Control of fruit cracking in Clementino mandarin plants

One of the widest spread physical defects limiting citrus production is the cracking of the skin and splitting of detached fruits. The objective of this work was to evaluate different doses of calcium nitrate and calcium and magnesium carbonate to control the splitting fruits, the production, nutrition and quality 'Clementine' mandarin fruits. The following treatments was to evaluate: T1: control, T2: 225 g Ca [(N[O.sub.3]).sub.2], T3: 450 g Ca [(N[O.sub.3]).sub.2], T4: 720 g Ca [(N[O.sub.3]).sub.2] and T5: 720 g of CaMg [(C[O.sub.3]).sub.2] plan[t.sup.-1].They was applied in March (50 %) and September (50 %), spring budding period, during three consecutive seasons. Complete randomized blocks, design with four replicates were done. All seasons, in March, foliar samples were, for each treatment taken, for determining concentrations of nitrogen, phosphorus, potassium, calcium and magnesium. During February and March, detached fruit under the crown of each plant was between February and March recorded. At harvest time, 30 fruits were in the experimental plot sampled and equatorial diameter, bark thickness, percentage of juice, acidity, content of total soluble solids and maturity index were measured. The contribution of calcium had a positive effect on the production, significantly increasing the number of fruits per plant and the fewer number of fruits that fell due to cracking of the bark. T3 and T4 with calcium in the form of calcium nitrate and T5 with calcium and magnesium in the form of dolomite presented higher contents of leaf calcium with respect to T1, which only received NPK and Mg contribution through fertilization with 15- 6-15-6. Key words: quality, Citrus, nutrition, production