Abstract: The varietal differences in opt. leaf area index and opt. number of total spikelets were investigated among rice varieties of various types. From old varieties Da-Che-Jing and Nong-Ken 57 to today's hybrid rice Shah-You 3, the opt. LAI of the three varieties are 3.2, 6.0 and 7.7, respectively. It was shown that the grain yield of a variety increases with increasing of its opt. LAI. The opt.number of total spikelets of Da-Che-Jing and Nong-Ken 57 were 15,630/m² and 28,320/m², respectively. Under good cultural conditions,the spikelet number of semidwarf hybrid rice Gan-Hun 2 may reach 61,000/m² and its grain yield reach 13t/ha. Reducing the number of panicles per unit area properly seems to be a new way to increase the opt. LAI and opt. total spikelet number in the breeding of high-yield rice.

Key words: rice, leaf area index, number of spikelets, population parameter

摘要： 以淮北地区不同历史年代的水稻品种为试验材料,研究叶面积和颖花量与品种产量能力进展的关系。结果指出:随品种最适叶面积指数和适宜总颖花量的增加,水稻品种的产量能力明显提高。因此确认高产品种选育应以增加最适叶面积指数和颖花量并适当减少穗数,应用半矮秆基因为途径。本文根据试验资料提出了目前淮北主要水稻品种的适宜群体指标,为良种选育和高产栽培提供依据。

关键词: 水稻, 叶面积指数, 总颖花数, 群体指标