conventional soil, that did not differ each other. The Paces System, was the one that had the greater potential of soil suppressiveness to the bacterial wilt in the potato. Keyword: Solanaceae; Alternative systems; Ralstonia solanacearum