SEASONAL COMPARATIVE ANALYSIS OF GROWTH PARAMETERS AND STEVIOSIDE CONTENT OF STEVIA REBAUDIANA VAR. MORITA II

The genus Stevia is known for its natural sweetening property because of the presence of different entkaurene glycosides. Among these compounds stevioside is the highest and mainly responsible for the sweetening property. The most important characteristics of stevioside is its non-calorific nature, due to which it is highly preferable for using in food and medicines. The antimicrobial properties of stevioside also makes it a superior constituent of the medicines used for different skin diseases. Because of these special characteristics, cultivation and commercialization of Stevia have become widespread throughout the world. Many Indian states have already successfully cultivated this plant species in large scale. But, being a country having different regions with prominent seasonal variation, the yield of stevioside can be different throughout the year, which will affect the commercial value of the compound and hence can directly affect our farmers. This seasonal variation is also persistent in the northeast Indian state, Assam, which is highly affected by extensive rain in the monsoon. Therefore, an investigation was under taken to analyze the stevioside content in three different seasons: summer, rainy and winter, taking Stevia rebaudiana var. MoritaII as the plant of study. The results showed a distinct variation in the stevioside concentration in different seasons. At the p=0.01 level, there was a significant positive association between the number of branches per plant and leaf fresh weight (r=0.87*), leaf dry weight (r=0.90**), stevioside concentration (r=0.90**) and stevioside percentage (r=0.88**). This study will be helpful to the farmers for selecting the suitable season for the cultivation of Stevia rebaudiana var. Morita II for an increased stevioside content.