| WithⅡyou 498 as material,some physiological characteristics,population development,lodging resistance and grain yield in different transplanting leaf age,planting density and applied high and medium nitrogen.Choose a method which is good for lodging resistance and high yield.1,With the leaf age is growing,the whole growth period is cut short,Root activity is increasing,they are good for cutting down the time of recovering normal growth,the period of achieving highest tiller is cut short,the period of tiller number decreasing is cut down,the period from boot stage to the mature period is prolonged,middle and big seedling is good for slow down senescence in the late period,The high effect LAI indexes and Total LAI indexes with the transplanting stage is growing,the stem,leave,panicle, the total weight of dry materials per unit area in the same stage is decreasing,the pant height is decreasing,the lodging indexes is increasing,the finally growth of superior grain is growing as the transplanting leaf age is growing in middle and high nitrogen treatment. The primary branch number per panicle is decreasing,the effective spike rate,the tiller number per unit area and empty grain is increasing,the plump grain,the theoretical yield is decreasing.2,In the same transplanting leaf age and amounts of applied nitrogen condition,it appears that the speed of changing tiller number is increasing,the rising rate of SPAD in every left position is increasing,the decrease rate of SPAD of each leaf position is slow down,the high efficient leaf area and total leaf area indexes is decreasing,the dry weight of stem,leaf,panicle and the whole dry material in unit area is decreasing,the output and conversion rate of sheath is increasing,the height,the section area,lodging resistance and Bending moment of the corresponding node,the lodging indexes of the first and second node in base are increasing.It appears the same regularity of tiller,the plumpness and the number of thinness grain are increasing,the tiller number per unit area,effective spike rate, the number of effective spike,the primary branch,secondary branch,plump grain,filled grain,shrunken grains,theoretical yield is decreasing.3,In the same transplanting leaf age and plant spacing,the change rate of tiller number,the Attenuation ratio of top three leaves and total ratio of leaves,the decline ratio of LAI after heading were all higher than those of under middle nitrogen;the grain—leaf ratio of top three leaves and total leaves were lower than those of under middle nitrogen, the rise and decrease ratio of SPAD,the dry weight of stem,leaf,spike,total dry material, the ratio that weight of leave compared total dry weight were higher than those of under middle nitrogen,the rate of output and Conversion,the height and the sectional area of compared node,the lodging indexes of the first and second node,the tiller number of unit area,the effective spike number,the primary branch,secondary branch,plumpness, shrunken grains number,empty number,the 1000—grains rate of plump grains,the theoretical yield are increasing.4,After heading 21d,the lodging of stem mostly appears at the first and second internode,the height had a significant positive correlation with lodging resistance;the lodging resistance had a significant positive correlation with thickness of culm,breaking resistance,diameter of stem and dry matter of stem.Breaking resistance had a positive correlation with diameter of stem,thickness of culm and dry weight of unit internode,it also had a significiant negative correlation with height,length of stem,length of internode. The sensitive lodging stage is 21 or 28 days after heading,the internode length,the thickness of stem wall,the stem diameter,the dry weight of unit stem were significantly correlated with 1000-grain weight of plump grain,most of them have achieved significant level,it revels that thickness steam wall is good for formation of big spike,controlling height and cultivation of lodging resistance plant in SRI,steam Plumpness is a key factor for increasing lodging resistance.5,The results suggested that 3 leaf age of seeding,30×30cm population density and nitrogen application rate 225kg/hm~2,which makes the largest yield which is 11.1t/hm~2;5 left and 7 left age of seeding transplanted as the above cultivar method also achieve high yield.
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