Trinexapac-ethyl modifies plant architecture of ornamental pepper

Summary 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.