Effect of Cultivar, Timing, Growth Retardants, Potting Type on Potted Sunflowers Production

Vernieri, Paolo; Incrocci, Giorgio; Tognoni, F.; Serra, G.

doi:10.17660/actahortic.2003.614.47

Cited by 7 publications

(14 citation statements)

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“…1 and 2 had further height restrictions with plants treated at paclobutrazol rates higher than 4.0 mg/pot (Figs. 1 and 4) which was similarly observed in potted sunflower by Barbosa et al (2008), who recommended 6 mg/ pot for 'Golden', and Vernieri et al (2003) with a reported 50% reduction in height at 16 mg/pot (but with variation among cultivars). Dasoju et al (1998) reported severe retardation in the growth of potted sunflower at 16 and 32 mg/pot.…”

Section: Discussionsupporting

confidence: 63%

“…Precedent studies with potted annual sunflower found no differences of flower diameter from control when treated with paclobutrazol substrate drench at 2 or 4 mg/ pot (Whipker and McCall, 2000) or as a foliar spray at 5 to 80 mgÁL -1 . On the other hand, reductions of flower diameter by application of higher paclobutrazol substrate drench rates (4-32 mg/pot) and flurprimidol spray (60 mgÁL -1 ) have been observed Vernieri et al, 2003). The number of flowers and flower buds was totaled for each plant to evaluate PGR treatment Control had no PGR applied.…”

Section: Discussionmentioning

confidence: 99%

“…The most widely used PGR in the United States to control excessive growth in greenhouse-grown floricultural crops is the plant growth retardant paclobutrazol (Rademacher, 2000;Whipker, 2013). Restrictions in height of annual sunflower (Helianthus annuus) in response to paclobutrazol and other PGRs have been demonstrated (Ahmad et al, 2015;Barbosa et al, 2008; 1998; Koutroubas et al, 2014;Vernieri et al, 2003;Whipker and Latimer, 2016;Whipker and McCall, 2000). The rate of paclobutrazol has been evaluated on potted sunflower in previous studies, for example, with Dasoju et al (1998) finding paclobutrazol at 2 mg/pot as a substrate drench on potted sunflower 'Pacino' reduced height by 17% to 25%.…”

mentioning

confidence: 97%

“…Whipker et al (2004) compared two PGRs to flurprimidol and found results from a 2 mg/pot substrate drench application of flurprimidol to be similar to those of paclobutrazol. Another comparison by Vernieri et al (2003) found flurprimidol at 60 mgÁL -1 applied as a foliar spray on sunflower was less effective on height reduction than a low dose of paclobutrazol (2 mg/ pot) applied as a substrate drench. Application of flurprimidol in other species as a drench rather than spray has been shown to produce more ideal plant effects, including reduction in plant size, while not affecting flowering time or flower size (Krug et al, 2005a(Krug et al, , 2005bRezazadeh and Harkess, 2015;Whipker et al, 2006).…”

mentioning

confidence: 99%

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Substrate Drench Applications of Flurprimidol and Paclobutrazol Influence Growth of Swamp Sunflower

Barrios

Ruter

2019

hortte

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ADDITIONAL INDEX WORDS. Asteraceae, chlorophyll meter, flower diameter, growth index, Helianthus simulans, plant growth regulator, plant height, SPAD SUMMARY. Swamp sunflower (Helianthus simulans) is an underused perennial plant native to the southeastern United States that produces an abundance of golden yellow inflorescences in the fall. It is a vigorous grower and tolerates a wide variety of soil conditions, growing in wetland and nonwetland habitats. Swamp sunflower warrants wider use in perennial beds and landscapes, and research on production practices to make plants more suitable for shipping could promote its production. This study evaluated the effects of plant growth regulators (PGRs) on the growth and floral attributes of the swamp sunflower. Treatments were applied to rooted cuttings in 1-gal pots as a substrate drench of 1, 2, 4, or 6 mg/pot paclobutrazol; 0.5, 1, 2, or 4 mg/pot flurprimidol; or water (control)/pot for Expt. 1. A second experiment (Expt. 2) applied 4, 6, or 8 mg/pot paclobutrazol; 2, 4, or 6 mg/pot flurprimidol; or water (control)/pot. Six weeks after treatment (WAT) for Expt. 1, paclobutrazol applied at 4 and 6 mg/pot and flurprimidol at 2 and 4 mg/pot resulted in smaller plants (as reflected by growth index) by 29%, 34%, 22%, and 48%, respectively, compared with the control. Furthermore, at the termination (6 WAT) of Expt. 1, the highest rate of flurprimidol produced the smallest plants, with the exception of the highest rate of paclobutrazol. By 6 WAT, plants treated with the highest rate of paclobutrazol and flurprimidol had lower dry weights and higher chlorophyll measurements than control. All PGR treatments for Expt. 2 resulted in smaller plants than the control by 27% to 36% at 4 WAT and 23% to 41% at 6 WAT. Differences for internode length and flower diameter were observed for Expts. 1 and 2, respectively. Results from these experiments suggest a substrate drench application of 6 mg/pot paclobutrazol or 4 mg/pot flurprimidol can be used for producing smaller plants compared with nontreated plants for swamp sunflower under greenhouse conditions.

