关键词: 超级杂交稻；Y两优900；15.0 t/hm2 ；&ldquo, 四良&rdquo, 配套技术

Abstract: New rice yield record was continued to be made under the idea of morphological improvement and heterosis utilization in recent years. The latest breakthrough of yield has been made last year and the new world record is 15.4 t/hm2 in Xupu County, Hunan Province, China. In this paper, the phase IV leading combination YLY900 was used as experimental material, and the control varieties were the phase III typical combination YLY 2 and the classical three-line combination Shanyou 63. The four elite factors in order to reveal the essence of high yield achieved in super hybrid rice were studied. These findings will provide theoretical basis and technical reference for super hybrid rice breeding and super high-yielding cultivation techniques. The main results were summarized as follows：（1）“Elite variety”: YLY900 had higher yield potential of 11.8 t/hm2 in normal ecological conditions, and the yield of YLY900 is 6.3% and 37.2% higher than that of YLY2 and SY63, respectively. The advantages were as follows: YLY900 had good plant type and high photosynthetic efficiency; YLY900 had reasonable tillering dynamics and high percentage of earbearing tiller; YLY900 had photosynthetic physiology advantage in middle and later stages; YLY900 had large panicle with high seed setting rate, which had enough “source”，large “sink” and fluent “flow”. （2） “Elite methods”: The total number of spikelets was up to about 5.0×107 per 667 m2, which guaranteed the grain yield is more than 15.0 t/hm2; Postponing nitrogen application and panicle fertilizer application time were crucial to super high-yielding. （3）“Elite field”: The high soil nutrient content and good air permeability of soil particle composition were the base of super high-yielding. （4） “Elite ecotype”: The excellent climatic ecological condition is a guarantee to obtain super high-yielding. The desirable climatic conditions for super high-yielding cultural techniques were as follows: average daily temperature of canopy during jointing stage to maturation stage is 25℃～28℃; the temperature difference between day and night is more than 10℃; the active accumulated temperature during the whole growth period is more than 3700℃; the sunshine hours is more than 1 200 hours.

Key words: super hybrid rice, Y Liangyou 900, 15.0 t/ hm2, matching technique of “four elite factors”