INFLUENCE OF PHOTOPERIOD AND GIBBERELLIC ACID ON GROWTH AND FLOWERING OF CRASPEDIA UNIFLORA.

in HortScience
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  • 1 Department of Plant and Soil Science, Southern Illinois University, Carbondale, IL 62901.

Flowers of Craspedi a uniflora (Billy Buttons), a New Zealand annual plant, have been introduced recently into the U.S.A. florist market. Craspedia is relatively unknown in the U.S.A., but is beginning to be utilized by florists as a cut flower and has potential for specialty cut flower production. Craspedia uniflora cut flowers were grown from seed in an inflated, double-layer, polyethylene greenhouse. Short day (SD) and long day (LD) photoperiod treatments were applied by daylength reduction via black cloth and night interruption lighting, respectively. Treatments began 10 weeks after sowing (15 leaf stage) and continued until harvest. Gibberellic acid was applied as a single foliar spray to runoff at 0 and 500 mg·liter-1 at initiation of photoperiod treatment. Long day treatment reduced days to anthesis, increased flower number, and decreased stem length and plant fresh weight. Gibberellic acid (500 mg·liter-1) increased foliage height under both photo period treatments and increased plant dry weight under LD but reduced dry weight under SD treatment. Flower fresh weight, diameter and bud number were not affected by treatment.