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Section: Discussionsupporting

confidence: 63%

Section: Discussionmentioning

confidence: 99%

mentioning

confidence: 97%

mentioning

confidence: 99%

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Substrate Drench Applications of Flurprimidol and Paclobutrazol Influence Growth of Swamp Sunflower

Barrios

Ruter

2019

hortte

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“…Of that total value, annual bedding and garden plants were the most valuable sector, valued at $1.29 billion USD. Controlling growth of containerized annuals is desirable for several reasons, including producing a plant that is proportionately sized for containers (Vernieri et al, 2003), as well as increasing planting densities during greenhouse production (Carey et al, 2007) and on shipping carts for transportation (Fair et al, 2012). Although plant growth and final size are affected by genetics (Currey et al, 2016), environmental conditions and cultural practices including temperature (Erwin and Heins, 1995), irrigation (Alem et al, 2015), and mineral nutrition (Haver and Schuch, 1996) can be manipulated to control growth.…”

mentioning

confidence: 99%

Concentration and Timing of Ethephon Drench Applications Interact to Affect Growth and Flowering of Containerized Angelonia and Geranium

Currey¹,

McCabe²,

Walters³

2016

horts

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Ethephon drenches have been reported to effectively control growth of containerized bedding plants. However, previous researchers have indicated that the effects of ethephon drenches on growth and flowering may differ depending on the timing of applications. Our objectives were to quantify the effects of ethephon concentration, timing of substrate drench application, and their interaction on the growth, size, and flowering of two annual bedding plants. Angelonia (Angelonia angustifolia) and geranium (Pelargonium ×hortorum), seedlings were planted in 10.2-cm-diameter containers filled with a commercial, soilless growing substrate composed of (by vol.) 75% sphagnum peatmoss, and 25% perlite. Five, 10, 15, or 20 days after transplanting seedlings, 70-mL aliquots containing 0, 50, 100, or 200 mg·L−1 ethephon were applied as substrate drenches. Species varied in their growth and flowering responses to ethephon concentration, drench application timing, and their interaction. For angelonia, flowering was delayed most with early applications and high concentrations, and delay was diminished with later applications. Angelonia height was unaffected by late applications, though lateral growth was suppressed 20 days after transplant with 200 mg·L−1 ethephon. Flowering of geranium was only delayed when ethephon was applied 5 days after transplanting, whereas flowering, vegetative height, and shoot dry weight were affected more by earlier applications and higher concentrations. Width and root weight were only affected by ethephon concentration, with growth suppression increasing as concentrations increased. Ethephon is an effective growth regulator when applied as a substrate drench. However, the degree of activity and resulting impact on flowering, size, and growth is influenced by the interaction between ethephon concentrations and the timing of drench applications after transplanting.

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Effects of drought stress on seed germination of ornamental sunflowers

et al. 2017

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Effect of Cultivar, Timing, Growth Retardants, Potting Type on Potted Sunflowers Production

Cited by 7 publications

References 0 publications

Substrate Drench Applications of Flurprimidol and Paclobutrazol Influence Growth of Swamp Sunflower

Substrate Drench Applications of Flurprimidol and Paclobutrazol Influence Growth of Swamp Sunflower

Concentration and Timing of Ethephon Drench Applications Interact to Affect Growth and Flowering of Containerized Angelonia and Geranium

Effects of drought stress on seed germination of ornamental sunflowers

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