Case Studies of Decrease in Crop Stevia (Stevia rebaudiana Bertoni) at Tawangmangu Region, Karanganyar Regency

Abstract

Stevia rebaudiana Bertoni is a natural sweetener plant, including the family Asteraceae. Stevia plants are needed in many industries, food and herbal medicine. High demand for stevia can not be supplied from the local culture, but must be imported mainly from China. So far, stevia is cultivated in may areas Twangmangu, Karanganyar Regency. Since the last five years, production and quality stevia has decrease in the production of stevia plant in Tawangmangu region, Karanganyar regency. The research were conducted by observation study site and methods of cultivation, morfoanatomy, biomass and gulucoce content of stevia plants from Tawangmangu. The result showed that the location of stevia growing in Tawangmangu area lies at an altitude of 1200 - 1800 masl, andosol soil type, soil pH and soil moistureranged from 4.5 to 6 and 47% - 80% range, 22-31 C air temperature, and humidity 60 - 70%. Increase in temperature is thought to be the main causes for the production of stevia plants, this can be seen from the morphology of the relatively smaller than the size of leaves, roots and intrernodus. Breedling methods are less effective because of explants taken directly from the previous crop and only intended for fulfillment of production land. Stevia plant groeth are not optimum in the region with an irreglar drainage which causes an increase in the number of diseased plants more. Cultivation of stevia in polyculture with some other crops such as chili pepper, banana, cassava, maize, cashew, mustard, and other plants, causing microclimate that does not support optimal plant biomass is low while high water content, causing the decay of a high percentage (>30%).