籼粳杂交稻甬优2640钵苗机插超高产群体若干特征探讨

选用大穗型籼粳杂交稻甬优2640,以国家粮食丰产科技工程实施基地江苏东海、兴化和海安6.4、6.8和7.3 hm2连片超高产攻关方为依托,对籼粳杂交稻钵苗机插超高产群体(13.5 t hm–2左右)和高产群体(12.0 t hm–2左右)系统比较研究,旨在阐明秸秆还田条件下钵苗机插水稻超高产产量构成及其群体特征。结果表明,与高产群体相比,籼粳杂交稻钵苗机插超高产群体表现穗型大、粒数多和群体颖花量高,有效穗数、结实率和千粒重相当;群体茎蘖数生育前期稳步增长,有效分蘖临界叶龄期达适宜穗数,拔节期高峰苗数量少,拔节之后缓慢消减,最终成穗率高;群体叶面积指数有效分蘖临界叶龄期和拔节期较小,孕穗期达最大值(8.5左右),此后平稳减少,成熟期仍保持3.5以上;群体干物质积累量有效分蘖临界叶龄期和拔节期相当,拔节后积累较快,孕穗期、抽穗期和成熟期显著或极显著增高,且生育中、后期干物质积累比例高;群体氮素积累、群体光合势、群体生长率和净同化率表现为"前小,中高,后强"。说明水稻钵苗机插超高产群体生育中、后期具有较强的光合物质生产力和较高的氮素积累量。本文还探讨了秸秆还田条件下水稻钵苗机插超高产栽培关键技术。

Some Characteristics of Mechanically Transplanted Pot Seedlings in Super High Yielding Population of Indica-japonica Hybrid Rice Yongyou 2640

In order to identify the characteristics of super high yielding population and its yield formation in mechanically transplanted pot seedlings of rice with wheat straw return, we selected a large panicle type indica-japonica hybrid rice Yongyou 2640 as material in Donghai, Xinghua and Hai’an, and analyzed grain yield and its components and characteristics of its super high yielding population (SHY 13.5 t ha^-1) and high yielding population (HY 12.0 t ha^-1). The results showed that, compared with HY, SHY had more total population spikelets owing to its very significantly increased spikelets per panicle. There were no differences in effective panicle, percentage of filled grain and 1000-grain weight between SHY and HY treatments. SHY showed fewer tillers at the early growth stage, achieved expected number of stem and tiller at the critical leaf age for productive tiller, and had lower number of peak tiller at the jointing stage. Then, the number of population stems and tillers began to decrease slowly after jointing. At maturity, the percentage of productive tiller in SHY was higher than that in HY. The leaf area index of SHY was lower than that of HY at the critical leaf age for productive tiller and the jointing stage, the max leaf area index was about 8.5 at booting, which decreased stably after booting, and with the value above 3.5 at maturity. The dry matter accumulation of SHY was comparable to that of HY at the critical leaf age for productive tiller and at the jointing stage, increased greater after jointing, and was higher at booting, heading and maturity than that of HY. The ratio of total biomass accumulation was higher in SHY than in HY at the middle and late growth stage. The nitrogen accumulation, photosynthetic potential, crop growth rate and net assimilation rate were smaller at the early stage and higher at the middle and late stages in SHY. Therefore, SHY has greater photosynthate production and higher nitrogen accumulation than HY at the middle and late growth stage. In this study, we also discussed the key cultivation techniques for super-high-yielding production of pot seedling mechanical transplanting rice with wheat straw return.