Journal of Crop Production and Processing

Enhancing the quality of transplant to reduce production costs is an important in tomato production. For this reason, the effects of growth retardants and the planting date on the tomato plant (Cheff) were investigated in this study. The first experiment involved five treatments (Paclobutrazol 0, 250 and 500 mg/L and Cycocel 0, 500 and 1000 mg/L), based on a complete randomized design in Laboratory. The second experiment was conducted as a factorial complete randomized design with two factors. These factors included seed soaking by growth retardants at 5 levels (Paclobutrazol 0, 250 and 500 mg/L and Cycocel 0, 500 and 1000 mg/L) and 3 levels of planting date (mid-December, January and February), with three replications. The results indicated that the effects of the growth Retardant on the diameter of transplant and the interaction of two treatments on the transplant length, the fresh weight and dry weight of shoots and roots, leaf area, chlorophyll content, plant height at the first flowering, the  number of flowers in the first cluster, and fruit quality were all significant.The thickest transplant (2.1 cm) was obtained by the application of paclobutrazol 500 and the lowest height of transplant (3.1 cm) was found in the combination of the first planting date with paclobutrazol in a 500 mg/L rate. The maximum yield of fruit (1.4 kg/plant) belonged to the first planting date. Overall, the findings indicated that to increase the quality of transplant, the 500 mg/L of paclobutrazol, and the first and second planting dates were more effective treatments.