EFFECT OF RHIZOME STORAGE DURATION AND TEMPERATURE ON CARBOHYDRATE CONTENT, RESPIRATION, GROWTH, AND FLOWERING OF ORNAMENTAL GINGER

Abstract

Ornamental gingers are popular cut flowers and more recently have become a promising flowering potted crop because of unique foliage, long-lasting colorful bracts, and few pest problems. The primary means of propagation are by rhizomes in late spring followed by shoot growth and continual flowering. Plants enter dormancy under short days and cool temperatures. Manipulation of rhizome storage to satisfy dormancy requires investigation into the storage environment and duration. Previous studies have indicated that controlling growth, development and flowering in geophytic plants is dependent on reserve accumulation, mobilization, and redistribution. Rhizomes of three ginger species (Curcuma alismatifolia Gagnep., Globba winittii C.H. Wright, and Kaempferia galanga L.) were stored for 0 to 16 weeks at 15, 20 or 25°C to determine the effect on growth, flowering, respiration rates, and carbohydrate content. After treatment application, rhizomes were planted in a soilless medium and placed in a greenhouse with temperatures set at 25°C day/21°C night with 40% shade. Production time, days to emergence (DTE) and days to flower (DTF), were reduced with an increased storage temperature and duration for all species. For Globba and Kaempferia, DTE and DTF were hastened when rhizomes were stored for 16 weeks at 25°C. For C. alismatifolia, DTE and DTF were hastened when rhizomes were stored at 25°C for at least 10 weeks. Respiration and carbohydrate concentration responses were not consistent with rhizome and plant growth responses.