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⋅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⋅L–1 treatment. Flower response in ‘Brandywine’ to a single application of 0, 2.5, or 5 mg⋅L–1 of uniconazole demonstrated a greater number of flowers per plant at 5 mg⋅L–1, whereas no significant difference was shown for the number of flower clusters or the number of flowers per cluster at other treatment levels. Using 2.5 mg⋅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⋅L–1 was shown to increase the number of flowers in the heirloom cultivar Brandywine.

[1]  J. Wünsche,et al.  Air-based Mechanical Stimulation Controls Plant Height of Ornamental Plants and Vegetable Crops under Greenhouse Conditions , 2021, HortTechnology.

[2]  D. Leskovar,et al.  Growth suppression by exogenous abscisic acid and uniconazole for prolonged marketability of bell pepper transplants in commercial conditions , 2015 .

[3]  J. Bethke,et al.  Effect of Uniconazole on the Control of Plant Height and Fruit Yield of Potted Tomato, Pepper, and Eggplant , 2015 .

[4]  C. Vavrina.  An Introduction to the Production of Containerized Vegetable Transplants 1 , 2011 .

[5]  K. Harrison,et al.  Commercial tomato production handbook , 2010 .

[6]  R. C. Squire,et al.  Managing transplant size and advancing field maturity of fresh tomatoes and peppers , 2007 .

[7]  C. Wood,et al.  TOMATO LEAF CHLOROPHYLL METER READINGS AS AFFECTED BY VARIETY, NITROGEN FORM, AND NIGHTTIME NUTRIENT SOLUTION STRENGTH , 2002 .

[8]  W. Rademacher.  GROWTH RETARDANTS: Effects on Gibberellin Biosynthesis and Other Metabolic Pathways. , 2000, Annual review of plant physiology and plant molecular biology.

[9]  T. Nishizawa,et al.  Effects of Rooting Volume Restriction on the Growth and Carbohydrate Concentration in Tomato Plants , 1998 .

[10]  E. Curry,et al.  Chemical regulation of vegetative growth , 1991 .

[11]  Yin-Tung Wang,et al.  Uniconazole controls growth and yield of greenhouse tomato , 1990 .

[12]  Thomas M. Blessington,et al.  Growth of Four Tropical Foliage Species Treated with Paclobutrazol or Uniconazole , 1990 .

[13]  C. Marr,et al.  Holding Tomato Transplants in Plug Trays , 1990 .

[14]  L. Gregg.  Uniconazole Affects Vegetative Growth, Flowering, and Stem Anatomy of Hibiscus , 1989, Journal of the American Society for Horticultural Science.

[15]  D. A. Bailey,et al.  Whole-plant Response of Easter Lilies to Ancymidol and Uniconazole , 1989, Journal of the American Society for Horticultural Science.