scholarly journals Efficacy of Ancymidol, Paclobutrazol, and Uniconazole on Growth of Tuberous-rooted Dahlias

HortScience ◽  
1996 ◽  
Vol 31 (4) ◽  
pp. 655d-655
Author(s):  
Brian E. Whipker ◽  
P. Allen Hammer
Keyword(s):  
Plant Growth ◽  
Plant Height ◽  
Growth Retardant ◽  
Height Control ◽  
Potted Plants

Plant growth retardant (PGR) media drench treatments (in mg a.i./pot) of ancymidol at 0.5, 1.0, 2.0, 4.0, or 8.0; paclobutrazol at 1.0, 2.0, 4.0, 8.0, or 16.0; uniconazole at 0.5, 1.0, 2.0, 4.0, or 8.0 were applied to tuberous-rooted dahlias to compare their effectiveness as a chemical height control. All paclobutrazol, ancymidol, and uniconazole rates applied significantly reduced `Red Pigmy' plant height by 21% or greater compared to the nontreated control. Excessively short plants resulted from uniconazole and ancymidol drench rates ≥1.0 mg. `Red Pigmy', a less vigorous cultivar, were acceptable as potted-plants with paclobutrazol rates of 2.0 to 4.0 mg, 0.25 to 0.5 mg of uniconazole, or 0.5 mg of ancymidol. All paclobutrazol, ancymidol, and uniconazole rates significantly reduced `Golden Emblem' plant height by ≥11% when compared to the nontreated plants. Excessively short plants resulted from paclobutrazol drench rates of 16.0 mg, uniconazole rates of 2.0 mg and for ancymidol drenches ≥4.0 mg. `Golden Emblem', the more vigorous cultivar, were acceptable as potted-plants with paclobutrazol rates of 4.0 to 8.0 mg, 0.5 to 1.0 mg of uniconazole, or 2.0 mg of ancymidol.

scholarly journals Efficacy of Ancymidol, Paclobutrazol, and Uniconazole on Growth of Tuberous-rooted Dahlias

1997 ◽  
Vol 7 (3) ◽  
pp. 269-273 ◽  
Author(s):  
Brian E. Whipker ◽  
P. Allen Hammer
Keyword(s):  
Plant Growth ◽  
Plant Height ◽  
Untreated Control ◽  
Growth Retardant ◽  
Canopy Height ◽  
Height Control ◽  
Total Height ◽  
Potted Plants ◽  
Total Plant ◽  
Leaf Canopy

Plant growth retardant (PGR) substrate drench treatments (mg a.i./1.5-L pot) of ancymidol at doses of 0.5 to 8, paclobutrazol from 1 to 16, and uniconazole from 0.125 to 2 were applied to tuberous-rooted dahlias (Dahlia variabilis Willd.) to compare their effectiveness for controlling height. When the first inflorescence opened, the number of days from potting until flowering, leaf canopy height, inflorescence height above the foliage, and plant diameter were recorded. Total height control achieved using PGRs was primarily due to reduced inflorescence height, rather than leaf canopy height. Paclobutrazol, ancymidol, and uniconazole at all doses reduced total plant height of the less-vigorous `Red Pigmy' by >21% compared to the untreated control, with a height of 43.5 cm for the untreated control plants. Marketable potted plants were produced with doses of 2 to 4 mg of paclobutrazol, 0.25 to 0.5 mg of uniconazole, or 0.5 mg of ancymidol. All paclobutrazol, ancymidol, and uniconazole doses reduced total plant height of the more-vigorous `Golden Emblem' by >11% compared to the untreated control, with a height of 82.1 cm for the untreated control. Marketable potted plants were produced with 4 to 8 mg of paclobutrazol, 0.5 to 1 mg of uniconazole, or 2 mg of ancymidol.

scholarly journals Pot Sunflower Growth and Flowering Responses to Foliar Applications of Daminozide, Paclobutrazol, and Uniconazole

HortScience ◽  
1997 ◽  
Vol 32 (3) ◽  
pp. 438D-438
Author(s):  
Brian E. Whipker ◽  
Shravan Dasoju
Keyword(s):  
Plant Growth ◽  
Helianthus Annuus ◽  
Plant Height ◽  
Foliar Spray ◽  
Growth Retardant ◽  
Height Control ◽  
Foliar Sprays ◽  
Treatment Interaction ◽  
Total Plant

