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  Eur.J.Hortic.Sci. 80 (6) 280-287 | DOI: 10.17660/eJHS.2015/80.6.3
ISSN 1611-4426 print and 1611-4434 online | © ISHS 2015 | European Journal of Horticultural Science | Original article

Trinexapac-ethyl modifies plant architecture of ornamental pepper

S. Sever Mutlu and N. Kurtulan
Department of Landscape Architecture, Faculty of Agriculture, University of Akdeniz, Antalya, Turkey

Compact and well branched ornamental peppers are commercially preferred. Plant growth regulators (PGR) and pinching, removal of shoot apices, are used to create ornamentals with high aesthetic value. Trinexapac-ethyl (TE) is a foliarly absorbed plant growth regulator (PGR) and belongs to acylcyclohexadione chemical family that inhibits gibberellic acid biosynthesis. The objective of this study was to investigate possibility of using TE as a PGR in ornamental pepper (Capsicum annuum L.) production to suppress vertical growth and/or substitute for pinching to produce more compact and quality plants. The 0, 2, 4, 8, and 12 ppm TE was foliarly applied onto either pinched or non-pinched plants. Pinching and TE reduced the canopy height up to 25% and 38%, respectively. TE along with pinching reduced Height/Diameter (H/D) ratio from 2.3 down to 1.5, a more commercially desired compactness. TE increased the chlorophyll content and total fruit number. TE may substitute costly pinching treatment for growth control. The absence of phytotoxicity and improved production may justify recommendation of TE for commercial ornamental pepper production.

Keywords pinching, plant growth regulator, H/D ratio, Capsicum annuum, fruit number, gibberellin biosynthesis inhibitor

Significance of this study

What is already known on this subject?

  • Pinching and/or plant growth regulators (PGR) (i.e., paclobutrazol, daminozide) are used to improve compactness of ornamental plants. Pinching increases the production cost and use of paclobutrazol has been revoked in some EU member states and use of daminozide restricted. Trinexapac-ethyl (TE) is registered for height control of grasses. However, the efficacy of TE on growth of ornamental pepper is unknown.
What are the new findings?
  • TE and pinching reduced the canopy height and Height/Diameter (H/D) ratio. TE delayed the fruit set but increased the total fruit number and chlorophyll content without causing phytotoxicity.
What is the expected impact on horticulture?
  • TE may offer a safer PGR alternative in production of commercially acceptable compact plants and may substitute pinching treatment, providing an economic advantage. Results of this study on ornamental pepper and of previous report on chrysanthemum indicate that TE as PGR may find a larger use on other dicot ornamental species.

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  • Aloni, B., and Paskar, T. (1987). Antagonistic effects of paclobutrazol and gibberellic acid on growth and some biochemical characteristics of pepper (Capsicum annuum) transplants. Sci. Hortic. 33, 167–177.

  • Arzani, K., and Roosta, H.R. (2004). Effects of paclobutrazol on vegetative and reproductive growth and leaf mineral content of mature apricot (Prunus armeniaca L.) trees. J. Agric. Sci. Technol. 6, 43–55.

  • Ball, V. (1985). Ornamental pepper and Christmas cherry. In Ball red book, V. Ball, ed. (Reston, Va: Reston Publishing), pp. 601–603.

  • Bangreth, F. (1994). Response of cytokinin concentration in the xylem exudate of bean (Phaseolus vulgaris L.) plants to decapitation and auxin treatment and relationship to apical dominance. Planta 194, 439–442.

  • Basavaraj, S.H. (1984). Influence of pinching and growth retardants on growth and development of marigold cv. African giant. M.Sc. Thesis, University of Agricultural Sciences, Dharwad.

  • Basra, A.S. (2000). Plant growth regulators in agriculture and horticulture, their role and commercial uses. (Binghamton, NY: The Haworth Press).

  • Bird, R.E., and Conner, J.L. (1999). Container grown azalea response to sumagic sprays. In Proceedings of 44th SNA Research Conference, B.L. James, ed. (Atlanta, GA), pp. 274–276.

  • Bodson, M., and Thomas, E. (1993). The role of gibberellins in the control of inflorescence bud initiation of Rhododendron simsii. Acta Hortic. 378, 113–121.

  • Chen, J.G., Zhao, Y.H., Zhou, X., Mao, L.S., and Chen, X.X. (1997). Fluctuation in levels of endogenous hormones after decapitation and 6-benzyl amino purine treatment in Azalea and their relationship to apical dominance. Sci. Hortic. 71, 49–58.

  • Davis, T.D., Steffans, G.L., and Sankhla, N. (1988). Triazole plant growth regulators. Hortic. Rev. 10, 63–105.

  • Debra, R.B., and Lewis, A.J. (1986). Pre plant application of growth retardants to pinched and un pinched chrysanthemum cuttings. Sci. Hortic. 28, 159–164.

  • Dorajeerao, A.V.D., and Mokashi, A.N. (2012). Growth analysis as influenced by pinching time in garland chrysanthemum (Chrysanthemum coronarium L.). Global J. Biosci. Biotech. 1, 242–247.

