EFFECTS OF FLURPRIMIDOL AND ANCYMIDOL ON GROWTH AND POSTHARVEST PERFORMANCE OF Geogenanthus undatus `INCA'

Abstract

Geogenanthus Ínca' is a new cultivar introduced the foliage plant industry which shows promise in interior plantscaping. The objectives of this study were twofold; to examine the effects of ancymidol and flurprimidol on G. `Inca' growth and determine if plant growth retardant (PGR) application could improve postharvest performance. Four weeks before attaining marketable sizes, the plants were drenched with ancymidol or flurprimidol at 0.0, 0.5, 1.0, or 1.5 mg (a.i.). Plants were then placed in interior-evaluation rooms under 12 μmol·m–2·s–1. Ancymidol or flurprimidol reduced plant height, width, growth index and total leaf area, total dry weight and shoot to root ratio of Geogenathus `Inca'. Flurprimidol increased the deposition of insoluble carbohydrates (starch) and altered the pattern of starch deposition; higher starch content was found in stem tissue compared to foliage tissue. The effects of ancymidol or flurprimidol persisted in the postharvest environment. After 4 months under low irradiance, PGR-treated plants exhibited higher quality, i.e., compact stature and reduced leaf and shoot necrosis. This research has potential significance for the foliage plant industry and it showed that a single drench application at label recommended rates of ancymidol or flurprimidol late in the production cycle can produce desired growth control of Geogenanthus `Inca' in the postharvest environment. Plants retain aesthetic characteristics for extended period thus necessitating lower replacement rate.