Ethephon Foliar Sprays Prevent Premature Flowering of Tissue Culture-propagated Streptocarpus Hybrids

Abstract

<jats:p>Our objective was to quantify foliar ethephon application effects on flowering and growth of several streptocarpus (<jats:italic>Streptocarpus</jats:italic> ×<jats:italic>hybridus</jats:italic>) cultivars. ‘Ladyslippers Blue Halo’, ‘Ladyslippers Deep Blue Vein’, and ‘Ladyslippers Red Rose’ streptocarpus were planted in 6-inch containers filled with a soilless substrate. Foliar spray applications of solutions containing 0, 125, 250, 500, or 1000 mg·L<jats:sup>−1</jats:sup> ethephon were applied either 2 weeks after planting (one application) or 2 and 4 weeks after planting (two applications). After 13 weeks, the total number of inflorescences was recorded and the growth index (GI) and time to flower were calculated. The efficacy of ethephon sprays depended on the concentration, number of applications, and cultivar. A single application of 250 to 1000 mg·L<jats:sup>−1</jats:sup> ethephon delayed flowering of ‘Ladyslipper Deep Blue Vein’ by 9 to 27 days, whereas one application of 1000 mg·L<jats:sup>−1</jats:sup> applied to ‘Ladyslipper Red Rose’ delayed flowering by 9 days. Similarly, two applications of any ethephon concentration delayed flowering of ‘Ladyslipper Deep Blue Vein’ by up to 37 days, while flowering of ‘Ladyslipper Red Rose’ was delayed by 17 days when 1000 mg·L<jats:sup>−1</jats:sup> was applied. The GI of ‘Ladyslipper Deep Blue’ and ‘Ladyslipper Red Rose’ was unaffected by ethephon and, while the GI of ‘Ladyslipper Blue Halo’ was smaller than untreated plants when one or two applications of 500 or 1000 mg·L<jats:sup>−1</jats:sup> ethephon was applied; these smaller plants were still of marketable size and quality. We conclude that ethephon may be used to delay flowering and reduce the number of inflorescences formed before finishing with minimal impact on finished plant size.</jats:p>

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

“…Similarly, cuttings can be treated with ethephon during propagation to further inhibit premature flowering (Runkle, 2013). After transplanting, plants may be treated with ethephon to prevent premature flowering during vegetative growth or the ''bulking up'' phase, or when production times are long (Currey and Flax, 2015). Using ethephon to control flowering is primarily for crops that are already mature and flower readily, such as 6.8 bC 6.9 abBC 7.5 aAB 7.9 aA 200 5.7 cC 6.5 bB 6.7 bAB 7.1 bA C *** T *** C · T * z Within-column means followed by different lower case letters are significantly different by Tukey's honestly significant difference (HSD) test at P # 0.05. y Within-row means followed by different upper case letters are significantly different by Tukey's HSD test at P # 0.05.…”

The Effect of Daily Light Integral, Ethephon, and Node Position of Impatiens ×hybrida Stock Plants on Flowering of the Harvested Unrooted Cuttings

“…Ethephon delays flowering in many species when they are treated with rates of 250-1000 mg•L -1 . For example, two applications of 250 to 1000 mg•L -1 ethephon delays flowering of streptocarpus (Streptocarpus Âhybrida) by 20 to 39 d, respectively (Currey and Flax, 2015). Continuous weekly applications of ethephon can completely inhibit flowering until applications cease.…”