Plant growth retardant (PGR) foliar spray treatments (mg•liter–1) of daminozide at 1000 to 16,000; paclobutrazol from 5 to 80; and uniconazole from 2 to 32 were applied to `Pacino' pot sunflowers (Helianthus annuus) to compare their effectiveness at chemical height control. When the first inflorescence opened, the number of days from seeding until flowering, total plant height measured from the pot rim to the top of the inflorescence, inflorescence diameter, and plant diameter were recorded. Total plant height, plant diameter, inflorescence diameter, and days until flowering were significant for the PGR treatment interaction. Marketable-sized plants grown in the 1.2-liter pots were produced with uniconazole concentrations between 16 and 32 mg•liter–1 or with daminozide concentrations between 4000 and 8000 mg•liter–1. Paclobutrazol foliar sprays up to 80 mg•liter–1 had little effect and higher concentrations or medium drench treatments should be considered.

scholarly journals Vegetatively Propagated Geraniums Respond Similarly to Drench Applications of Paclobutrazol or Uniconazole

2000 ◽  
Vol 10 (1) ◽  
pp. 151-153 ◽  
Author(s):  
Brian E. Whipker ◽  
Shravan K. Dasoju ◽  
Michael R. Evans
Keyword(s):  
Plant Growth ◽  
Plant Height ◽  
Growth Regulator ◽  
Plant Growth Regulator ◽  
Canopy Height ◽  
Height Control ◽  
Total Height ◽  
Potted Plants ◽  
Total Plant ◽  
Leaf Canopy

Drench applications of paclobutrazol or uniconazole were applied at doses of 0, 0.0025, 0.005, 0.01, 0.02, or 0.04 mg a.i./pot (28,350 mg = 1.0 oz) to vegetatively propagated `Aurora', `Medallion Dark Red', and `Pink Satisfaction' geranium (Pelargonium ×hortorum L.H. Bailey). Geranium total plant height, leaf canopy height, and plant diameter responded similarly to drench applications of either paclobutrazol or uniconazole. There was a significant quadratic relationship between plant growth regulator (PGR) dose and total plant height and leaf canopy height for `Aurora' and `Medallion Dark Red', with total plant height and leaf canopy height being shorter as paclobutrazol or uniconazole doses increased up to 0.02 mg. However, doses of ≥0.02 mg had little additional effect on total plant height and leaf canopy height. Most of the total height control achieved by the use of PGRs was primarily due to a reduction of leaf canopy height, rather than inflorescence height. Doses of 0.005 to 0.01 mg of either PGR produced marketable sized potted plants of `Medallion Dark Red' and `Pink Satisfaction'. `Aurora', which was the most vigorous cultivar, required doses of 0.01 or 0.02 mg of either paclobutrazol or uniconazole to produce marketable sized potted plants.

scholarly journals Efficacy of Paclobutrazol Drenches on Growth of Potted Sunflowers Grown in 16.5-cm Pots

HortScience ◽  
1997 ◽  
Vol 32 (3) ◽  
pp. 438C-438
Author(s):  
Shravan K. Dasoju ◽  
Brian E. Whipker
Keyword(s):  
Plant Growth ◽  
Helianthus Annuus ◽  
Plant Height ◽  
Untreated Control ◽  
Growth Retardant ◽  
Height Control ◽  
Pot Size ◽  
Optimum Height ◽  
Flower Diameter ◽  
Pot Plant

Drench applications of plant growth retardant paclobutrazol were applied at 2, 4, 8, 16, or 32 mg a.i./pot, plus an untreated control to pot sunflowers (Helianthus annuus cv. `Pacino') to determine its effect as a chemical height control. All paclobutrazol concentrations applied significantly reduced plant height by »27% when compared to the untreated control, but excessively short plants were observed at 16 and 32 mg a.i./pot. Plant diameter was also significantly decreased by »16% at 2 and 4 mg a.i./pot of paclobutrazol, when compared to the untreated control. Flower diameter decreased by »4% at 2 and 4 mg a.i./pot of paclobutrazol, but only concentrations ≥4 mg a.i./pot were significantly different from the untreated control. Paclobutrazol concentrations had no effect on days from potting to flowering. Drench concentrations of 2 and 4 mg a.i./pot of paclobutrozol produced optimum height control in relation to 16.5-cm-diameter pot size used.

