scholarly journals Zonal Geranium Growth and Flowering Response to Chemical Growth Retardants

HortScience ◽  
1995 ◽  
Vol 30 (4) ◽  
pp. 865F-866
Author(s):  
Brian E. Whipker ◽  
P. Allen Hammer
Keyword(s):  
Plant Growth ◽  
Untreated Control ◽  
Total Concentration ◽  
Growth Retardant ◽  
Canopy Height ◽  
Growth Retardants ◽  
Height Control ◽  
Flowering Response ◽  
Foliar Sprays ◽  
Treatment Interaction

Chemical plant growth retardant (PGR) treatments (mg·liter–1) were applied as foliar sprays to three zonal geranium cultivars: chlormequat at 1500, applied two, three, and four times, a combination of chlormequat at 750 and daminozide at 1250, applied one and two times, and paclobutrazol applied once at 5, 10, 20, and 30; twice at 5, 10, and 15; and three times at 5, plus an untreated control. Two paclobutrazol drench treatments at 0.1 and 0.25 mg a.i. per pot were also applied. The results of the PGR applications were significant at the cultivar × treatment interaction for leaf canopy height and plant diameter. Paclobutrazol rates of 10 to 15 mg·liter–1 resulted in acceptable height control for `Medallion Dark Red' and `Aurora'. `Pink Satisfaction' is a less vigorous cultivar and lower paclobutrazol rates of 5 to 10 mg·liter–1 were more suitable. When the total concentration of the single and multiple applications were compared, no additional height control was realized with the multiple applications of paclobutrazol.

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 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 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 Comparison of Flurprimidol to Ancymidol, Paclobutrazol, and Uniconazole for Tulip Height Control

2005 ◽  
Vol 15 (2) ◽  
pp. 370-373 ◽  
Author(s):  
Brian A. Krug ◽  
Brian E. Whipker ◽  
Ingram McCall ◽  
John M. Dole
Keyword(s):  
Plant Growth ◽  
Plant Height ◽  
Growth Regulator ◽  
Plant Growth Regulator ◽  
Untreated Control ◽  
Cost Effective ◽  
Height Control ◽  
Foliar Sprays ◽  
Cost Effective Method ◽  
The Cost

Preplant bulb soaks of ancymidol, flurprimidol, paclobutrazol, and uniconazole; foliar sprays of flurprimidol; and substrate drenches of flurprimidol, paclobutrazol, and uniconazole were compared for height control of `Prominence' tulips (Tulipa sp.). Height control was evaluated at anthesis in the greenhouse and 10 days later under postharvest conditions. Substrate drenches of ancymidol, flurprimidol, and paclobutrazol resulted in adequate control using concentrations of 0.5, 0.5, and 1 mg/pot a.i. (28,350 mg = 1 oz), respectively. At these concentrations, ancymidol drenches cost $0.06/pot and paclobutrazol drenches $0.03/pot. Since flurprimidol is not yet available and no price is available, growers will need to assess the cost compared to ancymidol and paclobutrazol. Flurprimidol foliar sprays at <80 mg·L–1 (ppm) were ineffective in controlling height during greenhouse forcing, but during postharvest evaluation 80 mg·L–1 resulted in 14% shorter plants than the untreated control. Preplant bulb soaks of flurprimidol, paclobutrazol, and uniconazole at concentrations of 25, 50, and 10 mg·L–1, respectively, effectively controlled plant height. Preplant plant growth regulator soaks are a cost-effective method of controlling plant height of tulips because of the limited amount of chemical required to treat a large quantity of bulbs.

scholarly journals Response of Potted Sunflower Cultivars to Daminozide Foliar Sprays and Paclobutrazol Drenches

2000 ◽  
Vol 10 (1) ◽  
pp. 209-211 ◽  
Author(s):  
Brian E. Whipker ◽  
Ingram McCall
Keyword(s):  
Plant Height ◽  
Untreated Control ◽  
Plant Density ◽  
Control Plant ◽  
Economic Advantage ◽  
Growth Retardant ◽  
Percentage Reduction ◽  
Teddy Bear ◽  
Height Control ◽  
Foliar Sprays

