Efficacy of Paclobutrazol and Gibberellin4+7 on Growth and Flowering of Three Curcuma Species

Abstract

Rhizomes of Curcuma alismatifolia Roxb. `Chiang Mai Pink', C. gracillima Roxb. `Violet', and C. thorelii Roxb. were soaked in gibberellin (GA 4+7 ) at 0, 200, 400, or 600 mg·L -1 (ppm) and planted into 15.2-cm-diameter (6 inches) containers. The plants were grown in a greenhouse at 30 °C day/23 °C night (86.0/73.4 °F) temperatures. When shoot height was 10 cm (3.9 inches), the plants were drenched with 118 mL (3.9 fl oz) of paclobutrazol at 0, 2, 3, or 4 mg a.i. per 15.2-cm-diameter container. Gibberellin 4+7 delayed shoot emergence and fl owering but did not affect the fl ower number. Paclobutrazol rates were not effective in controlling height of C. alismatifolia `Chiang Mai Pink' averaging 85 cm (33.5 inches), C. gracillima `Violet' averaging 25 cm (9.8 inches), or C. thorelii averaging 17 cm (6.7 inches). Curcuma alismatifolia `Chiang Mai Pink', C. gracillima `Violet', and C. thorelii had postproduction longevities of 4.6, 2.6 and 3.8 weeks respectively, making these three species of curcuma excellent candidates for use as fl owering pot plants.