A Study On The Yield Formation And Some Physiology Indexes Under Different Fertilizer Application In Super Hybrid Rice

Field experiments with Super hybrid rice cultivars (LY-293 and ZLY-527) were conducted in Changsha city (28°13' N) in 2004-2005 by using split-plot design with 4 replicates. Three fertilizing treatments, i.e., the low rate (135kgN/hm²+29.7kgP/hm²+112.1kgK/hm²), the middle rate (180kgN/hm²+39.6kgP/hm²+149.4kgK/hm²) and the high rate (225kgN/hm²+49.5kgP/hm² +186.8kgK/hm²) were experimented to study the yield formation and some physiology indexes. The main results were summarized as follows:(1).There were significant differences of the yield and effective panicle number, spikelets number per panicle and grain filling percentage between two years, but not among the fertilizer treatments. The actual yield and spikelet number per panicle in 2005 were higher than those in 2004; but the effective panicle number and grain filling percentage in 2005 was higher than those in 2005. There were no significant differences of yield interaction between the years and the fertilizer treatments. Non significant differences of 1000 grain weigh and harvest index were found between the years and the fertilizer treatments.(2).Super hybrid rice has stronger dry matter production ability, but the process of the dry matter accumulation was different between tested combinations. By making the comparison with ZLY-527, the advantage of dry matter accumulation ability of LY-293 was obvious at early growth stage, but not at middle and late growth stage. The dry matter accumulation is 14.3-14.9t.ha^-1 for LY-293 and 15.0-16.1 t.ha^-1 for ZLY-527. There were significantly positive correlation between the total dry matter production and the grain yield in super hybrid rice, and the correlation coefficient of ZLY-527 and LY-293 isO.9377** and 0.8630**, respectively.(3). The content of NPK above ground plants was the highest at mid-tillering stage in super hybrid rice, and slightly increased as the increase in N fertilizer rate. There were no significant differences among fertilizer treatments. Significant difference of the NPK content above ground plants at different growth stag was found between two years' experiments except for the N content of both LY-293 and ZLY-527 at booting stage.