Effect of GA3 and NAA on tomato production under protected cultivation in Kaski, Nepal

A field experiment was carried out under naturally ventilated greenhouse to assess the performance of tomato cv. Srijana as influenced by GA3 and NAA during the summer season of 2018–2019 at Kham Ghale Krishi farm, Pokhara, Kaski, Nepal. The treatments comprised of four levels of Gibberellic Acid (GA3) (i.e., 0 ppm, 25 ppm, 50 ppm and 75 ppm) combined with four different levels of Naphthalene Acetic Acid (NAA) (i.e., 0 ppm, 25 ppm, 50 ppm and 75 ppm). Treatments were replicated thrice in the two factorial RCBD. The results revealed that the fruit yield was significantly influenced by the levels of GA3, NAA and their interactions. Among four levels of NAA, the highest yield (109.91metric ton ha-1) of tomato was recorded with NAA @ 25 ppm which was 10.37%, 17.47% and 24.78% higher over NAA @ 0 ppm, NAA @ 50 ppm and NAA @ 75 ppm, respectively. Similarly, a significantly higher yield (103.46metric ton ha-1) of tomato was attained with GA3 @ 50 ppm and it was 13.91%, 10.31% and 6.74% higher over GA3 @ 0 ppm, GA3 @ 25 ppm and GA3 @ 75 ppm, respectively. Interactions between GA3 and NAA levels were significant for all yield attributes. Regression analysis on the effect of GA3 and NAA on the yield of tomato exhibited a polynomial regression equation, while the physical dose of GA3 and NAA was observed to be 52.65 ppm and 20.29 ppm, respectively. It could be suggested that the production of tomato could be improved by the combined application of GA3 @ 50 ppm and NAA @ 25 ppm under the controlled condition of Kaski, Nepal.