Sinergism among auxins, gibberellins and cytokinins in tomato cv. Micro-Tom

The aim of this study was to evaluate the effect of isolated and combined applications of gibberellic acid (gibberellin), indolbutyric acid (auxin) and kinetin (cytokinin) on vegetative and reproductive development of tomato test plants (Solanum lycopersicum cv. Micro-Tom), to better elucidate the interactions among these hormonal classes. The following treatments were accomplished through foliar application: GA(3) (5 mg L-1); IBA (5 mg L-1); KIN (9 mg L-1); GA(3) + IBA (5 mg L-1 + 5 mg L-1); GA(3) + KIN (5 mg L-1 + 9 mg L-1); IBA + KIN (5 mg L-1 + 9 mg L-1); GA(3) + IBA + KIN (5 mg L-1 + 5 mg L-1 + 9 mg L-1) and Stimulate (R) (100 mL L-1). Plants from the control were sprayed with water. Stimulate (R), is a commercial liquid formulation containing KIN (90 mg L-1), GA(3) (50 mg L-1) and IBA (50 mg L-1). We analyzed the shoot dry matter (g), root dry matter (g); fruit fresh matter (g); fruit dry matter (g) and fruit size (cm). The experimental design was completely randomized with nine treatments and fifteen replications. The treatment means were compared by Tukey's test. Some combined applications of GA(3), IBA and KIN or Stimulate (R) promoted significant increases in the dry matter accumulation of roots and fresh and dry matter of fruit compared to the control. Besides the perspective to extend such results for commercial tomato production, the relevance of known hormonal interactions for the results obtained is discussed.