Heat unit, phenology and fruit quality of Salak (Salacca zalacca var. amboinensis) cv. Gulapasir on different elevation in Tabanan regency-Bali

摘要

Each cultivar of zalacca could adapt to elevation, which has close relationship with the plant tolerance to temperature. However, heat unit of zalacca cv. Gulapasir, which are required to reach definite phase if they are grown in Tabanan areas have not known yet. The main objective of the research was to study heat unit, phenology and fruit quality of zalacca cv. Gulapasir planted on different elevation in Tabanan-Bali. The research was designed using Randomized Completely Design (RCD), with one factor as dependent variable along with ten replications. The independent variable was the site altitude of three locations that includes Saribuana village (460 m asl), Pajahan village (570 m asl), and Batungsel village (700 m asl). The phenologic determination of zalacca is based on the heat unit, which is counted using equation [(T.max + T.min)/2]-T.base, in which T.max and T.min is daily mean maximum and minimum temperatures, respectively, and T.base is the basic temperature. The parameters measured were the emergence of midrib and spatha, the numbers of fruits per bunch, fruit weight, the harvest time, the thickness of the mesocarpium, total soluble solids (TSS), and total acid levels. Data was analyzed by analysis of variance, if the test of variance showed significant difference then it would be followed by LSD test in level 5%. Result of the research showed that different heat unit causes diverse phenology of the zalacca's components, which include the growth of midrib, the emergence of spatha, and the harvest time. Ripe-consumed zalacca was planted in Saribuana(460 m asl) in 7.4 days earlier than zalacca planted in Batungsel, which was 4.2 days earlier than others that were planted in Pajahan. The zalacca cv. Gulapasir were planted at Pajahan (570 m asl) shows the higher quality of fruit such as thickness of the mesocarpium, edible portion, TSS/total acidity ratio, and numbers of fruit then the others two elevation.