中文摘要：

在群体水培条件下，以国内、外不同年代育成的常规籼稻代表品种（2001年88个、2002年122个）为材料，测定生育期、株高、干物重（包括根系）、产量及其构成因素、穗部性状、氮素、根系性状等，采用组内最小平方和的动态聚类方法将供试品种按单穗重从低到高依次分为A、B、C、D、E、F6类，研究各类品种产量形成的差异及其原因。结果表明：①大穗型水稻品种生育期较长，植株较高；②大穗型品种最高茎蘖数少，成穗率低，单位面积穗数少，每穗粒数多，千粒重大；③大穗型品种穗长较长，一、二次枝梗数多，着粒密度大。在适当增加穗长的基础上，增加二次枝梗数的比例，提高着粒密度是提高籼稻品种单穗重的主要途径；④单穗重与个体（单穗）产量呈极显著线性正相关，与群体产量呈极显著的抛物线型关系。选用穗粒数较多、千粒重较大且有足够穗数的偏大穗型品种较易获得高产与稳产的目标；⑤生育期较长、植株较高、穗重大是大穗型品种高产的基础，根系发达，氮素积累多，叶面积系数较大，光合能力强，是大穗型品种高产的主要原因。

英文摘要：

To investigate the difference and its cause of yield formation in conventional indica rice （Oryza satiua L） cultivars with different panicle weight （PW）, a total of 88 and 122 conventional indica rice cultivars were solution-cultured in 2001 and 2002, respectively. Based on PW, these cultivars were classified into 6 types in the alignment from low to high. Growth duration, plant height, dry matter weight （ineluding root）, yield and its components, panicle traits, nitrogen content of each plant part and root traits were investigated. Results were as follows： ① For rice cultivars with large PW, growth duration was longer and plant height was higher than those of other rice types. ② Rice cultivars with large PW showed the lower maximum tiller number, the percentage of productive tillers and panicles number per unit area, and higher spikelets per ear and 1000-grain-weight than other rice types. ③ Rice cultivars with large PW also showed the longer panicle length, higher spikelet density and higher number of primary and secondary branches on the panicles than other rice types, which indicated that on the base of properly increasing of panicle length, the single panicle weight could be elevated through increasing the percentage of secondary branches and improving grain density per panicle. ④ Panicle weight showed a quadratic parabola relation with population grain yield and a significant positive linear relationship with grain yield per panicle, which showed that to reach high and stable yield target, those cultivars with moderately larger panicle, higher spikelets per ear and 1000-grain-weight should be considered in the selection and breeding of conventional indica rice. The longer growth duration, higher plant height and larger panicle weight were the base for high grain yield and the developed root system, more accumulation of nitrogen, larger leaf area index and greater photosynthetic capacity were the main causes of high grain yield in rice cultivars with large PW.