Abstract: To search the differences of biomass and nitrogen accumulation and distribution in different organs of new and old hybrids. Field experiment was conducted in which commercial maize hybrids ZD2 at 1970s and two commercial maize hybrids XY335 and ZD958 at 2000s, their N fertilization were 100,200 kg/ha, and the plant density were 52 500, 75 000,105 000 plants/ha, respectively, to definite the difference of nitrogen nutrition strategy and adjustment mechanism. The results showed that quality of new varieties biomass in pro-silking were higher than old varieties by 0.43 t/ha, the stem/leaf dry matter(2.53) and the stem/leaf nitrogen accumulation at silking(0.76) of new varieties were significant lower than old varieties in silking separately by 11.7% and 15.8%, the leaf removable nitrogen/grain nitrogen at maturity of new varieties was higher than old variaties by 4.3%. In two years, an average of new varieties was 6.21% leaves biomass and 24.7% stem biomass in pro-silking for external transport from R1 to R6, and the average of old varieties was 12.7% leaves dry matter and 29.1% stem biomass. Under different cultivation conditions, the ration of leaf N translation and leaf N accumulation in silking always kept 63%, and the stem was 60%. In other words, the biomass and N accumulation strategy in pro-silking of new varieties were more focus on leaves, but the old varieties were more foucs on stem, the new varieties precedent activate stem nutrient transport in post-silking stage, to provide a buffer for leaf nutrient transport prematurely, and ensure the function of leaves in post-silking stage to obtain higher yield. In the course of variety replacement, the N transport extremity of leaves and stems were similar in new and old varieties, the new varieties had higher N accumulation and translation strategy, to have more higher yield in different cultivation conditions.

Key words: Maize, Dry matter, Nitrogen, Accumulation and transport

CLC Number: 

• S143.1