Effect of Low Light at Different Grain Filling Stages on Dry Matter Accumulation and Yield of Waxy and Non-waxy Wheat

In field conditions,waxy wheat variety Nongdanuo 50222 and non-waxy wheat cultivar Lunxuan 987 were used to study the effects of low light intensity at different grain filling stages on dry matter accumulation and yield.The photosynthetic active radiation was cut 60% by shading with black plastic net,and the natural condition was taken as the control.The results showed that biological yield and grain yield of Luxuan 987 decreased significantly after shading during middle and later grain filling stages,while those of Nongdanuo 50222 showed the similar trends after shading during early and middle grain filling stages.The translocation of dry matter,which produced in vegetative organs before flower,from vegetative organ to grain and its contribution rate were greatly affected by shading after anthesis,and the effect varied with wheat genotypes.The dry matter translocation of Luxuan 987 from vegetative organ to grain was decreased significantly after shading during early grain filling stage,but increased markedly after shading at later grain filling stage,which were the same asthe contribution rate of dry matter translocation to grain.As to Nongdanuo 50222,shading after anthesis improved the translocation of dry matter from vegetative organ to grain,the highest translocation amount was observed for shading during middle grain filling period.With the delay of shading time,the contribution rate of translocation dry matter to grain increased and then decreased in Nongdanuo 50222,and the contribution rate of later shading treatment was below the control,other treatments were higher than the control.The grain-filling processes of wheat were changed by low light intensity.With delay of shading time,the fast-increase period and slow-increase period of Luxuan 987 were shortened.The grain-filling process of Nongdanuo 50222 was significantly affected by shading during middle grain filling stage,which extended the fast-increase period.The grain yield and economic index of waxy and non-waxy wheat were declined significantly by shading during middle grain filling stage.