Abstract: In order to understand the changes in yield, harvest index (HI) and biomass of aboveground parts of rice, 33 japonica rice cultivars released from 1958 to 2005 were planted. During the 47 years, the grain yield increased from 9 11836 to 15 0601 kg/hm2 and HI from 046 to 055 in the genetic improvement of rice, with the average annual growth rates of 139% and 044%, respectively. In the genetic improvement, the total number of tillers per plant decreased, and the biomass per unit area slightly increased at the harvest stage. The increases of yield and HI resulted from increased biomass of effective tillers and single plant, and the increase of single plant biomass was related to increased biomass of different organs during the genetic improvement. The stem and sheath biomass at heading and the leaf biomass at 30 d after heading showed the biggest increase, up by 7517% and 4994%, respectively. The biomasses of leaves and stem sheath at 10 d after heading, and single plant biomass at 30 d after heading were obviously correlated with the yield. The results indicate that the genetic improvement has resulted in the increase of yield and HI. This increase is correlated with the decrease of total tiller number per plant, and increase of biomasses of effective tillers and single stem. The leaf biomass after heading and the stem and sheath biomass at 10 d after heading can be used as a selection criterion of high yield cultivars.

Key words: rice, genetic improvement, biomass, yield, harvest index

摘要： 以吉林省1958-2005年间育成的33个水稻品种为材料，研究了产量、收获指数及植株地上部分各器官生物量的变化。随着品种的遗传改良，产量、收获指数、有效分蘖生物量和单茎生物量增加，分蘖总数减少。47年间产量由9 11836 kg/hm2增加到15 0601 kg/hm2，收获指数由046增加到055，平均每年分别增加139%和044%。随着品种的演替，单株分蘖总数下降，收获期单位土地面积生物量略有增加。产量和收获指数的增加是有效分蘖生物量和单茎生物量增加的结果。品种改良过程中单茎生物量增加是植株各器官生物量增加的结果，其中，抽穗期茎鞘生物量和抽穗后30 d叶片生物量分别增加7517%和4994%。抽穗后叶片生物量和抽穗后10 d的茎鞘生物量与产量呈显著相关，可作为高产品种的选择指标；抽穗后30 d的单茎生物量与产量呈显著相关。

关键词: 水稻, 遗传改良, 生物量, 产量, 收获指数