scholarly journals Potted Sunflower Growth and Flowering Responses to Foliar Applications of Daminozide, Paclobutrazol, and Uniconazole

1998 ◽  
Vol 8 (1) ◽  
pp. 86-88 ◽  
Author(s):  
Brian E. Whipker ◽  
Shravan Dasoju
Keyword(s):  
Plant Growth ◽  
Plant Height ◽  
Foliar Spray ◽  
Growth Retardant ◽  
Height Control ◽  
Foliar Sprays ◽  
Significant Difference ◽  
Main Effect ◽  
Total Plant ◽  
Pollen Number

Plant growth retardant (PGR) foliar sprays (in mg·L−1) of daminozide at concentrations from 1,000 to 16,000; paclobutrazol from 5 to 80; and uniconazole from 2 to 32 were applied to `Pacino' potted sunflowers (Helianthus annuus L.) to compare their effectiveness at chemical height control. Plants were grown in 650-mL or 1.2-L pots. When the first inflorescence started to shed pollen, number of days from seeding until anthesis, total plant height measured from the pot rim to the top of the inflorescence, inflorescence diameter, and plant diameter were recorded. There was no significant difference in plant height between `Pacino' plants grown in 650-mL or 1.2-L pots. Total plant height, plant diameter, inflorescence diameter, and days until flowering were significant for the PGR treatment main effect. Marketable-sized plants grown in the 1.2-L pots were produced with uniconazole concentrations from 16 to 32 mg·L−1 or with daminozide concentrations from 4,000 to 8,000 mg·L−1. Paclobutrazol foliar sprays up to 80 mg·L−1 had little effect, and higher foliar spray concentrations or substrate drench treatments may be needed to effectively control height.

scholarly journals Substrate Drenches Containing Flurprimidol Suppress Height of ‘Nellie White’ Easter Lilies

2012 ◽  
Vol 22 (2) ◽  
pp. 164-168 ◽  
Author(s):  
Christopher J. Currey ◽  
Roberto G. Lopez ◽  
Brian A. Krug ◽  
Ingram McCall ◽  
Brian E. Whipker
Keyword(s):  
Plant Growth ◽  
Plant Height ◽  
Lilium Longiflorum ◽  
Growth Retardant ◽  
Flower Number ◽  
Height Control ◽  
Easter Lily ◽  
The Cost ◽  
Economical Alternative ◽  
Pot Plant

The objective of this research was to quantify how flurprimidol substrate drenches applied to ‘Nellie White’ easter lilies (Lilium longiflorum) affected height at flowering, time to flower, and flower number. In Expt. 1, size 9/10 ‘Nellie White’ easter lilies were treated with a 4-fl oz drench applied to the surface of the substrate when shoots were ≈3 inches tall providing 0.0, 0.02, 0.04, 0.08, 0.16, or 0.24 mg flurprimidol per pot or 0.03 or 0.06 mg uniconazole per pot. In Expt. 2, size 10/12 ‘Nellie White’ easter lilies were treated with 4-fl oz drenches applied to the surface of the substrate when shoots were ≈3 inches tall providing 0.0, 0.01, 0.02, 0.04, 0.06, or 0.08 mg flurprimidol per pot. In Expt. 1, plants treated with flurprimidol or uniconazole were up to 38.9 cm (59%) shorter than untreated plants, while time to flower and flower number remained unaffected by plant growth retardant (PGR) treatments. In Expt. 2, as the amount of flurprimidol increased from 0.01 to 0.08 mg/pot, plant height was suppressed linearly (r2 = 0.63), by up to 23.2 cm (28%), while time to flower and flower number remained unaffected. Additionally, the chemical cost for drenches containing flurprimidol is less than the cost of uniconazole required to achieve comparable height control. Flurprimidol substrate drenches appear to be an effective and economical alternative to control easter lily height.

scholarly journals 258 Pampas Grass (Cortaderia argentea) Response to Ancymidol, Paclobutrazol, and Uniconazole Substrate Drenches

