Foliar Sprays of Flurprimidol, Paclobutrazol, and Uniconazole Suppress Height of Seed-propagated New Guinea Impatiens

Abstract

<jats:p>Our objective was to quantify the efficacy of foliar plant growth retardant applications on plant height and time to flower of seed-propagated new guinea impatiens (<jats:italic>Impatiens hawkeri</jats:italic>) produced in packs and flats. ‘Divine Cherry Red’, ‘Divine Scarlet Bronze Leaf’, and ‘Divine White Blush’ seedlings were planted in 1801-cell packs. Seven days after planting, deionized water (control) or solutions containing ancymidol (15 to 60 mg·L<jats:sup>−1</jats:sup>), chlormequat chloride (750 to 3000 mg·L<jats:sup>−1</jats:sup>), daminozide (1250 to 5000 mg·L<jats:sup>−1</jats:sup>), ethephon (250 to 1000 mg·L<jats:sup>−1</jats:sup>), flurprimidol (10 to 40 mg·L<jats:sup>−1</jats:sup>), paclobutrazol (10 to 40 mg·L<jats:sup>−1</jats:sup>), or uniconazole (5 to 20 mg·L<jats:sup>−1</jats:sup>) were applied to seedlings. A second experiment was performed with the same cultivars quantifying the growth and development in response to a broader range of flurprimidol or paclobutrazol (5 to 40 mg·L<jats:sup>−1</jats:sup>) or uniconazole (2.5 to 20 mg·L<jats:sup>−1</jats:sup>) sprays. Plant height was measured 7 weeks after planting. For Expt. 1, ancymidol, chlormequat chloride, and daminozide had little to no impact on stem elongation. However, flurprimidol, paclobutrazol, and uniconazole suppressed height at flowering of all three cultivars. In Expt. 2, plant height with concentrations flurprimidol, paclobutrazol, or uniconazole up to 27 to 30, 20 to 30, or 4 to 5 mg·L<jats:sup>−1</jats:sup>, respectively, depending on the cultivar. Five to 20 mg·L<jats:sup>−1</jats:sup> flurprimidol or paclobutrazol, or &lt; 2.5 mg·L<jats:sup>−1</jats:sup> uniconazole may be used to control stem elongation of seed-propagated new guinea impatiens for production in flats.</jats:p>

Quantifying Growth Control of Lantana Cultivars Varying in Vigor with Ancymidol, Flurprimidol, Paclobutrazol, and Uniconazole Substrate Drenches

“…Our results on the comparative efficacy of the different active ingredient agree with previous reports (Currey and Erwin, 2012;Currey and Lopez, 2011;Currey et al, 2016). Currey and Erwin (2012) treated 11 different kalanchoe (Kalanchoe) species with a variety of PGRs, including ancymidol, paclobutrazol, and uniconazole.…”

“…Alternatively, paclobutrazol was effective on nine kalanchoe species and uniconazole suppressed stem elongation in every species. Similar variation in the efficacy of PGR active ingredient in controlling growth of new guinea impatiens (Impatiens hawkeri) was reported by Currey et al (2016). Three cultivars of Divine new guinea impatiens were treated with seven PGRs, including ancymidol, flurprimidol, paclobutrazol, and uniconazole.…”

A Study on Plant Height Control of Iris Flowers

“…Soil drenches of uniconazole retarded shoot and petiole elongation of Brassaia actinophylla (Wang et al, 1990). In another study flurprimidol, paclobutrazol and uniconazole suppressed height of 'Divine Cherry Red', 'Divine Scarlet Bronze Leaf' and 'Divine White Blush' Impatiens hawker cultivars (Currey et al, 2016). It was reported that paclobutrazol and uniconazole application reduced plant size and stem length of Kalanchoe 'Rako' (Lee et al, 2003).…”

Quantifying the Effects of Crop-cultural Practices on Growth and Development of Herbaceous Annuals and Perennials in Novel Bioplastic Biocontainers

“…Increasing paclobutrazol concentration led to suppressed growth of angelonia and petunia across biocontainer types, with growth suppression increasing with concentration (Tables 6 and 7). Research has demonstrated that growth inhibition of containerized ornamental plants increases with increasing concentrations of PGRs up to a species-or cultivar-specific concentration, at which suppression is saturated (Barrett, 1982;Currey et al, 2016b;De Hertogh et al, 1976;Whipker et al, 2006).…”

“…Triazoles are the most effective class of PGR labeled for use on flowering ornamental plants; growth control of flowering plants can be achieved when using substrate drench concentrations as low as 0.05 mg•L -1 (Currey and Lopez, 2011). Efficacy of PGR applications can be affected by plant genetics (Currey et al, 2016a), active ingredient (Currey et al, 2016b), application method (Hawkins et al, 2015), and, in the case of substrate drenches, substrate components (Barrett, 1982;Bonaminio and Larson, 1978;Currey et al, 2010). Triazole PGRs are readily absorbed by organic substrate components such as sphagnum peat moss (Barrett, 1982), and the addition of organic substrate amendments affects drench efficacy differently.…”