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Musyarofah N, Susanto S, Aziz SA, Suketi K, Dadang. 2020. The diversity of ‘kristal’ guava (Psidium guajava) fruit quality in response to different altitudes and cultural practices. Biodiversitas 21: 3310-3316. The current study aimed to compare the quality of ‘kristal’ guava fruit harvested from different altitudes under different cultural practices. The study was conducted from January to March 2019. Four treatments were examined, i.e., fruit from low altitude-intensive cultural (LI), low altitude-less intensive cultural (LI), middle altitude-intensive cultural (MI), and middle altitude-less intensive cultural (ML). All treatments were arranged in a completed randomized design and each treatment had five trees as replicates The findings of the study showed that there was a variation of fruit quality in response to different altitudes and cultural practices. The fruits harvested from low altitudes were significantly bigger and heavier than the fruits harvested from middle altitude, irrespective of cultural practices. With regard to fruit softness, the fruits from middle altitudes were crispier than fruits from the low altitude. The chemical qualities of the fruits, indicated by TSS/TA ratio and vitamin C, were better in guava orchard under intensive cultural practice than less intensive cultural practice. The intensive cultural practice also improved the guava fruit size as compared to the less intensive cultural practice. This finding may be attributed to pruning which is performed in intensive cultural practice. More beneficial metabolites for human health such as vitamin E and caryophyllene were found in fruit from low altitude. MUSYAROFAH et al. – The diversity of ‘kristal’ guava fruit quality 3311 2019) and strangulation approach (Widyastuti 2019). However, there are no studies in regard to the quality aspect of the fruits. Fruit quality is one of the key factors that influence consumer preference. Generally, Indonesians value the outward fruit appearance, i.e., fresh-look and spot-free, and the size, i.e., preferably bigger fruits to smaller ones. To produce high-quality fruits, monitoring of the production process has to begin from the field. In that context, the key factors that affect fruit quality include; cultural practice and the environmental condition. One of environmental elements that could affect fruit growth is land altitude. Land altitude influences plant microclimate such as temperature and relative humidity. Previous studies reported the difference of fruit quality as the effect of land altitude in figs (Trad et al. 2013), pineapple guava (ParraCoronado et al. 2018) and Columbian guava (Solarte et al. 2014). Therefore, this study aimed to evaluate the ‘kristal' guava fruit quality in response to the different altitudes of growing location and cultural practice. MATERIALS AND METHODS Study site This research was conducted in January-March 2019 in Bogor, West Java, Indonesia. A total of four treatments were used; i.e., fruits that originated from low altitude with an intensive cultural practice (LI), low altitude with less intensive cultural practice (LL), middle altitude with intensive cultural practice (MI), and middle altitude with less intensive cultural practice (ML). The detailed variance of cultural practices is shown in Table 1. Procedures The fruits that originated from low altitudes were harvested from a local farmer’s orchard in Cikarawang village, Darmaga subdistrict (Bogor, Indonesia) with an altitude of about 200 m above sea level (asl). The fruits that originated from middle altitude were harvested from a local farmer’s orchard in Sukajadi village, Tamansari subdistrict with an altitude for about 550 m asl. Fruits were collected from 5-years-old ‘kristal' guava trees that exposed by treatment as showed in Table 1. All the treatments were arranged in a completed randomized design and each treatment had five trees as replicates. Each tree had five fruits observed as experimental units. Sampling was done by using the random method. Sampling in form of fruit picking was done during the same day in all locations. Observed variables were the external and internal quality of the fruit. The variables of external fruit quality were fruit weight, diameter and fruit softness, whilst, the variables of internal fruit quality were total dissolved solids (TSS), titratable acid (TA), the ratio of TSS/TA and vitamin C. The test of the aforementioned variables were conducted at the Postharvest Laboratory, Faculty of Agriculture, IPB University. To measure fruit softness (mm per 50g per second), a penetrometer was used in three spots for every fruit, i.e., upper part, middle part, and lower part of the fruit. Total soluble solids (TSS) were measured by dropping juice of blended fruit on a lens of a hand refractometer (Brix). Titratable acid (TA) was measured by using NaOH titration method. Distilled water was added to a sample of 10 mL of guava juice to reach the final volume of 100 mL. A portion of 10 mL of the solution was transferred to a new tube and three drops of phenolphthalein were added to the sample before titration. The sample was titrated with 0.1 N NaOH until the solution color turned to pink. The vitamin C content was measured by iodine 0.01 N titration method. This method was the modification of the previous report (Suntornsuk et al. 2002). Approximately, 25 g of fruit was blended into a juice and 10 mL of the filtered juice was mixed with distilled water to reach the final volume of 100 mL. 10 mL of fruit filtrate was transferred into 100 mL Erlenmeyer, and then it was combined with 2 mL of the starch indicator. The solution was titrated with 0.01 N iodine until the color turned to dark blue. The metabolites were profiled by using GCMS method (Agilent 7890 GC, 5975 mass selective detector). The sample for GCMS analysis was prepared in the form of methanol fruit extract of all fruit parts. The GCMS instrument produced a profile of metabolites that detected on the fruit extract. Data analysis All data, except the GCMS data, were pooled and analyzed using analysis of variance (F test). Any significant differences between treatments were further tested by Duncan Multiple Range Test at α 5% (Mattjik and Sumertajaya 2013). For the GCMS results, data were processed by using R stat with a metabolomic package to form heatmap cluster gram. Table 1. Description of ‘kristal’ guava cultural practices in different altitude