ABSTRAK. Cemaran getah kuning merupakan masalah utama yang menyebabkan rendahnya mutu buah manggis. Keseimbangan ketersediaan hara kalsium (Ca) dan boron (B) dalam tanah diduga berperan penting dalam pengendalian cemaran getah kuning pada buah manggis. Tujuan penelitian ini untuk mendapatkan kombinasi dosis kalsium dan boron yang tepat untuk mencegah cemaran getah kuning pada buah manggis. Penelitian dilaksanakan di Purwakarta, Jawa Barat dari Bulan Nopember 2012 sampai Juni 2013. Rancangan percobaan yang digunakan ialah acak kelompok faktorial dengan tiga ulangan. Perlakuan terdiri atas dua faktor yaitu dosis Ca (0,0; 2,5; 5,0; dan 7,5 kg/pohon) dan dosis B (0,00; 0,77; 1,55; dan 2,32 g/pohon). Hasil penelitian menunjukkan bahwa pemberian Ca dan B dapat menurunkan persentase dan skor cemaran getah kuning pada aril dan kulit buah. Terjadi interaksi pemberian Ca dan B terhadap skor dan persentase cemaran getah kuning pada aril. Persentase cemaran getah kuning pada aril terendah (2,67%) diperoleh pada kombinasi dosis 5,0 kg Ca/pohon+1,55g B/pohon. Hasil penelitian ini dapat dijadikan pedoman kombinasi dosis Ca dan B untuk menanggulangi cemaran getah kuning pada buah manggis.Katakunci: Garcinia mangostana; Kalsium; Boron; Cemaran getah kuning ABSTRACT. Yellow latex contamination on mangosteen fruits is a major problem that causes poor quality of the fruits. Nutrient balance of calcium (Ca) and boron (B) in the soil is suspected to play an important role in the control of yellow latex contamination mangosteen fruits. The objective of this research was to obtain the best combination of calcium and boron dose appropriate to prevent contamination in the yellow latex mangosteen fruit. The research was councted at Purwakarta , West Java, from November 2012 to June 2013. The research arranged in factorial randomized block design with three replications. Treatment consisted of two factors of: Ca with dose 0.0; 2.5; 5.0; and 7.5 kg/tree, and B with dose 0.00; 0.77, 1:55; and 2:32 g/tree. The results showed that fertilizer of Ca and B can lower the percentage and score the yellow latex of the impurities on the aryl and the skin of mangosteen fruits. The interaction fertilizer doses of Ca and B to score and the percentage of contamination in yellow latex of aryl. Percentage the yellow latex of the impurities on the aryl (2.67%) lowest available doses of the combination of calcium and boron fertilizer 5.0 kg Ca/tree + 1.55 g B/tree. This results can be used as guide combination dose Ca and B for the control of yellow latex contamination on the mangosteen fruits.

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Yellow sap contamination (YSC) is one of the mangosteen quality constrain in Indonesia. Calcium is the prominent nutrient that influence the incidence of yellow sap contamination. A research with objective to observe the relationship between incidence YSC and Ca availability in soil as well as plant tissue was done in ten locations in West Sumatra, Lampung and West Java provinces. Purposive random sampling method was used to determine the site locations. The plant and soil samples were collected from 10 sites and ten tree per sites. Correlation analysis was used to measure the relationship between incidence YSC and Ca content in fruit endocarp, mesocarp, peel, soil and leaf. The result showed that there was a variation of incidence YSC in site location with range of 8.7%−54.04%; 4.0−51.6%; and 17.7−78.6% for percentage of YSC in fruit flesh, segmentation and peel, respectively. Ca content in soil, endocarp, mesocarp and leaf were given significantly negative correlation toward incidence YSC in fruit flesh and segmentation. Ca content in leaf part correlates significantly to Ca availability in soil, endocarp and mesocarp. Ca content in leaf in the range of 1.40- 1.70% indicates YSC less than 10%.

Manganese (Mn) is one of the essential micronutrients that plays a crucial role in plants' growth and development and is also considered a limiting factor for crop production. This study aimed to determine the critical level of Mn in soil and leaves for improving the quality of mangosteen fruit. The research was conducted in 2015 in several mangosteen production centers, including West Sumatra (Simalanggang and Banja Laweh), West Java (Karacak and Barengkok), Bali (Belimbing and Selamadeg). A well-maintained of fifteen to twenty years old mangosteen plants were used with uniform soil fertility. Purposive random sampling is conducted in each location to select ten plants from each site. Soil samples are taken from under the plant canopy around 0-30 cm in depth at the four cardinal directions. The terminal leaves that collected from the middle part of the plant canopy are used as the leaf samples. Physiological ripe fruits are taken after ripening with index 3-4. The parameters observed consist of (1) soil pH of H2O, Ca, Mg, Mn-available, (2) levels of Mn, Ca, Mg, and K in the leaves, (3) fruit quality (fruit weight, fruit diameter, fruit skin thickness, aryl weight, seed weight). The results showed the Mn content in the soil ranged from 18.89 to 33.63 ppm. Available Mn is negatively affected by pH, Ca, and Mg exchangeability. Soil Mn is linearly related to leaf Mn with R2 0.76. The critical values of Mn in leaf and soil for mangosteen plants in Indonesia were 425 ppm and 22 to 24 ppm, respectively.

Yellow latex is commonly called gamboge and is a latex produced in all parts of the mangosteen. Yellow sap becomes a problem when it gets out of the ruptured channel, and contaminates the aryl and pericarp. Ruptured channel of yellow latex is presumably because the walls of the epithelial cells of the yellow latex channels is Calcium deficiency. In addition, Boron has also the same function in maintaining the integrity of the cell wall. This research was aimed to know the roles of calcium and boron in controlling contamination yellow latex on the mangosteen fruit, and to obtain the best combination between calcium and boron in preventing the yellow latex contamination on mangosteen. The study was conducted in Purwakarta, West Java from November 2012 to June 2013. The study was arranged a randomized factorial with three replications. The treatment consists of two factors: dosages of Ca (0.0; 2.5; 5.0 and 7.5 kg / tree) and of B (0.00; 0.77; 1.55 and 2.32 g /tree). There was no interaction effect observed between calcium and boron fertilizer on fruit physical and chemical variables but there were significant interactions in quadratic levels of yellow latex contaminant in the mangosteen fruit. The percentage of fruit with minimum aryl contamination was 1.05 % at the optimum combination dose of 5.0 kg Ca/tree and 1.55 g B2O3/tree.