Application of calcium to decrease yellow sap contamination at different positions of Garcinia mangostana L.

Abstract

The present research aimed at studying the effects of Ca application,
through soil fertilization, on yellow sap contamination based on the position of the fruits on the canopy of the tree. The tree was divided into 6 sectors based on the differences in light exposure i.e. sector 1, 2, and 3 for shaded fruit positions and sector 4, 5, and 6 for well-exposed (to light) fruit positions. The present study used a Randomized Complete Block design (RCBD), consisting of 2 treatments i.e. 0 kg Ca/tree and 4.8 kg Ca/tree. The results revealed that Ca treatment lead to an increase in Ca-pectate content in pericarp. In addition, the exposed fruit position allegedly increase the absorption of Ca-pectate to the
fruit. Thus, it is important to both apply Ca on the soil and ensure that the fruit, in the canopy, gets enough light to decrease the occurrence of yellow sap contamination. The well-exposed position of the fruit, in the 4.8 kg Ca/tree treatment during anthesis, had increased the Ca-pectate content of the pericarp which, in turn, resulted in a decrease in yellow sap contamination in segment, aryl, and rind of the mangosteen fruit.