Abstract: Physiological traits of super high yielding hybrid rice Xieyou 9308 and high yielding hybrid rice Xieyou 63 were compared. It was observed that Xieyou 9308 has two apical dominance: one is "stem (tiller) growth apical dominance" during vegetative stage, and the other is "inter-grain apical dominance" during grain filling stage. This is the physiological characteristics and basis of high yield of Xieyou 9308. Based on the results, the "physiological model" for Xieyou 9308 is hypothesized. This "physiological model" includes "single stem (tiller) dry matter production superiority basis" with "two apical dominance" as a physiological frame of Xieyou 9308, i.e. (1) high dry matter productivity. Total dry weight of single plant is about 120 g. Plant maintains high productivity after heading, and the dry matter accumulated after heading contributes more than 40% of the total. (2) Stem apical dominance during vegetative stage. The apical dominance is obvious soon after transplanting . The effective tillering finished within two weeks after transplanting. The average panicle-forming rate is more than 65%. (3) Inter-grain apical dominance during grain filling stag. The vigorous spikelets have higher filling potential and reach peak value at two weeks after heading, and the higher filling potential will maintain for a certain period. Filling process of inferior spikelets is laggard, and have an increasing filling potential until maturity as the high transport intensity of the stem and the function leaf senesces slowly at yellow maturity. The yield target of this super hybrid rice model is 11-12 t/hm².

Key words: super hybrid rice, physiological model, apical dominance

摘要： 观察比较了超级杂交稻协优9308和高产杂交稻协优63的生理特性。与高产杂交稻协优63相比，超级杂交稻协优9308表现出两个明显的顶端优势，即营养生长期间的“茎蘖顶端优势”和灌浆成熟期间的“粒间顶端优势”。认为这两优势是协优9308超高产的生理特性和基础，据此提出以单茎（蘖）物质生产优势为基础，以“两个顶端优势”为中心的超级杂交稻协优9308的“生理模型”，即(1) 协优9308 干物质生产能力高，全生育期单株干物质生产量达120 g；抽穗后仍具有较高生产力，此间生物产量占总生物产量的40%。(2) 营养生长期“茎蘖顶端优势”显著，有效分蘖终止期较早，出现在移栽后2周左右，幼穗发育整齐，成穗率>65 %。(3) 灌浆成熟期“粒间顶端优势”显著，优势粒灌浆势高，齐穗后第2周便达到灌浆势的峰值，此后仍保持一定的灌浆能力；劣势粒灌浆进程比优势粒滞后，在临近成熟时，仍未出现灌浆势峰值；支撑劣势粒灌浆势不减的生理机制是：根系衰老迟缓，花后物质运转势较高，功能叶衰老迟缓。这一超级杂交稻“生理模型”的经济产量指标是11~12 t/hm2。

关键词: 超级杂交稻, 生理模型, 顶端优势