Influence of growing conditions and date of planting on the yield and quality of stevia (Stevia rebaudiana Bertoni)

Abstract

A field study was carried out from May to November 2020, to assess the effect of growing conditions and planting date on herbage yield and quality of stevia (Stevia rebaudiana Bertoni) . The design of the experiment was split plot with two main plots (open and 50 per cent shade) and four sub plots (May 15 th , June 15 th , July 15 th , and August 15 th ). Higher plant height was observed under 50 per cent shaded conditions. Leaf weight, herbage yield, and steviol glycoside contents were higher under open growing conditions . The herbage yield was higher in the treatment combination of planting in May under open conditions (7800 kg ha -1 ) and was on par with the August planting (7212 kg ha -1 ) under open conditions. Lower herbage yield was recorded in June planting (3872 kg ha -1 ) under 50 per cent shade and was on par with the July planting (4077 kg ha -1 ) under 50 per cent shade . Under open conditions, the crop planted in May recorded the highest total steviol glycoside content (9.05 percent). A strong positive correlation was observed between growth parameters of stevia with maximum and minimum temperatures, whereas the correlation with rainfall was negative.