Abstract: Different geno type of rice varieties(Oryza sativa)have been studied on rice rhizo biainter actio ns ino culated with Rhizo bium str ains resulting in the change of root morphology.Microsco pic analysis showed that root hair deformation and curling of rice seedlings star ted from inoculation after 7 days.Most of root hair scurling were about 90皌o 180?,a few root hairs for med 180? to 360癱urling,shorter and thicker lateral root no dular structures for med from inoculation after 35 to 45 days.The frequency of the nodular structure for mation was closely related to the conbination of rice varieties and Rhizo hium strains.