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

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.

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EFFECT OF DAMONOZIDE, ANCYMIDOL AND PACLBUTRAZOL ON HEIGHT CONTROL OF POTTED MUSSAENDA

HortScience ◽

10.21273/hortsci.28.4.257a ◽

1993 ◽

Vol 28 (4) ◽

pp. 257A-257

Author(s):

Christopher S. Cramer ◽

Mark P. Bridgen

Keyword(s):

Plant Height ◽

Growth Regulators ◽

The United States ◽

The Philippines ◽

Ornamental Plant ◽

Single Application ◽

Height Control ◽

Plant Culture ◽

Dark Green ◽

Dark Pink

Mussaenda, a tropical, hybrid ornamental plant from India and the Philippines, is being evaluated as a potential greenhouse ported crop in the united States. Showy sepals of white, picotee (White with rosy edges), light pink, dark pink, or red complemented by fragrant, yellow flowers and dark green, pubescent foliage make Mussaenda a very attractive potted plant. However, sometimes the height of Mussaenda is unsuitable for pot plant culture. With the use of chemical growth regulators. plant height is reduced thus making Mussaenda a more feasible potted crop. In the summer of 1992, a growth regulator study was conducted to evaluate three growth regulators and concentrations capable of reducing plant height in Mussaenda. Daminozide (B-Nine SP), ancymidol (A-Rest), or paclobutrazol (Bonzi) was applied at two concentrations each. Daminozide was tested as a spray at 2500 ppm and 5000 ppm. Ancymidol was applied as a spray at 33 ppm and 66 ppm or as a drench at 0.25 mg/pot and 0.50 mg/pot. Paclobutrazol was tested as a spray at 25 ppm and 50 ppm or as a drench at 0.125 mg/pot and 0.25 mg/pot. Growth regulators were applied as a single application or a double application with two weeks separating applications. Daminozide at 2500 ppm and 5000 ppm was most effective in controlling plant height. Ancymidol as a drench at 0.25 mg/pot and 0.50 mg/pot was also effective in plant height control. Two applications of these growth regulators were more effective in controlling plant height than a single application.

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Effects of plant growth regulators in heliconia ‘Red Opal’

Ornamental Horticulture ◽

10.14295/oh.v22i3.947 ◽

2016 ◽

Vol 22 (3) ◽

pp. 301

Author(s):

Ana Cecilia Ribeiro de Castro ◽

Fernando José Hawerroth ◽

Carlos Alberto Kenji Taniguchi ◽

Tiago Freitas Silva ◽

Nazaré Suziane Soares

Keyword(s):

Leaf Area ◽

Plant Height ◽

Growth Regulators ◽

Growth Regulator ◽

Block Design ◽

Dry Mass ◽

Potted Plants ◽

Randomized Block Design ◽

Number Of Leaves ◽

One Year

The objective of this study was to evaluate growth regulators with purpose of reducing the size of heliconia ‘Red Opal’ potted plants. The experiment was carried out in randomized block design with five treatments (trinexapac-ethyl and paclobutrazol at rates of 37.5 and 75.0 mg of active ingredient per pot and control without growth regulator) and five replicates. The treatments were applied 40 days after planting the rhizomes in pots filled with soil. Thirty and 150 days after the growth regulator application, plant height, number of leaves and shoots, petioles length and leaf area were evaluated. One year after planting the rhizomes in pots the number of inflorescence and leaves (leaves, sheathing leaf bases and inflorescences) and rhizomes (rhizomes and roots) dry mass were determined. Trinexapac-ethyl had no differences compared to the control in any of the variables evaluated. Paclobutrazol proved effective in reducing plant height, leaf area and petiole length and increase in number of leaves and shoots but the effect was temporary. Also, it did not affect the inflorescences production and leaves and rhizomes dry mass. Paclobutrazol is efficient to promote height reduction and to increase the number of shoots in heliconia ‘Red Opal’ potted plants without affect the inflorescence formation but its effects is temporary.

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

HortTechnology ◽

10.21273/horttech.25.1.71 ◽

2015 ◽

Vol 25 (1) ◽

pp. 71-75 ◽

Cited By ~ 2

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

HortTechnology ◽

10.21273/horttech.10.1.151 ◽

2000 ◽

Vol 10 (1) ◽

pp. 151-153 ◽

Cited By ~ 3

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.

