Growth and Flowering of Greenhouse-grown Tomato Transplants in Response to Uniconazole

Uniconazole is approved for use as a chemical option on tomato (Solanum lycopersicum) for height control, but research is limited. In this study, 12 tomato cultivars were chosen with three cultivars each of indeterminate, determinate, heirloom, and container types. Plants were sprayed with a one-time application of 0, 2.5, 5, 7.5, or 10 mg center dot L-1 of uniconazole during the two-to four-leaf stage to evaluate height control. Results indicated no significant difference between concentrations for plant height, stem caliper, and plant dry weight. The greatest soil plant analysis development (SPAD) values were observed with the 10-mg center dot L-1 treatment. Flower response in 'Brandywine' to a single application of 0, 2.5, or 5 mg center dot L-1 of uniconazole demonstrated a greater number of flowers per plant at 5 mg center dot L-1, whereas no significant difference was shown for the number of flower clusters or the number of flowers per cluster other treatment levels. Using 2.5 mg center dot L-1 uniconazole was effective for reducing plant height across all cultivars of greenhouse-grown tomato seedlings compared with the control, whereas addition of 5 mg center dot L-1 was shown to increase the number of flowers in the heirloom cultivar Brandywine.