Effects of Water Depth and Temperature on the Seedling Growth of Wild Rice, Zizania palustris L.

Abstract

Under the circumstance of measures for reorganizing paddy field utilization in Japan, the aquatic habit and adaptability to cold climates of wild rice (Z. palustris L.) have stimulated interest in the possibility of commercial cultivation in the northern Japan. To investigate the effects of water depth and temperature on the growth at seedling and early vegetative stages, two experiments were carried out. The glasshouse experiment using Netum showed that seedling growth in terms of dry weight at 30 days after transplanting was accelerated by water depth of 2 cm. In the growth cabinet experiment using K2, increases in dry matter occurred in the range of 2 to 6 cm, being due to increased number and size of leaves and roots. Although plant height was not affected or only marginally affected by water depths, spindly growth with narrow and light color leaves appeared when plants were grown at the depths more than 8 cm. Under the controlled environments, seedling growth was much better in plants grown at 20°C than those at 12°C. There were no interactions between temperatures and water depths, suggesting that temperature is an independent factor of water depth.