Hagiladi, A., Dept of Ornamental Horticulture, ARO, Volcani Center, P.O. Box 6, Bet Dagan 50250, Israel
Umiel, N., Dept of Ornamental Horticulture, ARO, Volcani Center, P.O. Box 6, Bet Dagan 50250, Israel
Yang, X.-H., Dept. of Ornamental Horticulture, Institute of Vegetables and Flowers, Chinese Academy of Agri. Sciences, 30 Bai Shiqiao Road, Beijing 100081, China

Curcuma alismatifolia is a new cut flower crop with potential for expansion in the markets. As a tropical geophytic plant, its cultivation requires heated greenhouses since short daylength and low temperature are the two limiting environmental factors for growth and development of this plant during the winter in Israel. The present study explored the possibility of extending Curcuma flower production from autumn into winter, at minimal heating expense. In our experiment, all the plants were first grown for 11 weeks in the phytotron, under 29/21°C (day/night) and natural daylength (11 to 12 h). Then plants bearing 5 leaves were allocated to 4 groups and transferred to grow under a factorial combination of day/night temperatures - (23/15 - LT and 26/18°C - HT) and daylength (lOh sunlight - SD and lOh sunlight + lOh supplemental incandescent light -LD). Compared with LT, HT enhanced growth of both above- and under-ground parts. Yields of inflorescences and propagules were higher under LD than under SD, whereas we did not find significant differences in the results between HT and LT under LD. Under SD, HT reduced the yield of inflorescences per plant (0.5) when compared to LT (0.7). The scape was thicker under LD and LT than under SD and HT, respectively. Under LD, warmer conditions increased the scape length when compared to cooler conditions. The number of storage roots (t-roots) per propagule was higher under SD than under LD conditions, as well as in HT versus LT under SD. In the propagule, connecting roots which connect the t-roots to the rhizome were longer under LD than under SD conditions.