Population structure and distribution of Xanthomonas oryzae pv.oryzae physiological races from japonica rice in Northeast China were investigated,and resistance of 30 rice varieties to Race 9 was tested.The results suggested that there were six races in Northeast China,including Race 1,Race 2,Race 3,Race 6,Race 8 and Race 9.The Race 1,Race 2 and Race9 were widely distributed in Jilin,Liaoning and Heilongjiang provinces,while Race3 and Race8 only in Heilongjiang Province,and Race 6 only in Liaoning Province....