The length of the style plays an important role in the fruitset of the eggplant. The presence of indigenous phenomena in eggplant flowers reduces the production of this vegetable. Regarding the role of polyamines in a large number of physiological processes within plants, this study was conducted to investigate the flowering reaction of eggplant to the various concentrations of polyamines of spermidine. The experiment was carried as factorial arrangement of 2 × 4 in a randomized complete block design with two factors of race (TN74-116 (1) and TN74-237 (2)) application of spermidine in three replications and each replication including three plants in plastic tunnels of the Faculty of Agriculture, Isfahan University of Technology. The results showed that the spermidine growth regulator had no significant effect on vegetative characteristics (crown diameter, main stem height, total chlorophyll, a and b), as well as plant breeding characteristics including length, diameter and fruit weight. The number of fruits was also not affected by hormonal treatments, which It may be due to the loss of flowers due to the application of various toxins and the Late flowering in race 2. In general, race 2 was superior to the races of 1-4 inflorescence nodules due to the formation of the highest number of medium-styled flowers (effective in the formation of fruits) at concentrations of 0.5 and 1.0 mM spermidine. In race 2, increasing of spermidine concentration reduced the number of seeds compared to control treatment, but in the race 1 different concentrations of spermidine did not have a significant effect on seed number. Key words : Heterostylous, Spermidine, Long, medium and short-styled flowers, Eggplant