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

Abstract

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 thaof 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.