EFFECT OF EXCESS WATER ON THE INCIDENCE OF TRANSLUCENT FLESH DISORDER IN MANGOSTEEN (GARCINIA MANGOSTANA L.)

A problem limiting profitable mangosteen production in southern Thailand is the occurrence of translucent flesh disorder (TFD), caused by heavy-rainfall during pre-harvest. To investigate this impact, an experiment was conducted under field conditions. Four treatments were arranged as follows: 1. rewatering to field capacity by sprinkler system when soil water potential fell to -100 kPa (T1), 2. daily sprinkler irrigation (30 L hr^-1) for 10 hours (T2), 3. heavy rain simulation by daily sprinkling (60 L hr^-1) above and inside the tree canopy for 10 hours (T3), and 4. control, where the trees were exposed to naturally occurring rainfall conditions (T4). With 4 replicates in each treatment, 16 trees aged 13-years were used. Trees in T1, T2 and T3 were under a wooden structure that was roofed with transparent plastic sheeting. The treatments were started at 9 weeks after blooming. The results showed that the highest percentage of translucent flesh disorder fruits occurred in T3 (60.5%), and this result was significantly different from T2 (23.7%), T4 (7.0%) and T1 (0%), respectively. Under severe conditions of excess water in T3, fruit cracking was concurrently found in fruits with translucent flesh disorder. Although there was no translucent flesh disorder fruits in T1, 87.7% of the harvested fruits suffered from gamboge disorder (GD), which may have been due to sudden increase in soil moisture.