Effects of Shading on the Senescence of Leaves and Yield of Different Genotype Maize

Studies on effects of shading on senescence of leaves and yield were conducted with different genotype maize by pot tests.The results indicated that,Shading at various stages had different effects on maize leaf area index(LAI).LAI decreased because of seedling and ear shading,but slowed the decreasing of LAI during maize later development due to grain shading.Activities of SOD under shading increased compared with control,In contrast,the content of MDA reduced under shading.Shading also resulted in a severe decline in yield,which was also affected by shading stage.Based on the data the magnitude of shading time in terms of yield reduction was: grain shading ear shading seedling shading.The effects of shading on ear length,bare top length,kernel number per ear and kernel weight per ear were significant at either P=0.05 or P=0.01,and no significant difference caused by shading existed in ear diameter and kernel weight.In addition,Effects of shading on the senescence of maize leaves and yield were obviously different among different genotype maize.