Abstract:To investigate the quantitative genetical characteristics of SPAD of flag leaf after flowering at different sites and its correlation analysis with thousand-grain weight (TGW), a 120 recombinant inbred lines (RILs) derived from two Chinese winter wheat cultivars were used. The recipient parent Longjian 19 had strong drought resistance with lower chlorophyll content (SPAD), while the donor Q9086 showed contrasting traits. The results indicated the interaction between water and genotype. There was significantly positive correlation between SPAD of flag leaf and TGW after flowering, while higher correlation (r=0.59^**～0.69^**) was detected between TGW and SPAD of flag leaf (SPAD_g) during filling stage. The SPAD_g showed significantly positive effect on TGW, while that of flag leaf (SPAD_f) during flowering stage was opposite. Gross effect of SPAD to TGW in drought stress was significantly higher than those in normal irrigation condition, and gross effect of SPAD_g to TGW was higher than SPAD_f. Heritability of SPAD of flag leaf and TGW were generally lower (h_B²=0.15～0.44) under different treatments. The number of genes controlling SPAD_f were 22～36 and 50～59, and those controlling SPAD_g were 24～25 and 31～33, while those controlling TGW were 10～11 and 13～14 under drought stress and normal irrigation condition, respectively. The result indicates the feasibility of using this RILs population in genetical study of wheat drought resistance.