Abstract: A non-T-DNA insertion spotted leaf mutant W1764 was identified in a transgenic offspring of rice(Oryza sativa L.)indica cv.Minghui86.The spot phenotype was first appearing at the tip part of the lowest leaf at late stage of tillering.As the plant growing,the spot spread from tip part to the whole leaves from lower leaves to the upper ones.When the mutant plant matured,the spot spread to the whole plant.Genetic analysis showed that the mutant phenotype was controlled by a single recessive gene.F2 population build up with mutant W1764 and hybrid rice varieties 02428,and the 136 mutant phenotypes were used for gene targeting,we mapped the mutant gene in 1.9 cM interval between DNA marker NSSR1229 and L05-78 on the long arm of chromosome 12.We temporarily named the gene as spotted leaf 30(t)spl30(t).