Crop productivity, steviol glycoside yield, nutrient concentration and uptake of Stevia rebaudiana Bert. under Mediterranean field conditions.

Stevia rebaudiana Bertoni (Asteraceae Family), characterized by a high content of steviol glycosides (SG) in its leaves, represents an interesting source of non-sucrose and no-calorie sweeteners. Stevia, which is native to Paraguay, is a relatively new crop for the Mediterranean region, where it is grown as an annual or poly-annual crop. In order to assess the crop’s environmental requirements, productive performance and nutrient uptakes, a two-year field experiment was carried out in north-eastern Italy, where the species had never previously been cultivated. The aim was to evaluate the effects of important pre-harvest factors, such as cultivation site, harvest time and their reciprocal interaction, on productivity, leaf SG yield and nutrient requirements. Results showed that the timing of the harvest and the pedo-climatic conditions of the cultivation sites had a significant effect on the main biometric traits, total and leaf dry yield, SG production, macronutrient concentration and uptake.