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
., 2007 ), and leaf mineral accumulation ( Wu et al., 2008 ), but no information has been reported for nonheading Chinese cabbage. Plant height is one of the important agronomic traits for plant breeding in nonheading Chinese cabbage and is affected by
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
. ) ( Nemli et al., 2014 ), and heat tolerance in cowpea ( Lucas et al., 2013 ). Some of the major agronomic traits of interest in spinach are bolting, plant height, and leaf erectness. Bolting is an important trait to consider in relation to developing
medium; ( C ) phenotypes of nontransgenic control and the transgenic plants after 2 months cultured in Type II medium, from left to the right: nontransgenic control, transgenic lines (T-HF1,T-HF2, T-HF3, T-HF4, and T-HF5); ( D ) height of transgenic
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
these evaluations were based on data from one site over multiple years. Size categories based on plant height at maturity were first proposed by Egolf and Andrick (1978) . Johnson and Dix (1993) pointed out that “at maturity” is a vague term that
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
A research collaboration between Clemson Univ. and Mitsui Chemicals, Japan, has been established to develop and test photoselective greenhouse covers that can filter out far-red (FR) light and control plant height with minimal use of chemicals. The effects of polymethyl methacylate (PMMA) filters containing FR-intercepting dyes were evaluated on watermelon, pepper, chrysanthemum, and tomato to select an optimum dye concentration. As the dye concentration increased, FR interception increased, photosynthetic photon flux (PPF) decreased, and phytochrome photoequilibrium increased from 0.72 to 0.82. Light transmitted through photoselective filters reduced plant height effectively in all species tested. However, watermelon was the most responsive (50% height reduction) and chrysanthemum was the least responsive (20% height reduction) to filtered light. Tomato and peppers had an intermediate response. In watermelons, total shoot dry weight was reduced over 25% compared to the control plants, with a progressive decrease in shoot weight as the dye concentration increased. The specific stem dry weight was gradually reduced as the dye concentration increased. Specific leaf dry weight was slightly reduced under filters, suggesting that smaller plants as opposed to a reduction in dry matter production primarily caused total dry weight reduction. Light transmitted through filters reduced percentage dry matter accumulation into stems from 27% to 18% and increased dry matter accumulation into leaves from 73% to 82%. Photoselective filters are effective in controlling height similarly to chemical growth regulators. Considering the PAR reduction by increase in dye concentration, a dye concentration that gives a light reduction of 25% or 35% may be optimum for commercial development of photoselective films.