Synergistic effects of nitrogen and naphthalene acetic acid on growth, yield and nutritional content of Stevia (Stevia rebaudiana Bertoni)

Stevia farming in Bangladesh is increasingly significant due to limitations in cane sugar production and the rise in diabetic cases. This study examined how nitrogen and naphthalene acetic acid (NAA) affect Stevia development, production and nutritional content on the experimental farm of the regional station of the Bangladesh Sugarcrop Research Institute, Thakurgaon. Various nitrogen treatments (N1: untreated, N2: 105 kg ha-1, N3: 140 kg ha-1, N4: 175 kg ha-1, N5: 210 kg ha-1) and NAA applications (H1: untreated, H2: 50 mg/L, H3: 100 mg/L, H4: 150 mg/L) were administered employing a randomized complete block design (RCBD). Results showed that N3 and H3 treatments produced the highest yield, averaging 10.06 % more than other doses. Stevia leaf nutrients like nitrogen (3.47 %), potassium (0.19 %) and magnesium (0.15 %) were also influenced by N3H3 treatment. The study suggests that for Stevia cultivation in northern Bangladesh, an optimal nitrogen application rate of 140 kg ha-1 and an NAA concentration of 100 mg/L are recommended.