ABSTRACT 

A field experiment was conducted at the Horticulture Farm, Bangladesh Agricultural University, Mymensingh to study the combined effect of different levels of GA3 and NAA on growth and yield of tomato. The experiment consisted of ten (10) treatments viz.T0 = G0N0 (control), T1= GA3 @ 40 ppm + NAA @ 5 ppm, T2= GA3 @ 50 ppm + NAA @ 5 ppm, T3= GA3 @ 60 ppm + NAA @ 5 ppm, T4= GA3 @ 40 ppm + NAA @ 10 ppm, T5= GA3 @ 50 ppm + NAA @ 10 ppm, T6= GA3 @ 60 ppm + NAA @ 10 ppm, T7 = GA3 @ 40 ppm + NAA @ 15ppm, T8= GA3 @ 50 ppm + NAA @ 15 ppm, T9= GA3 @ 60 ppm + NAA @ 15 ppm. Experiment laid out in the randomized complete block design (RCBD) with three replications. The results of the experiment revealed that the extent of plant establishment percentage, plant growth, day to first flowering, number of clusters plant-1, number of flowers cluster-1 , number of flower plant-1, number of fruits plant-1, fruit weight plot-1, fruit weight ha-1 were significantly influenced by different concentrations of GA3 and NAA. Combined effect of GA3 and NAA produced the maximum plant succession percentage (100), plant height (71.33 cm), number of leaves plant-1(36.89) and plant diameter at 67 DAT from the treatment G2N2 that means at treatment T5. Maximum no. of clusters plant-1 (15.11), no. of flowers cluster-1 (6.11), number of flower plant-1 (46.22), number of fruits plant-1(13.44), individual fruit weight (85.70 g), fruit weight plant-1(1.13kg), yield plot-1(13.14 kg) and yield ha-1 (36.50 tha-1) obtained the treatment T5.

Key words: Tomato, GA3, NAA and growth.

Introduction

Tomato ( Lycopersicon esculentum Mill.), belonging to the family Solanaceae is originated in tropical America (Salunkhe et al., 1987) most likely in the region of Andes Mountain in Peru and Boloivia (McCollum, 1992). It is one of the most highly praised vegetables consumed widely and a major source of vitamins and minerals (Bose and Som, 1990). The low yield of tomato in Bangladesh, however, is still prevailing, where plant growth regulators (PGR’s) might be used as a useful alternative to increase crop production. The most widely available plant growth regulator is GA3 or gibberellic acid, which induces stem and internode elongation, seed germination, enzyme production during germination and fruit setting and growth. Naphthalene Acetic acid has an important effect on the fruit retention of several vegetables as well as horticultural crops and thus increasing the yield sustainability. Application of plant growth regulator for improving the yield and quality of many vegetable crops has been emphasized by several workers (Meena, 2008). However, the improvement in the yield and quality of the crops mainly depends on the concentration of plant growth regulator and time of application. Under the circumstances, the present piece of research was undertaken in view of the following objectives to study the combined effect GA3 and NAA on growth and yield of tomato and to increase the yield of tomato by using plant hormones and to find out the best combination of GA3 and NAA for obtaining the maximum yield.

Materials and Methods

The field experiment was conducted at the Horticultural Farm, Bangladesh Agricultural University, Mymensingh during the period from October, 2016 to February, 2017 to determine the effect of staking and stem pruning on the growth. The soil of the experimental plot was sandy loam in texture. It belongs to the