The Effect of Rainfall on Yellow Crude on Mangosis Fruit (Garciniamangostana L.)

Abstract

The research was carried out through case studies at six locations of mangosteen production centers in West Sumatra during the 2018 harvest season. The results showed that mangosteen fruit damage by yellow sap was distinguished from yellow sap in exocarp and endocarp with varying percentages between research locations. There was no correlation between yellow sap in exocarp and endocarp (r=0.0656). Yellow sap in exocarp and endocarp correlate with rainy days. The intensity of rainfall during the fruit development period does not correlate with yellow latex in the endocarp but the fluctuation in rainfall is very influential. Yellow sap at the lowest endocarp (15%) was found at the location of Station-5 with the lowest rainy day (44 days) and low rainfall fluctuations (40-240 mm/month) and the highest (47%) at Station-3 (104 days rain and rainfall fluctuations 96-512 mm/month). The Station-4 area with lower rainy days (80 days) but has high rainfall fluctuations (73-954 mm/month) also shows yellow latex at a higher endocarp (35%) compared to other locations. Yellow gum at the lowest exocarp (32%) found in Station-2 (63 rainy days, 00 m asl) and highest (69%) in Station-6 (94 rainy days, 490 m asl). Effect of rainy days and altitude on the sap yellow on the skin of the fruit can be explained through its relationship with environmental conditions needed for the proliferation of insects that cause yellow sap on the mangosteen rind.