EFFECT OF NITROGEN AND NAPTHELIC ACETIC ACID ON GROWTH, YIELD AND NUTRIENT CONTENT OF STEVIA (Stevia rebaudiana Bertoni)

Abstract

The experiment was conducted to study the effect of nitrogen and napthelic acetic acid on growth, yeild and nutrient content of stevia. The trail was laid out in Randomized Complete Block Design (RCBD) with three replications. The treatments (nirogen) used were N 1 : control, N 2 : 105 kg ha -1 , N 3 : 140 kg ha -1 , N 4 : 175 kg ha -1 , N 5 : 210 kg ha -1 . The applied napthelic acitic acids (NAA) were H 1 : control, H 2 : 50 ppm, H 3 : 100 ppm and H 4 : 150 ppm. Data were collected on plant height (cm), number of branch plant -1 , number of leaves plant -1 , leaf area plant ), fresh weight plant (g), fresh leaf yield ha -1 (g), dry weight plant -1 -1 (kg), dry leaf yield ha (g), fresh leaf yield plant -1 -1 -1 (cm (g), dry leaf yield plant (kg), N(%), P (%), K (%), S (%), Ca (%), Mg (%), and Zn (µg g -1 ) of stevia leaf along with initial and post harvest soil analysis. Significant variations were observed in plant height, number of leaves plant -1 , leaf area plant ) number of primary and secondary branch plant -1 in different level of nitrogen application. Significant the highest plant height, number of leaves plant -1 , leaf area plant -1 (cm 2 ) number of primary and secondary branch plant -1 was observed in N 3 -1 (cm 2 treatmnet and the lowest was observed in N 1

(control) treatment at 21 DAT to 147 DAT, respectively. Applying 100 ppm NAA was the significant effect in increasing height in H 3 (100 ppm NAA) at 21 DAT to 147 DAT, respectively and the lowest plant height, number of leaves plant -1 , leaf area plant ) number of primary and secondary branch plant -1 was observed in control (NAA) treatment. The highest plant height, number of leaves plant -1 , leaf area plant -1 (cm 2 ) number of primary and secondary branch plant -1 heights was found in N 3 H 3 treatment and the lowest was found in N 1 (with no nitrogen application × with no NAA application) at all growth stages. The N, K, Mg, and Zn content of stevia leaf was significantly affected by different levels of nitrogen and NAA. The highest N, K, Mg, and Zn content was observed when the plot was treated with nitrogen140 kg ha -1 × 100 ppm NAA (N 3 H 3 ) and the lowest N, K, Mg and Zn content was recorded in the control treatment. Significantly highest fresh weight plant -1 , fresh weight ha -1 -1 (cm 2 H 1 , dry weight plant , dry weight ha -1 was observed in N 3 treatment and lowest was observed in N 1 treatment in stevia plant. The intraction effect of nitrogen and NAA in most of the combination should significantly the highest fresh weight plant -1 , fresh weight ha -1 , dry weight plant -1 , dry weight ha , fresh leaf yield ha -1 and dry leaf yield ha -1 was observed in N 3 H 3 -1 treatment and lowest was observed in N 1

treatment. The intraction effect of nitrogen and NAA in most of the combination should significantly the highest fresh weight plant -1 , fresh weight ha -1 1 , fresh leaf yield ha -1 and dry leaf yield ha -1 was observed in N 3 , dry weight plant H 3 and lowest was observed in N 1 H 1 treatment. Thus, the application of nitrogen and napthelic acitic acid had positive impact on leaf production resulted in higher yield economic stevia. From the result it can be recommended that nitrogen 140 kg ha -1 and NAA 100 ppm is might be suitable for commercial field cultivation of stevia production in Bangladesh.