F_3 lines from Nongtin 20×Dongnong 415 wereused for genetic analysis of blast resistance injaponica rice varieties.One hundred and eigh- teen lines from F_3 were randomly selected and17 seeds from each line were sown in plots.Two plots were set corresponding to two F_3 lines from Nongtin 20 × Dongnong 415 were used for genetic analysis of blast resistance injaponica rice varieties. One hundred and eigh- teen lines from F_3 were randomly selected and17 seeds from each line were sown in plots.Two plots were set corresponding to two