Plant growth retardant (PGR) foliar sprays of daminozide at 4,000 or 8,000 mg·L-1 (ppm) and paclobutrazol drenches of 2 or 4 mg a.i. per pot were applied to `Big Smile', `Pacino', `Sundance Kid', `Sunspot', and `Teddy Bear' pot sunflowers (Helianthus annuus L.) to compare their chemical height control. Plant height varied among the cultivars due to genetic variation. The percentage reduction in plant height from the untreated control only was significant at the PGR level, indicating similar responses of all five cultivars to each PGR rate. Paclobutrazol drenches at 2 mg and daminozide foliar sprays at 4,000 or 8,000 mg·L-1 reduced plant height by about 24% when compared to the control. Paclobutrazol drenches at 4 mg produced plants that were 33% shorter than the control. Plant diameter of `Big Smile', `Pacino', or `Sundance Kid' was unaffected by daminozide, whereas `Sunspot' plants were smaller than the controls. Paclobutrazol drenches at 2 or 4 mg decreased plant diameter for all cultivars except `Teddy Bear', with the reduction being greater as paclobutrazol drench rates increased. The number of inflorescence buds increased by ≥18% with the use of daminozide sprays, while paclobutrazol drenches at 2 or 4 mg had no effect when compared to the untreated control. Paclobutrazol drenches of 2 or 4 mg offer the economic advantage to growers of increased plant density on greenhouse benches, while plants treated with daminozide had an increased bud count but would require a greater amount of bench space.

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 Efficacy of Plant Growth Retardants as Preplant Bulb Dips for Height Control in LA and Oriental Hybrid Lilies

2002 ◽  
Vol 12 (3) ◽  
pp. 426-431 ◽  
Author(s):  
Anil P. Ranwala ◽  
Garry Legnani ◽  
Mary Reitmeier ◽  
Barbara B. Stewart ◽  
William B. Miller
Keyword(s):  
Plant Growth ◽  
Effective Means ◽  
Lilium Longiflorum ◽  
Growth Retardant ◽  
Growth Retardants ◽  
Height Control ◽  
Commercial Plant ◽  
Leaf Yellowing ◽  
Plant Growth Retardants ◽  
High Concentrations

We evaluated preplant bulb dips in three commercial plant growth retardants [ancymidol (A-Rest), paclobutrazol (Bonzi), and uniconazole (Sumagic)] for height control in seven oriental hybrid lily (Lilium) cultivars (Aubade, Berlin, Casa Blanca, Muscadet, Sissi, Star Gazer, and Tom Pouce), and seven LA-hybrid lily [hybrids resulting from crosses between easter lily (Lilium longiflorum) and Asiatic hybrids] cultivars (Aladdin's Dazzle, Best Seller, Cebeco Dazzle, Royal Dream, Royal Parade, Royal Perfume, and Salmon Classic) grown in containers. A 1-min dip into a range of concentrations of each product was used to determine the optimum concentrations for height control. The results indicate that bulb dips, especially with uniconazole and paclobutrazol, can be a highly effective means of height control in hybrid lilies. Cultivars varied in their response to growth retardant treatments. In general, LA-hybrid lilies were much more responsive to the growth retardant treatments than oriental hybrids and required lower rates for comparable height control. Delays in flowering, increased bud abortion and leaf yellowing were observed only with high concentrations of uniconazole or paclobutrazol where the height reduction was also too excessive for a commercially acceptable crop.

