Abstract:

The growth, photosynthetic characteristics and grain yield were studied using paddy rice “Shanyou 63” and upland rice “Zhonghan No 3” with five treatments: A (irrigated water was 25% of CK), B (irrigated water was 43.75% of CK), C (irrigated water was 62.5% of CK), D (irrigated water was 81.25% of CK) and E (irrigated watered 12 000 m³/hm², CK). The results showed that irrigation treatments affected obviously the characters above in two kinds of rice. Compared with those under conventional irrigation, the loss of grain yield of Zhonghan No 3 was 68.42% and the difference was significant in treatment A, while not significant among other treatments. The losses of grain yield of Shanyou 63 in treatment A and B were 80.58% and 42.98%, respectively, while the difference of grain yield was not significant among treatment C, D and E. In our research, the optimal irrigated water was 7 500 m³ per hm² and 5 250 m³ per hm² to produce high yields for Shanyou 63 and Zhonghan 3, respectively. When irrigated water was beyond the values, grain yield of the two cultivars decreased. Upland rice save about 30% of irrigated water than paddy rice to produce high yield. In all of water treatments, the yields of upland rice were lower than that of paddy rice because of less effective panicles per plant in Zhonghan 3.

Key words: Irrigated water, Photosynthetic characteristics, Grain yield, Paddy rice, Upland rice