FEASIBILITY STUDY TO ALLEVIATE THE TRANSLUCENT FLESH AND GAMBOGE DISORDERS OF MANGOSTEEN (GARCINIA MANGOSTANA L.) BY SPRAYING WITH CALCIUM CHLORIDE

Translucent flesh disorder (TFD) and gamboge disorder (GD) in mangosteen are the main problems that limit export fruit quality. An imbalance or deficiency of calcium (Ca) in mangosteen trees may cause these fruit disorders. Two experimental sites were established at Nakhon Sri Thammarat, southern Thailand to investigate the effects of CaCl₂ sprayed on the incidence of TFD and GD in mangosteen fruits. The experiment was designed as factorial design with 2 main factors: 1) fruit positions (outer and inner canopy) and 2) concentrations of Ca sprayed (wt/vol) (control (no spray), 5 and 10% CaCl₂). Six treatments with 3 replicates were arranged in a completely randomized design under field conditions. The mangosteen fruits were sprayed at 6, 7 and 8 weeks after bloom. Leaves were sampled at bloom and at harvest, while fruits were sampled at harvest. Calcium concentrations of the leaf, peel and flesh of all treatments were analyzed. Results indicated that applications of CaCl₂ could increase Ca concentrations in peel and flesh of mangosteen fruits. Spraying with 10% CaCl₂ could increase the percentages of normal fruits in both outer and inner canopy positions, whereas the percentages of defected fruits with TFD and GD decreased.