Growth and development characteristics of super-high-yielding mid-season Japonica rice

Chinese. 水稻是中国最重要的粮食作物，实现水稻超高产对保证国家粮食安全有重要作用。本研究旨在探讨超高产水稻（产量11 ton/ha）的生长发育特性。4个中熟粳稻品种（含品系）连嘉粳2号、华粳5号、0026和9823种植于大田，对其物质生产和产量形成进行了观察分析。与高产水稻（CK，产量为8.98～9.16 ton/ha）相比，超高产水稻每穗颖花数多，结实率高，千粒重与CK无显著差异；超高产水稻移栽至拔节期的茎蘖数较CK少，但分蘖成穗率较高；超高产水稻的叶面积指数、光合势和干物质积累，生育前期较CK低，抽穗期与CK无显著差异，抽穗后则显著高于CK。超高产水稻各生育时期的根冠比、抽穗至成熟的根系伤流量以及粒叶比、茎鞘物质运转率和收获指数均显著高于CK。提出了中熟粳稻超高产群体的生育诊断指标：总颖花量4.5万/m2，结实率90%，千粒重26 g；茎蘖成穗率80%，抽穗期叶面积指数7.5～8.0，全生育期光合势5×10. m. /d/ha，成熟期总干重22 ton/ha，收获指数0.51；抽穗期粒叶比[颖花/叶(cm. )]0.58，根冠比0.25，根系伤流量5 g/m. 2/h。对培育超高产水稻群体的调控途径与关键栽培技术进行了讨论。

English. Rice is one of the most important food crops in China. The realization of its super-high-yielding has a great significance for food security of the country. This study investigated the growth and development characteristics of the super-high-yielding (grain yield 11 ton/ha) of rice. Four mid-season japonica rice cultivars (including lines), Lianjiajing 2, Huajing 5, 0026 and 9823, were grown in a paddy field. Growth analysis was performed during the growth period, and yield and yield components were determined at maturity. Super-high-yielding rice had more sipkelets per panicle and higher filled-grain percentage than the high-yielding rice (CK, grain yield 8.98～9.16 t/ha). There was no significant difference in 1000-grain weight between the super-high-yielding and the CK. Super-high-yield rice exhibited fewer tillers at the early growth stage (from transplanting to jointing), while a higher ratio of productive tillers to total tillers, as compared with the CK. The leaf area index, photosynthetic potential and dry matter accumulation of the super-high-yielding rice were lower than those of the CK at the early growth stage, and their differences were not significant between the two rice types at heading, and were greater for the former than the later after heading. The root-shoot ratio at each growth stage, root bleedings from heading to maturity, grain-leaf ratio, translocation percentage of the matter from stems and sheaths and harvest index of super-high-yielding rice were greater than those of CK. The indexes for the growth and development of super-high-yielding mid-season rice population were suggested, i. e., total spikelets 4.5 × 10. /m. , filled-grain percentage 90%, 1000-grain weight 26 g; ratio of productive tillers 80%, leaf area index at heading 7.5-8.0, photosynthetic potential during whole growth period 5×10. m. /d/ha, total dry matter weight at maturity 22 ton/ha, harvest index 0.51; grain-leaf ratio (No of spikelets per cm2 leaf area) 0.58; root-shoot ratio at heading stage 0.25 and the amount of root exudates 5 g/m. /h. The regulation approaches and key cultivation techniques for raising the super-high-yielding population were discussed.