  • EPA. (2015). Trinexapac-ethyl Interim Registration Review Decision Case 7228.!documentDetail;D=EPA-HQ-OPP-2008-0657-0027.

  • Ervin, E.H., and Koski, A.J. (2001). Kentucky bluegrass growth responses to trinexapac-ethyl, traffic, and nitrogen. Crop Sci. 41, 1871–1877.;

  • Fagerness, M.J., and Yelverton, F.H. (2000). Tissue production and quality of ‘Tifway’ bermudagrass as affected by seasonal application patterns of trinexapac-ethyl. Crop Sci. 40, 493–497.

  • Faiss, M., Zalubilova, J., Strnad, M., and Schmulling, T. (1997). Conditional transgenic expression of the ipt gene indicates a function for cytokinins in paracrine signaling in whole tobacco plants. Plant J. 12, 401–415.

  • Gardner, D.S., and Metzger, J.D. (2005). Use of Trinexapac-ethyl for growth regulation of Chrysanthemum (Dendranthema Χ grandiflora). HortScience 40, 670–674.

  • Grossi, J.A.S., DeMoraes, P.J., De Araujo Tinoca, S., Barbosa, J.G., Finger, F.L., and Cecon, P.R. (2005). Effects of paclobutrazol on growth and fruiting characteristics of ‘Pitanga’ ornamental pepper. Acta Hortic. 683, 333–336.

  • Grossman, K. (1991). Plant growth retardants: Their mode of action and benefit for Physiological research. In Progress in plant growth regulation, C.M. Karssen, L.C. van Loon, and D. Vreugdenhil, eds. (The Netherlands: Kluwer Academic), pp. 788–797.

  • Halmann, M. (1990). Synthetic plant growth regulators. Adv. Agron 43, 47–105.

  • Hammer, P.A. (1980). Other flowering pot plants. In Introduction to Floriculture, R.A. Larson, ed. (New York: Academic Press), pp. 442–445.

  • Heckman, N.L., Gaussoin, R.E., Horst, G.L., and Elowsky, C.G. (2005). Growth regulator effects on cellular characteristics of two turfgrass species. Int. Turfgrass Soc. Res. J. 10, 857–861.

  • Hisamatsu, T., Koshioka, M., Satoshi, S., and King, R.W. (1998). Effect of gibberellin and GA biosynthesis inhibitors on growth and flowering of stock [Matthiola incana (L.) R. Br.]. J. Jpn. Soc. Hortic. Sci. 67, 537–543.

  • Jhon, A.Q., and Paul, T.M. (1995). Influence of spacing and pinching treatments on growth and flower production in chrysanthemum (Chrysanthemum morifolium Ramat) cv. Flirt. Prog. Hortic. 27, 57−61.

  • Johnson, B.J. (1992). Response of Centipedegrass (Eremochloa ophiuroides) to plant-growth regulators. Weed Technol. 6, 113–118.

  • Janssen, B.J., Drummond, R.S., and Snowden, K.C. (2014). Regulation of axillary shoot development. Curr. Opin. Plant Biol. 17, 28–35.

  • Katz, E., Ziv, O., Venkatachalam, R., Shlomo, E., Halevy, A.H., and Weiss D. (2003). Promotion of Globularia sarcorphylla flowering by uniconazol, an inhibitor of gibberellin biosynthesis. Sci. Hortic. 98, 423–431.

  • Khademi, M., and Khosh-Khui, M. (1977). Effect of growth regulators on branching, flowering and fruit development of ornamental pepper (Capsicum annuum L.). J. Am. Soc. Hortic. Sci. 102, 796–798.

  • Kumar, R., and Singh, K. (2002). Effect of growth regulator and shoot tip pinching on carnation. J. Ornamental Hortic. 6, 134–136.

  • Kumar, R., and Singh, K. (2003). Regulating growth and flowering in Carnation through planting date, photo period, Gibberellic acid and pinching treatments. Haryana Hortic. Sci. 32, 69–72.

  • Larcher, F., Berruti, A., Gullino, P., and Scariot, V. (2011). Reducing peat and growth regulator input in camellia pot cultivation. Hortic. Sci. 38, 35–42.

  • Larson, R.A. (1980). Introduction to floriculture (New York, USA: Academic Press).

  • Lickfeldt, D.W., Gardner, D.S., Branham, B.E., and Voigt, T.B. (2001). Implications of repeated trinexapac-ethyl applications on Kentucky bluegrass. Agron. J. 93, 1164–1168.

  • Love, J.W. (1975). Vegetative growth. In A growing azaleas commercially, A.B. Kofranek, and R. Larson, eds. (University of California, United States, Division of Agriculture Science).

  • Mader, J.C., Emery, R.J.N., and Turnbull, C.G.N. (2003). Spatial and temporal changes in multiple hormone groups during lateral bud release shortly following apex decapitation of chickpea (Cicer arietinum) seedlings. Physiol. Plantarum 119, 295–308.

