Abstract:

【Objective】 This study was conducted to reveal the relationship between heavy panicle, super-high-yield and physiological properties of indica-japonica inter-subspecific hybrid rice Yongyou 6. 【Method】 A continuing experiment was conducted to evaluate the temperature and light response characteristic, source-translocation-sink characteristic and other physiological properties with the heavy type of indica-japonica inter-subspecific hybrid rice variety Yongyou 6, the light panicle type of conventional late japonica rice variety Xiushui 63, and the middle panicle type of late indica hybrid rice variety, Shanyou 63 during 2003-2008. 【Result】 The results showed that compared to conventional late japonica rice Xiushui 63 (light panicle type, CK1) and late indica hybrid rice Shanyou 63 (middle panicle type, CK2), the heavy panicle type of indica-japonica inter-subspecific bybrid rice Yongyou 6 have many outstanding physiological properties as follows: (1) Strong source that characterized with larger LAI, longer functional period of leaf, higher chlorophyll content of leaf, higher photosynthetic rate of functional leaves, higher specific leaf weight and grain-leaf ratio; (2) Efficient flow that characterized with higher output, output rate and translocation rate of dry matter in single stem and sheath of rice; (3) Greater sink that characterized with increased gross spikelet number, effective spikelet number per unit area, higher yield capacity and heavier single panicle weight (about 5 g); (4) Stronger root system that characterized with developed secondary roots, more roots, higher root activity and higher root/shoot ratio which enhanced the lodging resistance and yield. 【Conclusion】 In order to increase the yield of new indica-japonica inter-subspecific hybrid rice combinations, the breeders have to cooperate with researchers of relevant subjects at the early stage during the parents selection, especially hybrid F1 selection, to evaluate the source-translocation-sink characteristic and root/shoot ratio of parents and new combinations.

Key words: indica-japonica inter-subspecific hybrid rice, heavy panicle type super high yield rice, physiological properties, Yongyou 6