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Flurprimidol and Paclobutrazol Substrate Drenches on Potted Pineapple Lily

HortTechnology ◽

10.21273/horttech04054-18 ◽

2018 ◽

Vol 28 (4) ◽

pp. 445-449

Author(s):

Shawn D. Lyons ◽

William B. Miller ◽

H. Christian Wien ◽

Neil S. Mattson

Keyword(s):

Plant Growth ◽

Plant Height ◽

Plant Growth Regulators ◽

Growth Regulators ◽

Production Time ◽

Crop Quality ◽

Height Control ◽

Application Rates ◽

Second Year

When grown in containers, pineapple lily (Eucomis sp.) can produce excessively long foliage and tall scapes, particularly in cultivars with tall pineapple lily (Eucomis comosa) parentage. Height control, through the use of plant growth regulators (PGRs), is necessary to improve crop quality of potted pineapple lily. In year 1 of these trials, bulbs of cultivars Reuben, Tugela Jade, and Tugela Gem were given substrate drenches of flurprimidol or paclobutrazol, each at 2, 4, or 6 mg per 6-inch pot. Drenches were applied at the “visible inflorescence” stage. As concentration increased, scapes were generally shorter in all cultivars for both PGRs, but there was no effect on foliage length or production time. At the rates tested, the reduction in scape length was insufficient to produce marketable plants of the three cultivars. In the second year, substrate drenches were applied at an earlier stage than in year 1, at “leaf whorl emergence,” when shoots were about 7 cm tall. The PGR treatments were notably more effective at controlling plant height in the second year. As concentration increased, scape and foliage length was reduced relative to the controls in all three cultivars for both PGRs. For all cultivars, inflorescence leaning and toppling were sharply reduced at all application rates compared with untreated controls. The reduction in plant height observed in year 2, particularly in plants treated with 4 or 6 mg/pot, resulted in plants with compact scapes and foliage proportional with their 6-inch containers.

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Chemical Height Control of Containerized Seashore Mallow

HortTechnology ◽

10.21273/horttech.15.2.0330 ◽

2005 ◽

Vol 15 (2) ◽

pp. 330-332 ◽

Cited By ~ 2

Author(s):

Kimberly R. Hilgers ◽

Cynthia Haynes ◽

William R. Graves

Keyword(s):

Plant Growth ◽

Plant Height ◽

Plant Growth Regulators ◽

Growth Regulators ◽

Kansas City ◽

Chlormequat Chloride ◽

Height Control ◽

Kosteletzkya Virginica ◽

Horticultural Products ◽

Number Of Branches

The objective of this study was to determine the efficacy of plant growth regulators applied as foliar sprays on height and branching of seashore mallow (Kosteletzkya virginica). Five chemical plant growth regulators were applied: ancymidol [15, 25, and 50 mg·L–1 (ppm)] (A-Rest; Elanco Products Co., Indianapolis), dikegulac sodium (500, 1000, and 1500 mg.L–1) (Atrimmec; PBI/Gordon Corp., Kansas City, Mo.), paclobutrazol (10, 20, and 60 mg·L–1) (Bonzi; Uniroyal Chemical Co., Middlebury, Conn.), chlormequat chloride (CCC) (750, 1000, and 1500 mg·L–1) (Cycocel; Olympic Horticultural Products, Mainland, Pa.), and CCC/daminozide mixes (1000/2500, 1000/5000, and 1500/5000 mg·L–1) (Cycocel and B-Nine; Uniroyal Chemical Co.). Ten replicate plants of each concentration were evaluated weekly for plant height and number of branches for 8 weeks. Plants that received CCC and CCC/daminozide treatments at all concentrations and paclobutrazol at 60 mg·L–1 were 60%, 60%, and 48% shorter than control plants and had 113%, 100%, and 75% more branches than control plants, respectively. All concentrations of ancymidol and dikegulac sodium-treated plants were similar to control plants. Paclobutrazol was applied twice, and only the highest concentration was effective for height control. Chlormequat chloride at the lowest concentration was as effective as all other concentrations of CCC and CCC/daminozide.

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

HortScience ◽

10.21273/hortsci.31.4.655d ◽

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.

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

HortTechnology ◽

10.21273/horttech.7.3.269 ◽

1997 ◽

Vol 7 (3) ◽

pp. 269-273 ◽

Cited By ~ 3

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.

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Efficacy of Plant Growth Regulators on the Growth of Vigorous Osteospermum Cultivars

HortTechnology ◽

10.21273/horttech.13.1.0132 ◽

2003 ◽

Vol 13 (1) ◽

pp. 132-135 ◽

Cited By ~ 6

Author(s):

James L. Gibson ◽

Brian E. Whipker

Keyword(s):

