Avalia??o da incidência de antracnose, do desempenho e estado nutricional de variedades de mangueira, para cultivo organico, na regi?o centro-norte do Estado de S?o Paulo

摘要

The consumer's profile change, allied to the risk of toxic substances contamination, is inducing the search for ecological alternatives of fruits production. The objectives of this work were to evaluate the anthracnose incidence, the development and nutritional status of mango varieties organically cultivated in Pindorama, SP. Seventeen mango varieties were used. The experiment was designed in completely randomized blocks, with 17 treatments (varieties) and six replications. The anthracnose severity in leaves was evaluated by a diagrammatic scale, with grades attributed to the symptoms. The growth and development (plant height, stem and crown perimeter) and the nutritional state indicated by leaf analysis were used for evaluation of the varietal behavior. The varieties Bourbon, Rocha and Rosa could be considered very susceptible to anthracnose and IAC 111, Alfa, Beta and Parvin were resistant; the mango varieties presented the same growth pattern; the largest plant heights corresponded to the largest diameters of the stem and crown; the Parvin variety presented the best performance among the varieties in relation to the anthracnose resistance, height and diameter of the stem and crown, and could be recommended for organic cultivation. The Omega and Alfa varieties also presented good development and could be indicated for that cultivation, at least in that initial phase; Surpresa and Rosa varieties did not present good field development in relation to the others, and should not be recommended for the organic cultivation, mainly the variety Rosa, which is quite susceptible to anthracnose. The concentrations of N, P and K were higher in the vegetative phase of the plants, when compared to the low concentration of Ca; there was lack of Boron in all the studied varieties; Rosa variety probably suffered toxicity to the excess of manganese, causing decrease in its development.