HortScience ◽  
1999 ◽  
Vol 34 (3) ◽  
pp. 486E-486
Author(s):  
James Sellmer ◽  
Craig R. Adkins ◽  
Ingram McCall ◽  
Brian Whipker
Keyword(s):  
Plant Growth ◽  
Plant Height ◽  
Active Ingredient ◽  
Untreated Control ◽  
Residual Effect ◽  
Growth Retardant ◽  
Dose Effect ◽  
Greenhouse Production ◽  
Height Control ◽  
Linear Dose

Plant growth retardant (PGR) substrate drenches (in milligrams active ingredient) of ancymidol at 0.25, 0.5, 1, 2, or 4; paclobutrazol at 1, 2, 4, 8, or 16; and uniconazole at 0.25, 0.5, 1, 2, or 4 were applied to pampas grass (Cortaderia argentea Nees) to compare their effectiveness at chemical height control during greenhouse forcing and evaluate the residual effect on plant growth in the landscape. Cortaderia argentea plant height exhibited a quadratic dose response to paclobutrazol and uniconazole, while ancymidol-treated plants showed a linear dose effect. During greenhouse production, all rates of uniconazole reduced plant height by 56% to 71% compared to the untreated control, whereas paclobutrazol and ancymidol treatments reduced plant height by 14% to 61% and 0% to 34%, respectively. Severe height retardation was evident at 2 mg of uniconazole. By week 5 in the field all plants treated with uniconazole, paclobutrazol doses of 4, 8, or 16 mg, and with 4 mg of ancymidol were shorter than the untreated control. By week 24 in the field, all plants exhibited similar heights except plants treated with uniconazole at 1, 2, or 4 mg remained shorter than the untreated control. In conclusion, each PGR was effective in controlling plant height of Cortaderia argentea during greenhouse forcing. Furthermore, plants treated with low to moderate rates of ancymidol or paclobutrazol grew out of the regulating effect by week 5 in the landscape. These results demonstrate that PGR can be effectively and economically employed in the production of Cortaderia argentea.

scholarly journals 017 GROWTH REGULATOR EFFECTS ON HEIGHT CONTROL OF POTTED MUSSAENDA QUEEN SIRIKIT

HortScience ◽  
1994 ◽  
Vol 29 (5) ◽  
pp. 430a-430
Author(s):  
Christopher S. Cramer ◽  
Mark P. Bridgen
Keyword(s):  
Plant Height ◽  
Growth Regulators ◽  
Growth Habit ◽  
The United States ◽  
The Philippines ◽  
Height Control ◽  
Potted Plants ◽  
Plant Culture ◽  
Application Methods ◽  
Ornamental Shrub

Mussaenda, a tropical ornamental shrub developed in the Philippines is being examined as a potential greenhouse potted crop in the United States. Showy sepals of white, picotee, pink or red and fragrant, yellow flowers make Mussaenda an attractive patted plans however, the profuse upright growth habit of some Mussaenda cultivars is undesirable for pot plant culture. With this in mind experiments were conducted to determine the effects of three growth regulators at two concentrations each, as well as the application method and the number of applications on Mussaenda plant height. Three growth regulators, daminozide (B-Nine), ancymidol (A-Rest), and paclobutrazol (Bonzi) were applied at two commercially recommended rates and two application methods (spray or drench). The treatment were daminozide at 2500 ppm and 5000 ppm (spray), ancymidol at 33 and 66 ppm (spray) and at 0.25 and 0.50 mg/pot (drench), and paclobutrazol at 25 and 50 ppm (spray) and at 0.125 and 0.25 mg/pot (drench). In subsequent experiments, the same growth regulators were applied with an increase in concentration and either two or three applications. The treatments were daminozide at 5000 ppm (spray), ancymidol at 66 and 132 ppm (spray) and at 0.50 and 1.0 mg/pot (drench), and paclobutrazol at 50 and 100 ppm (spray) and at 0.25 and 0.50 mg/pot (drench). The most attractive potted plants were produced with two applications of daminozide at 5000 ppm or two applications of ancymidol at 0.5 mg/pot (drench). Higher concentrations or additional applications excessively reduced plant height. Three spray applications of 132 ppm ancymidol also produced an attractive potted plant. Paclobutrazol sprays or drenches at any concentration or application number were ineffective for reducing Mussaenda `Queen Sirikit' plant height.

