Growth and Yield of Stevia (Stevia rebaudiana Bertoni) as Influenced by Plant Density and Pinching

A field experiment was carried out to standardize spacing and pinching time to enhance the yield and quality of stevia (Stevia rebaudiana Bertoni) at the Department of Agronomy, College of Agriculture, Thrissur, Kerala, from September 2021 to May 2022. The design of the experiment was factorial RBD and replicated thrice. The experiment comprised three levels of spacing (15 cm × 10 cm, 20 cm × 10 cm, and 15 cm × 15 cm) and four pinching intervals (pinching at 20 days after planting (DAP), pinching at 30 DAP, pinching at flower bud initiation and no pinching) in all possible combinations. The plants grown with closer spacing (15 cm × 10 cm) were the tallest at all growth stages. The pinching of the apical bud caused a reduction in plant height and increased the number of branches. Pinched plants recorded higher fresh and dry leaf weights than plants left non-pinched. More leaves were registered under the wider (15 cm × 15 cm) spacing than narrower spacings. Pinching favored the formation of more lateral buds, producing a more significant number of branches and, finally, more leaves per plant. High-density planting of stevia yielded the highest aboveground fresh mass (10925 kg ha-1), whereas lower plant densities yielded the lowest aboveground fresh mass (7330 kg ha-1). The stevia planted at a spacing of 15 cm × 10 cm and pinched at flower bud initiation (11980 kg ha-1) produced higher herbage.