Effects Of Total Solar Radiation Decrease And Diffuse Solar Radiation Ratio Increase On The Quality And Yield Of Winter Wheat

Solar radiation reduction with the increase of diffuse radiation fraction has been observed across the middle and lower reaches of Yangtze river in recent half century.Wheat growth and production would be influenced by the changes of solar radiation and its composition.In order to investigate the effects of solar radiation reduction and diffuse radiation increase on the grain filling process of the winter wheat(Triticum aestivum L),two treatments were set in the field experiment,T1(shading rate of total solar radiation shading rate was 14.10%,diffuse radiation fraction was 31.09%)and T2(shading rate of total solar radiation was 14.42%,diffuse radiation fraction was 39.98%),no shading as control(CK).The treatments of experiment were conducted from three leaves stage to mature stage of winter wheat.From 2015-2016 and 2016-2017,the plant height,tiller in winter wheat leaf area index,chlorophyll content and enzyme activity,dry matter weight,yield and related factors,survey the mechanism of solar radiation reduction and diffuse radiation increase effected on yield and quality of winter wheat at each key growth period and every 7d after flowering until maturity.The main conclusions are as follows:1?Solar radiation reduction increased the activity of SOD,POD and CAT,reduced the content of MDA,slowed down the speed of the flag leaf senescence,improved the flag leaf photosynthetic rate,stomatal conductance and chlorophyll content.While the increase of diffuse radiation ratio increased the activity of SOD,POD and CAT,decreased the content of MDA,improved the increase of flag leaf photosynthetic rate,leaf stomatal conductance and chlorophyll content.2?Solar radiation reduction reduced LAI growth rate of winter wheat in pre anthesis and delayed LAI decay rate in post anthesis,improved the dry matter accumulation of dry matter,the largest growth rate and the average rate of winter wheat,decreased total dry matter allocation ratio of grain,reduced the amount of dry matter in pre anthesis and in post anthesis,deereased transloeation,transfer rate and contribution rate rate of dry matter,reduced the grain filling rate and the decrease of per panicle,panicle number,grain weight and harvest index of grains,ultimately reduced the yeild of wheat.While the increase of diffuse radiation ratio improved the LAI growth rate of winter wheat in pre anthesis and delayed LAI decay rate in post anthesis,prolonged dry matter accumulation in fast time,increased the amount of dry matter accumulation of dry matter,the maximum rate of dry matter and average growth rate of dry matter,improved translocation and contribution of dry matter in grains,promoted grain filling rate,the grain number and ear number of 1000 grain weight,ultimately improved the yield.3?Solar radiation reduction decreased the soluble sugar content of leaf and stem,but increased the nitrogen content of grain,the amount of nitrogen accumulation in leaf and stem,improved the protein content,albumin content,globulin content,gliadin content and glutenin content of grains.While the increase of diffuse radiation ratio increased the nitrogen content of the grain,the soluble sugar content of leaf and stem,ultimately improved protein content,grain albumin content,protein content,gliadin content and glutenin content,increasedp the quality of grains.