To investigate the morphological and physiological characteristics relating to root lodging tolerance in direct-seeded rice plant, anchoring ability, root growth and its distribution to soil layers were compared among root lodging-susceptible Japanese varieties, tolerant USA varieties and Korean semi-dwarf indica varieties. Pushing resistance, i. e. the maximum resistance of plant to horizontal pushing and inclination of shoot to 45? toward the verical direction, was higher in tolerant USA varieties and Korean semi-dwarf indica varieties than in susceptible Japanese varieties. Tolerant varieties developed a larger amount of roots at full heading stage than susceptible Japanese varieties, due to the higher rate of dry matter allocated to roots in USA varieties and higher crop growth rate in Korean semi-dwarf indica varieties. Also, tolerant varieties developed a larger amount of roots in deeper soil layers than susceptible varieties. The pushing resistance was remarkably reduced when root elongation to the subsoil layers was prevented by laying an unwoven cloth between the topsoil and subsoil layers. The higher soil strength and bulk density in the subsoil layers was attributed to the higher efficiency of a unit root weight in the subsoil layers for anchoring compared with that in the topsoil layers. The above results indicate that root growth, especially root development in the subsoil layers, contributes significantly to the anchoring ability and lodging tolerance in direct- seeded rice plant.