1992－1994年的二年间，对奎冬四号单产500公斤级的群体茎蘖数，叶面积系数，干物质积累等变化进行了实际测定。在栽培上土肥水等基本满足高产田需要的条件下，其结果是，亩基本苗25－28万株。拔节期最高茎蘖数为107－117万，在孕穗期叶面积系数6．2－6．8，灌浆后期单株干物质积累达最大值，收获亩穗数达49．44－51．44万，亩516．8－540．25公斤及相应栽培技术。 In the two years from 1992 to 1994, the change of the number of stems and tillers, the leaf area coefficient and the accumulation of dry matter in the population of Kudingdong IV with a yield of 500kg was measured. Soil fertility in cultivation of water and other basic conditions to meet the needs of high-yield fields, the result is that the basic acres of seedlings 250,000 -280,000. The maximum tillering number at the jointing stage was 10.7-1.17 million and the leaf area coefficient at the booting stage was 6.2-6.8. The dry matter accumulation reached the maximum at the late filling stage, and the harvesting acreage reached 49.44-514.4 thousand , Mu 516.8-540.25 kg and the corresponding cultivation techniques.