  • Malleshappa, H. (1984). Influence of pinching and CCC on growth and yield of China aster cv. Ostrich plume. M.Sc. Thesis, Dharwad, University of Agricultural Sciences in Dharwad.

  • Marosz, A., and Matysiak, B. (2005). Influence of growth retardants on growth and flower bud formation in Rhododendron and azalea. Dendrobiology 54, 35–40.

  • Matta, F.B. (1984). Effects of hand-pinching and dikegulac-sodium sprays on Capsicum annuum. HortScience 19, 284–285.

  • McCullough, P., Liu, H.B., McCarty, L.B., Whitwell, T., and Toler, J. (2006a). Nutrient allocation of ‘TifEagle’ Bermudagrasses influenced by trinexapac-ethyl. J. Plant Nutr. 29, 273–282.

  • McCullough, P.E., Liu, H.B., McCarty, L.B., Whitwell, T., and Toler, J.E. (2006b). Bermudagrass putting green growth, color, and nutrient partitioning influenced by nitrogen and trinexapac-ethyl. Crop Sci. 46, 1515–1525.

  • Meijon, M., Rodriguez, R., Canal, M.J., and Feito, I. (2009). Improvement of compactness and floral quality in azalea by means of application of plant growth regulators. Sci. Hortic. 119, 169–176.

  • Mousa, A. (2012). Effect of hand pinching, dikegulac-sodium, and gibberellic acid on chile pepper (Capsicum annuum). M.Sc. (Hortic.) Thesis, Mississippi, University of Mississippi State.

  • Mόller, D., and Leyser, O. (2011). Auxin, cytokinin and the control of shoot branching. Ann. Bot. 107, 1203–1212.

  • Nau, J. (1989). Ball Culture Guide. The encyclopedia of seed germination (West Chicago, Illinois: Ball Seed Co.).

  • Nelson, P.V. (1998). Greenhouse operation and management, 5th ed. (Upper Saddle River, N.J.: Prentice Hall).

  • Pathania, N.S., Sehgal, O.P., and Gupta, Y.C. (2000). Pinching for flower regulation in Sim Carnation. J. Ornam. Hortic. 3, 114–117.

  • Qian, Y.L., and Engelke, M.C. (1999). Influence of trinexapac-ethyl on diamond zoysiagrass in a shade environment. Crop Sci. 39, 202–208.

  • Rademacher, W. (2000). Growth retardants: Effects on gibberellins biosynthesis and other metabolic pathways. Annu. Rev. Plant Phys. 51, 501–531.

  • Rademacher, W. (2014). Prohexadione-Ca and Trinexapac-Ethyl: Similarities in structure but differences in biological action. Acta Hortic. 1042, 33–41.

  • Sawwan, J., and Samawi, M. (2000). Effect of pinching of plastic house grown spray-type carnation yield and yield distribution. Dirasat Agr. Sci. 27, 106–111.

  • Severmutlu, S., Mutlu, N., Gurbuz, E., Shearman, R.C., and Riordan, T.P. (2012). Effects of seasonal Trinexapac-ethyl application on warm-season turfgrass species growth under Mediterranean environment. Eur. J. Hortic. Sci. 77, 279–287.

  • Singh M.K., and Baboo, R. (2003). Response of N, K and pinching levels on growth and flowering in chrysanthemum. J. Ornam. Hortic. 6, 390–393.

  • Starman, T.W. (1993). Ornamental pepper growth and fruiting response to unicanozole depends on application time. HortScience 28, 917–919.

  • Stommel, J.R., and Griesbach, R. (2004). Capsicum annuum L. ‘Tangerine Dream’. HortScience 39, 448–449.

  • Tiwari, A., Offringa, R., and Heuvelink, E. (2012). Auxin-induced fruit set in Capsicum annuum L. requires downstream gibberellin biosynthesis. J. Plant Growth Regul. 31, 570–578.

  • Turnbull, G.N.C., Raymond, A.A.M., Dodd, C.I., and Morris, E.S. (1997). Rapid increases in cytokinin concentration in lateral buds of chickpea (Cicer arietinum L.) during release of apical dominance. Planta 202, 271–276.

  • Ubukata, M. (1999). Evaluation of one-half pinch method of spray carnation cultivation in Hokkaido. Bull. Hokkaido Prefectural Agricultural Experiment Stations 77, 39–43.

  • Watschke, T.L., and Dipaola, J.M. (1995). Plant growth regulators. Golf Course Mgt. 63, 59–62.

  • Whipker, B.E., McCall, I., and Gibson, J.L. (2000). Bonzi has advantages over sumagic as a growth regulator for ornamental pepper. Floriculture Research, NC State University Horticultural Research Series 146, 1–3.

  • Zhang, H., Wu, J., Zhang, Y., and Wang, K. (2014). Dissipation of trinexapac-ethyl and its metabolite in wheat field ecosystems and microbial degradation in soil. Int. J. Environ. An. Ch. 94, 1375–1387.

Received: 6 March 2015 | Revised: 17 July 2015 | Accepted: 2 October 2015 | Published: 21 December 2015 | Available online: 21 December 2015

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