Abstract: The population characteristics, such as yield and its  components, accumulation of drymatter and nitrogen of machinetransplanted japonica rice was investigated in three highyield  demonstration fields(over 6.7 hm2 per field) at Zouqu, Caoqiao, and Qianhuang Towns, Wujin County, Jiangsu Province in 2008, and one  highyield demonstration field at Rudong County, Jiangsu Province in 2009. Results showed that yield was closely related with spikelet number per panicle and spikelet number per m2. The spikelet number per m2 should be greater than 45 000  as grain yield  was above 10.5 t/hm2. For highyield mechanically  transplanted rice (above 10.5 t/hm2), the dry matter accumulation from heading stage to maturity paid a contribution rate about 70%~80% to the grain dry weight. Nitrogen accumulation mainly occurred at the two growing stages, before critical tiller leaf age, and after heading. It indicated that higher spikelet number per m2 was the main basic characteristic of high yielding,  mechanically  transplanted japonica rice. And sufficient N supply, improved dry matter accumulation after heading, as well as spikelet number per panicle help increase grain yield of machinetransplanted japonica rice.

Key words: japonica rice, mechanically transplanted rice, population, highyield demonstration field

摘要： 考查了机插常规粳稻超高产群体产量构成、干物质积累以及氮素积累等群体特征。2008年对江苏武进区邹区（品种为武香粳9号）、漕桥和前黄镇（品种均为武运粳7号）等3个百亩连片超高产示范方，2009年对江苏省如东县(品种为宁粳3号)的百亩连片超高产示范方进行了调查。结果表明，机插稻产量与颖花量的相关达极显著，要达到10.5 t/hm2以上的产量，每1m2颖花量需≥ 45 000；籽粒产量10.5 t/hm2以上高产机插水稻的花后干物质积累占籽粒产量的70%～80%；高产机插稻氮素积累的优势在有效分蘖临界叶龄期前和抽穗后两个阶段。足够的颖花量是机插粳稻高产群体的基本特征；保证后期氮素供应、发挥后期干物质积累优势、促进大穗的形成是提高机插水稻产量的主要技术途径。

关键词: 常规粳稻, 机插, 群体, 高产示范方