COMPARISON OF COLD TOLERANCE IN SEEDLINGS AMONG JAPONICA RICE VARIETIES

Abstract:

Cold tolerance in seedlings of 5 japonica rice varieties, of which 3 from Japan and 2 (Taizhu 157 and Jianan 20) from Taiwan, and 1 indica rice variety Tesan'ai 2, was studied in Phytotron with light intensity of 1000 and 2000 1x at average temperature of 8.5℃, relative humidity of 75%, and 12 hours of photoperiod per day. Rice seeds were sown in Guangzhou in December 1999. Twenty-day-old seedlings were put into phytotron for 9 days of treatment. The morphological and physiological characteristics, such as plant height，leaf number of main culm，dry weight of shoot， death percentage， chlorophyll content and electrolyte leakage rate were determined ．The results showed that japonica rice Nihonbare，Kinmaze, Fukuhikari and Taizhu 157 had greater tolerance to low temperature than Jianan 20 and indica rice Tesan'ai 2．The japonica rice varieties with cold tolerance will be good donors of cold-tolerant genes for improving indica rice varieties， which will be helpful for preventing the seedlings from cold injury in the early cropping season in Guangdong，China．

Key words:Japonica rice; Cold tolerance; Phytotron; Seedlings