Colonisation of arbuscular mycorrhiza and tolerance to Panama disease in seedlings of the maçã banana

Abstract

The aim of this study was to evaluate the effect of the colonization of arbuscular mycorrhiza on the tolerance to Panama disease of the banana plant cv. maçã under different sources of nutrients. A completely randomized design was employed, having a 2 x 4 factorial [2 densities of native FMA spores (D1 - 3,500 spores kg-1 soil and D2 - 7000 spores kg-1 soil) and four different concentrations of nutrient sources - three of a nutrient solution (SN 40%, SN 70% and SN 100%) and a 100% solution of bio-fertiliser (B4)], with three replications. After planting, the seedlings were inoculated with Fusarium oxysporum f.sp. cubense, and later the shoot dry matter, leaf phosphorus content, mycorrhizal colonization, soil pH and disease severity index were evaluated. The different nutrient sources affected the shoot dry matter, the phosphorus content, the mycorrhizal colonization and the disease severity index, but did not affect the pH of the soil-solution. The bio-fertiliser did not meet the nutritional demands of the plants, which remained underdeveloped, however it promoted intense mycorrhizal colonization and lower manifestations of fusarium. The latter increased under mineral fertilization.