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

Abstract

A field experiment was carried out under naturally ventilated greenhouse to assess the performance of tomato cv. Srijana as influenced by GA 3 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 (GA 3 ) (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 GA 3 , 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 GA 3 @ 50 ppm and it was 13.91%, 10.31% and 6.74% higher over GA 3 @ 0 ppm, GA 3 @ 25 ppm and GA 3 @ 75 ppm, respectively. Interactions between GA 3 and NAA levels were significant for all yield attributes. Regression analysis on the effect of GA 3 and NAA on the yield of tomato exhibited a polynomial regression equation, while the physical dose of GA 3 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 GA 3 @ 50 ppm and NAA @ 25 ppm under the controlled condition of Kaski, Nepal. • Average yield per hectare for tomato is very low in summer season particularly due to poor fruit set and flower drop. • GA3 and NAA can be used to address the problem of poor fruiting and flower drop. • Application of GA3 @50 ppm and NAA@25 ppm led to better fruit set and yield under protected condition. • This can boost the yield and encourage tomato growers to use PGR's at proper concentration under protected condition.