Chemical Height Control of Reiger Elatior Begonia1

Abstract

Chemical growth retardants (2-chloroethyl)trimethylammonium chloride (chlormequat), succinic acid-2,2-dimethylhydrazide (SADH, daminozide) and α-cyclopropyl-α-(ρ-methoxyphenyl)-5-pyrimidinemethanol (ancymidol) were tested on Reiger Elatior begonia ‘Schwabenland Red’ (Begonia × hiemalis Fotsch). Chlormequat applied as a spray of 0.30% active ingredient (a.i.) (1:40 dilution of commercial product) caused height retardation in high and low light periods, being most effective in the winter. A 0.30% drench was excessive under low light conditions whereas both 0.30 and 0.60% drenches were ineffective under high light conditions. No significant height retardation was found when SADH was applied as a spray at concentration up to 0.50% a.i. Ancymidol was effective as a drench at 0.125 mg per 15 cm pot under both high and low light conditions. Ancymidol sprays at concentrations up to 33 ppm were ineffective.

Influence of Potting Media, Temperature, and Concentration of Ancymidol on Growth of Chrysanthemum morifolium Ramat.1

“…Ancymidol applied as either a foliar spray or an aqueous drench has provided good height control for many floricultural crops (2,3,5,7,11,12,15,16). Substrate drenches are often the preferred method of application, since they are more pre cise and their effectiveness is less influenced by environmental factors than foliar sprays (14).…”

Growth of Begonia × hiemalis as Influenced by Hand-pinching, Dikegulac, and Chlormequat

“…Cathey and Campbell (5) reported that at lft-c (0.21 |jlE m _2s _1) INC lamps were better for regulating the photoperiod of chry santhemums than high-pressure sodium (HPS) lamps at lft-c (0.15 fiE m _2s _1). The data suggests that HPS lamps are effective for photoperiod control at the illuminance (10 ftc) often recommended (7,8), although the authors did not suggest HPS lamps for that purpose. Low-pressure sodium (LPS) lamps have also been effective for photoperiod con trol of chrysanthemums and have been rec ommended as an alternative to INC lamps because of their high energy efficiency (2).…”

“…Night interruption with incandescent (INC) lamps has been the most recommended method for keeping chrysanthemums vegetative (7,8). Supplemental irradiation of chrysanthe mums from high-intensity discharge (HID) Received for publication Jan. 11, 1982.…”

“…Chlormequat is primarily used to reduce height of poinsettias and to aid in production of early-budded, well-shaped azalea plants (1). Chlormequat sprays effectively have re tarded height of Rieger begonia grown under both high-and low-light regimes (7).…”