In this study,a mutant with super short primary and adventitious roots,less lateral roots and short root hairs was isolated from an EMS (ethyl methane sulfonate)-generated rice mutant library in the Kasalath background,designated as ssr1 (super short root 1).At the 8 d old stage,the length of primary and adventitious roots of ssr1 was only 8.89% and 2.29% of the wild type (WT),respectively.The initiation of adventitious roots of ssr1 was similar as WT,while the initiation and elongation of lateral roots were severely impaired and root hairs were also much shorter than that of WT.Moreover,ssr1 showed dwarf phenotype with plant height less than half of WT.Genetic analysis indicated that the mutant phenotype was controlled by a single recessive nuclear gene.Map-based cloning analysis located SSR1 to a 243 kb region between STS(sequence tagged site)markers 9g7047K and 9g7290K on chromosome 9.The region contains 39 putative genes with none reported to be related to root development of rice.This result will be helpful for the cloning of SSR1 and further characterization of molecular genetic mechanisms underlying root architecture in rice.