Plant Growth ◽

Plant Height ◽

Plant Growth Regulators ◽

Growth Regulators ◽

Growth Regulator ◽

Plant Growth Regulator ◽

Growth Substrate ◽

Height Control ◽

Foliar Sprays ◽

Peduncle Length

Vigorous osteospermum (Osteospermum ecklonis) cultivars Congo and Wildside received foliar sprays of daminozide or daminozide + chlormequat (Expt. 1). Both cultivars responded similarly to the plant growth regulator (PGR) treatments. Only a limited amount of plant height control occurred using 5,000 mg·L-1 (ppm) daminozide + 1,500 mg·L-1 chlormequat or 5,000 mg·L-1 daminozide + 3,000 mg·L-1 chlormequat. Flowering was delayed, phytotoxicity was observed, while peduncle length increased, suggesting that higher concentrations of daminozide or chlormequat may or not be effective at any concentration and may result in increased phytotoxicity. In Expt. 2, `Lusaka' received foliar sprays or substrate drenches of paclobutrazol or uniconazole. Foliar sprays ≤80 mg·L-1 paclobutrazol or ≤24 mg·L-1 uniconazole were ineffective in controlling plant growth. Substrate drenches of paclobutrazol (a.i.) at 8 to 16 mg/pot (28,350 mg = 1.0 oz) produced compact plants, but at a cost of $0.23 and $0.46/pot, respectively, would not be economically feasible for wholesale producers to use. Uniconazole drenches were effective in producing compact `Lusaka' osteospermum plants. Uniconazole drench concentrations of 0.125 to 0.25 mg/pot were recommended for retail growers, while wholesale growers that desire more compact plants should apply a 0.25 to 0.5 mg/pot drench. Applying uniconazole would cost $0.06 for a 0.25 mg drench or $0.12 for a 0.5 mg drench.

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Sclerotium rolfsii Causing Stem Rot of Impatiens walleriana in Brazil

Plant Disease ◽

10.1094/pdis-93-11-1214c ◽

2009 ◽

Vol 93 (11) ◽

pp. 1214-1214

Author(s):

J. M. Soares ◽

F. F. do Crato ◽

D. M. Macedo ◽

R. W. Barreto

Keyword(s):

Fungal Pathogens ◽

Sclerotium Rolfsii ◽

The United States ◽

The Philippines ◽

Stem Rot ◽

Potted Plants ◽

Potted Plant ◽

White Mycelium ◽

Impatiens Walleriana ◽

Garden Plant

Impatiens walleriana, busy lizzy or balsam (local names in Brazil maria-sem-vergonha or beijo-de-frade), is an African member of the Balsaminaceae that has long ago been introduced and established in Brazil. It is now widely cultivated commercially as a potted plant and a popular garden plant (3). It also is a common weed along the coast and is particularly troublesome in some banana plantation areas. There are only two records of fungal pathogens attacking this plant in Brazil: Cercospora fukushiana (leaf spot) and Oidiopsis haplophylli (powdery mildew). In January 2009, a population of diseased plants of I. walleriana was found in a private garden in the city of Rio de Janeiro, Brazil. Plants had rotted and girdled stem bases, leading to a collapse of stems Necrotic areas were covered with fans of white mycelium as well as abundant spherical sclerotia. The fungus was isolated in pure culture by direct aseptic transfer of mycelial fragments and sclerotia to potato dextrose agar (PDA) plates. Colonies were white, cottony, often forming fans, primary hyphae 3.0 to 6.0 μm in diameter, and bearing clamp connections; sclerotia formed after 7 days, initially white becoming dark brown with age, and 0.8 to 1.85 mm in diameter. These are typical features of Sclerotium rolfsii. A specimen was deposited in the local herbarium (Herbarium VIC) under Accession No. VIC 30732. Koch's postulates were performed by inoculating three healthy potted I. walleriana plants (10 × 40 cm high) with approximately 100 freshly collected sclerotia placed in close vicinity with the stem bases. Noninoculated plants kept in a separate pot served as controls. Plants were incubated in a dew chamber for 48 h at 25 ± 2°C. All inoculated plants showed symptoms of stem rot 72 h after inoculation, whereas controls remained healthy. S. rolfsii is a highly polyphagous species that has been recorded to be causing rots (also known as Southern blights) in Brazil on numerous hosts but there are no records of it attacking any members of the Balsaminaceae in Brazil. The only other published records of S. rolfsii on Impatiens spp. are from the United States (Hawaii and Illinois) (2) and the Philippines (1). In South America, there is a single report from Argentina (4) where the disease is regarded as a major threat to the potted plant industry because I. walleriana is one of the most popular potted plants in that country. The potential for losses is also significant for Brazil. To our knowledge, this is the first report of S. rolfsii as a pathogen of I. walleriana in Brazil. Although very damaging to I. walleriana, it is unlikely that this fungus can be used as a natural enemy of this plant species in weed situations because of its wide host range. References: (1) T. O. Dizon and R. B. Pimentel. Philipp. Phytopathol. 29:101, 1993. (2) D. F. Farr and A. Y. Rossman. Fungal Databases, Systematic Mycology and Microbiology Laboratory. Online publication. ARS, USDA, 2009. (3) H. Lorenzi and H. M. Souza. Plantas Ornamentais no Brasil – Arbustivas, Herbáceas e Trepadeiras. Nova Odessa: Instituto Plantarum, 1995. (4). S. M. Wolcan and P. J. Grego. Australas. Plant Dis. Notes 4:54, 2009.

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