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 Plant Growth Retardant Application to Achillea x ‘Coronation Gold’ and Gaura lindheimeri ‘Corrie's Gold’

2000 ◽  
Vol 18 (3) ◽  
pp. 149-153
Author(s):  
Stephanie E. Burnett ◽  
Gary J. Keever ◽  
Charles H. Gilliam ◽  
J. Raymond Kessler ◽  
Charles Hesselein
Keyword(s):  
Plant Growth ◽  
Untreated Control ◽  
Growth Suppression ◽  
Effective Concentration ◽  
Growth Retardant ◽  
Growth Retardants ◽  
Herbaceous Perennials ◽  
Quality Ratings ◽  
Plant Growth Retardants ◽  
Delayed Flowering

Abstract In two experiments conducted under nursery conditions in 1998 and 1999, the herbaceous perennials, Achillea x ‘Coronation Gold’ and Gaura lindheimeri ‘Corrie's Gold’ were treated with one of four plant growth retardants (PGRs): B-Nine at 2,500, 5,000, or 7,500 ppm; Bonzi at 33, 66, or 99 ppm; Cutless at 50, 100, or 150 ppm; Pistill at 500 or 1,000 ppm; or left untreated. Only Pistill delayed flowering of achillea while Bonzi and Cutless accelerated flowering of achillea. In 1998, B-Nine provided little growth suppression of achillea; however in 1999, when plants were pruned just prior to treatment and thus less reproductively developed, height at the most effective concentration of 7,500 ppm was reduced 33% compared to untreated plants over the duration of the experiment. At the most effective concentration of 99 ppm, Bonzi retarded growth 15% and 31%, over the duration of the experiment, while Cutless at 150 ppm suppressed growth 21% and 46% in 1998 and 1999, respectively, compared to an untreated control. Plants treated with the most effective concentration of Pistill were 13% and 21% shorter than non-treated plants over the duration of the experiment in 1998 and 1999, respectively. However, in 1998 quality ratings of Pistill-treated plants were lower than for control plants, and the duration of control was shorter than with B-Nine, Bonzi, or Cutless in 1999. Only Cutless provided consistent growth suppression of gaura; plants treated with the most effective concentration of 150 ppm were an average of 19% smaller at 60 days after treatment (DAT) in 1998 and 13% smaller than control plants from 28 to 70 DAT in 1999. B-Nine and Pistill provided more transitory control. In 1999, the most effective concentration of B-Nine suppressed growth 9% from 28 to 56 DAT. Plants treated with the most effective concentration of Pistill of 500 ppm averaged 23% smaller at 14 and 28 DAT than control plants. Application of Pistill delayed flowering 11 to 13 days in 1998.

scholarly journals Comparison of Flurprimidol to Ethephon, Paclobutrazol, and Uniconazole for Hyacinth Height Control

2005 ◽  
Vol 15 (4) ◽  
pp. 872-874 ◽  
Author(s):  
Brian A. Krug ◽  
Brian E. Whipker ◽  
Ingram McCall ◽  
John M. Dole
Keyword(s):  
Plant Height ◽  
Untreated Control ◽  
Cost Effective ◽  
Height Control ◽  
Foliar Sprays ◽  
Cost Effective Method ◽  
Hyacinthus Orientalis

Preplant bulb soaks of flurprimidol, paclobutrazol, and uniconazole; foliar sprays of ethephon and flurprimidol; and substrate drenches of flurprimidol were compared for height control of `Anna Marie' hyacinths (Hyacinthus orientalis). Preplant bulb soak concentrations of flurprimidol and paclobutrazol were from 25 to 400 mg·L-1, and uniconazole from 5 to 80 mg·L-1. Height control was evaluated at anthesis and 11 days later under postharvest conditions. Ethephon (250 to 2000 mg·L-1) and flurprimidol (5 to 80 mg·L-1) foliar sprays were ineffective. Flurprimidol (0.25 to 4 mg/pot) drenches had no effect during forcing, but controlled postharvest height at concentrations ≥0.25 mg/pot a.i. with at least 4% shorter plants than the untreated control. Preplant bulb soaks resulted in height control with flurprimidol ≥25 mg·L-1, paclobutrazol ≥100 mg·L-1, and uniconazole ≥40 mg·L-1; having at least 9%, 6%, and 19%, respectively, shorter plants than the untreated control. Based on our results, flurprimidol preplant bulb soaks have a greater efficacy than either uniconazole or paclobutrazol. Preplant PGR soaks are a cost-effective method of controlling plant height of hyacinths because of the limited amount of chemical required to treat a large quantity of bulbs.

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