Abstract: To identify changes in agronomic traits associated with yield increase,25 typical japonica rice varieties that were widely planted during the 47 years(1958-2005) were used.The grain yield was linearly increased from 6 198.68 kg/hm2 in 1958 to 12 682.8 kg/hm2 in 2005,with an average annual increase of 137.96 kg/hm2 and an annual increase rate of 2.33% according to the regression equation.Number of spikelets per panicle,grain weight per panicle,seed setting rate and total panicle number increased over released time,which were significantly and positively correlated with yield,with the highest coefficient of correlation(r=0.85**) between number of spikelets per panicle and yield.Moreover,the plant height and stem-leaf angle decreased,but leaf area index at the filling stage increased and heading date postponed over released time.The result indicated that the increase of grain yield was mainly attributed to magnifying of total sink capacity with the increase of number of spikelets per panicle as the key factor.

Key words: japonica rice, genetic improvement, agronomic traits, grain yield

摘要： 对吉林省1958-2005年间育成的25个粳稻品种的产量及农艺性状的研究结果表明,随着粳稻品种的改良，产量呈线性增加。根据回归方程计算，产量由1958年的6 198.68 kg/hm2增加至2005年的12 682.8 kg/hm2，平均每年增加137.96 kg/hm2，增长率为2.23%。每穗粒数、结实率、单穗重和总穗数随育成年代推移显著增加，并与产量呈正相关，其中每穗粒数与产量的相关系数最大（r=0.85**）。株高随育成年代推移显著降低，茎叶夹角显著减小，灌浆期叶面积指数增加，抽穗期推迟。结果表明，产量的增加主要与品种改良过程中总库容的扩大有关,其中每穗粒数的增加是关键。

关键词: 粳稻, 遗传改良, 农艺性状, 产量