Effect of different N-level on plant senesecence and grain yield of rice varieties with different panicle types

Effect of two different levels of soil N-fertilizer on plant growth, leaf senescence and grain yield of erect-panicle and curved-panicle rice varieties were studied under field conditions. The results revealed that diameter in stem base and panicle neck and leaf characters of two rice varieties were better in high-N level than in low-N one. Application of N-fertilizer could inceas chlorophyll content of flag leaf, prolong its relative steady phase (RSP) of chlorophyll content and keep higher leaf area during grain-filling stage. Also there were higher total-N content of flag leaf and longer photosynthetic active duration. Eventually it increased plant dry matter accumulation and grain yield. Under the same N-level, diameter in stem base and panicle neck, activity of flag leaf, grain filling rate, 1000-grain weight, biomass and grain yield were basically better in erect-panicle variety than that in curved one.