Background:The upmost three leaves are generally regarded as the foremost source of photosynthetic products and are associated with yield-related traits in rice.Leaf size such as leaf length and leaf width which inherit quantitatively and greatly affect by growing environment is major determinant of rice leaves,but these traits difficult to measure in large scale on living plant in field.In previous studies,mutants were widely used to study leaf size,but few genes were isolated and cloned.More approaches were needed to try and accelerate the genetic research of leaf shape.