Establishment of specific DRIS standards for mango cultivars Tommy Atkins, Kent and Keitt compared to generic standards in the Sub-Middle São Francisco Valley

The Diagnosis and Recommendation Integrated System (DRIS) is a promising diagnostic method in the nutritional assessment of commercial crops. The aim of this work was to establish and compare specific DRIS nutritional standards for Tommy Atkins, Kent and Keitt mango tree, as well as for the group of cultivars in the sub-Middle São Francisco Valley, Brazil. The study was carried out in commercial orchards of Tommy Atkins, Kent and Keitt cultivars, in the Sub-Middle São Francisco Valley. To form the database, leaf samples were collected in the pre-flowering, where the nutritional contents were determined. DRIS norms were established and together with the data of productivity and nutritional contents of the subpopulations of high and low productivity were compared by the t test. The contents of S and micronutrients showed greater variability. The nutritional contents of the high-productivity subpopulation were less distorted. The nutrients P, K, Mg, S, Mn and Zn for Tommy, K for Kent, N for Keitt and P, K and S for the set of cultivars were higher in the high productivity subpopulation. The specific norms for each cultivar were more consistent and could serve as a reference for nutritional diagnostics of the mango tree in the region.