scholarly journals End-of-day Lighting with Different Red/Far-red Ratios Using Light-emitting Diodes Affects Plant Growth of Chrysanthemum × morifolium Ramat. ‘Coral Charm’

HortScience ◽  
2007 ◽  
Vol 42 (7) ◽  
pp. 1609-1611 ◽  
Author(s):  
Janni Bjerregaard Lund ◽  
Theo J. Blom ◽  
Jesper Mazanti Aaslyng
Keyword(s):  
Plant Growth ◽  
Plant Height ◽  
Light Quality ◽  
Light Emitting Diodes ◽  
Dry Weight ◽  
Chrysanthemum Morifolium ◽  
Lateral Side ◽  
Light Emitting ◽  
Potted Plants ◽  
Future Production

Controlling plant height without the use of plant growth retardants is one of the goals in future production of potted plants. Light quality with a low red to far-red ratio (R:FR) increases plant height. In this trial, the effects of light quality [R:FR ratio of 0.4, 0.7, and 2.4 (R = 600–700 nm, FR = 700–800 nm)] at the end of day were investigated on potted chrysanthemums using growth chambers. After a 9-h photoperiod, the 30-min end-of-day lighting was provided by light-emitting diodes at low irradiance by maintaining either red = 1 μmol·m−2·s−1 (Rcon) or far-red = 1 μmol·m−2·s−1(FRcon). After 3 weeks of end-of-day lighting, plants given the lowest end-of-day ratios (R:FR of 0.4 or 0.7) were taller than control plants (R:FR = 2.4). For low ratios of R:FR (0.4), the actual intensities of R and FR did not affect plant height, whereas for higher ratios of R:FR (0.7 and 2.4), plant height was greater for FRcon than for Rcon. Leaf area of the lateral side shoots was lower for plants treated with an R:FR of 0.4 compared with those of controls. Dry weight, stem diameter, number of internodes, and number of lateral branches were unaffected by the end-of-day ratio.

scholarly journals Effects of Pinching, Number of Cuttings per Pot, and Plant Growth Regulators on Height Control of Purple Firespike

2015 ◽  
Vol 25 (1) ◽  
pp. 71-75 ◽  
Author(s):  
Amir Rezazadeh ◽  
Richard L. Harkess
Keyword(s):  
Plant Growth ◽  
Leaf Area ◽  
Plant Height ◽  
Plant Growth Regulators ◽  
Growth Regulators ◽  
Stem Elongation ◽  
Dry Weight ◽  
Maximum Height ◽  
Height Control ◽  
Leaf Dry Weight

Purple firespike (Odontonema callistachyum), native to Central America, has potential for use as a new flowering potted plant. The effects of number of pinches (zero, one, or two) and number of cuttings (one, two, or three) per 6-inch pot were evaluated on the control of plant height. Plant height was suppressed as the pinch number increased. The greatest reduction was recorded with one cutting per pot and two pinches. The maximum number of branches per pot was recorded with two pinches and three cuttings per pot. In a second experiment, plant growth regulators (PGR) were also tested for efficacy of height control; 2 weeks after pinching, foliar sprays of paclobutrazol, flurprimidol, daminozide, chlormequat, and a tank-mix of daminozide + chlormequat or media drenches of paclobutrazol, uniconazole, or flurprimidol were applied. Plant height, leaf area, and leaf dry weight were recorded at 3, 6, and 9 weeks after PGR application. Maximum height control was obtained with uniconazole drench at 8 ppm, resulting in plants 22 cm tall, 61% shorter than the untreated control (56 cm); however, it resulted in severe leaf distortion. Plant height was 56% and 46% shorter than the control using drenches of paclobutrazol at 30 ppm and flurprimidol at 15 ppm, respectively. Daminozide spray at 2000 ppm and tank-mix of daminozide + chlormequat at 4500/1500 ppm suppressed stem elongation by 20.3% and 19%, respectively. Plants treated with paclobutrazol drench at 30 ppm reduced leaf area and leaf dry weight compared with other PGRs. Chlormequat spray at tested concentrations was ineffective for controlling firespike plant growth. The most attractive potted plants were produced using a drench application of paclobutrazol at 10 or 15 ppm.

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