Effect Of Nitrogen Topdressing Stage On Grain Yields And Qualities Of Wheat Following Rice

The test had been completed in Guiji village, Fengtai County of Anhui Province, from 2006 to 2008. According different nitrogen topdressing stage, selecting Yannong19, Wanmai52, and Wanmai48, studying the effect of different nitrogen topdressing stage on growth and development, yield and formation factors and main quality traits of different varieties. The main findings are as follows:1 the effect of different topdressing stage on growth and development and a number of physiological characteristics of different varietiesFor different topdressing stage, the tendency of varieties groups number of stems and tillers is increased first and reduced later, along with the rearward shift of topdressing stage, and three varieties reach the maximum when topdressing at the jointing stage. For leaf indicators of soluble sugar, the tendencies of soluble sugar, from the three varieties of wheat leaf, are increasing constantly, along with the rearward shift of topdressing stage, and reach the maximum when topdressing at the booting stage, Yannong19 up to 3.05%, Wanmai52 up to 3.12% and Wanmai48 up to 3.11%. About the soluble sugar of grains, three varieties reach the maximum at the seventh day after flowering. And Yannong19 is the highest, followed by Wanmai52 and Wanmai48, three varieties maintain the highest soluble sugar when topdressing at the jointing stage. About grain filling rate, three varieties of wheat maintain the highest 1000-grain weight when topdressing at the jointing stage. In the photosynthetic rate, three varieties of wheat reach the maximum at 10:00, and they have the largest numerical differences.2 the effect of different topdressing stage on production and constituent elements of different varietiesIn the different treatments of three varieties, topdressing at jointing stage, the ears number reaches the maximum, the ears number of Wanmai48 is the highest in the three species. In the kernel number, three varieties of wheat are increased first and decreased later, along with the rearward shift of topdressing stage, and reach the maximum at the jointing stage. Among of them, Yannong19 is the highest, 39.36 per ears. About 1000-grain weight, topdressing at the jointing stage, Yannong19 and Wanmai48 reach the maximum, but Wanmai52 reach the largest at the boot stage. About bulk density, three varieties are increased first and decreased later, along with the rearward shift of topdressing stage, and topdressing at the jointing stage, they are the largest. The production of Wanmai48 is the largest, reached 554.66kg/667m2, need topdressing at the jointing stage, followed by Yannong19 is 530.9kg/667m2, and Wanmai52 is 522.96kg/667m2.The yield and structure factor positive correlation of Yannong19, with grain number per spike and bulk density difference reached very significantly and significantly(r=0.97**,r=0.91*);The yield and structure factor positive correlation of Wanmai52, with spike number and grain number per spike difference reached significantly(r=0.91*,r=0.94*);The yield and structure factor positive correlation of Wanmai48, with 1000-grain weight and bulk density difference reached very significantly and significantly(r=0.99**,r=0.88*)。3 the effect of different topdressing staget on quality traits of different speciesThe wet gluten content,SDS sedimentation values,the swelling power and alkaline water retention capacity could be improved by the rearward shift of topdressing stage.All reaches the maximum at the boot stage. the wet gluten content of Yannong19 higher than Wanmai52 and Wanmai48. The highest of wet gluten content of Yannong19,Wanmai52 and Wanmai48 is 41.53%,37% and 33.33%. The highest SDS sedimentation values of Yannong19 higher than Wanmai52 and Wanmai48 too . The highest the swelling power of Wanmai52 higher than Yannong19 and Wanmai48.In the properties of starch pasting, the peak viscosity of Yannong19 reaches the largest when topdressing at the booting stage, but Wanmai52 and Wanmai48 have the highest peak viscosity when topdressing at jointing stage. Low viscosity of the three varieties is reduced first and increased later, and reach the maximum when topdressing at the booting stage. Dilute value of the three species reaches the maximum when topdressing at the booting stage. The final viscosity, rebound values and gelatinization time of three varieties, achieve the highest when topdressing at the booting stage, oppositely gelatinization temperature is the lowest, so the quality of wheat could be improved by the rearward shift of topdressing stage.