temperature conditions ( Garner and Björkman, 1996 ). Nevertheless, during ornamental plant production, the application of plant growth regulators (PGRs) is still the most commonly used tool for achieving an effective reduction in plant height ( Latimer, 1992
Easter lily is an important flowering potted crop in the United States, with a wholesale value over $26 million for the 15 largest-producing states ( U.S. Department of Agriculture, 2007 ). Plant height can reach up to 1 m and must be controlled to
drenches of flurprimidol have been effective at controlling plant height in several bulbous species, including calla lily [ Zantedeschia aethiopica ( Whipker et al., 2011b )], elephant ear ( Caladium ), daffodil ( Narcissus ), and oriental lily ( Lilium
leaves and attractive terminal or axillary lavender to purple spikes of flowers ( Riffle, 1998 ). However, without height control, firespike grows too tall exceeding the commercial requirements for potted plants. Thus, control of firespike stem elongation
Commercial nursery crop production in the United States involves the use of chemical plant growth regulators (PGRs) to control plant growth and height ( Hayashi et al., 2001 ; Latimer and Scoggins, 2012 ). Compact plants are easier to transplant
The interest in using nonchemical alternatives for growth control of horticultural crops has recently increased due to public concerns for food safety and environmental pollution. Several research teams around the world are investigating alternative growth control measures, such as genetic manipulation, temperature, water and nutrient management, mechanical conditioning, and light quality manipulation. This review discusses the recent developments in light quality manipulation as a nonchemical alternative for greenhouse plant height control.
, and Valent USA for financial aid and materials support, and to the greenhouse staff of the Kenneth Post Laboratory of Cornell University for plant care.
Blakely, Creekside Plants, Oologah, Okla., for their ingenuity and contribution of time, labor, and greenhouse space.
Growth and flowering of Ixia hybrids as potted plants can be controlled environmentally by cool preplant storage of corms, regulation of greenhouse forcing temperatures, and application of a growth retardant. Paclobutrazol applied as a preplant corm soak, a postemergent drench, or a postemergent spray in combination with a 2- to 4-week preplant storage of corms at 7 °C, and an 18 °C day/10 °C night forcing temperature produced attractive and marketable plants. Chemical name used: β-[(4-chlorophenyl)methyl]-α-(1,1-dimethylethyl)-1H-1,2,4-triazole-1-ethanol (paclobutrazol, Bonzi®).
regulate plant height and improve plant uniformity and can contribute to more accurate scheduling of flowering dates, meeting market requirements for plant height, and reduction of shipping costs. Although there are general guidelines suggesting the best