Identifying of pathogen and screening of resistance to bacterial wilt on tomato in Chongqing

Tomato cultivation was set back in Chongqing due to severe incidence of bacterial wilt.Therefore,the work was initiated to identify the pathogen and screen resources with resistance to tomato bacterial wilt.68 isolates of pathogen of tomato bacterial wilt were obtained during 2000-2003. The morphological characteristics,cultural characteristics,biochemical properties and pathogenicity of isolates indicated that they were Ralstonia solanacearum,race 1,and biotype Ⅲ.Studies of methods of seedlings inoculation revealed that injuring and submerging roots of seedlings was the best one,compared with pouring roots and cutting leafs.Ten tomato varieties were evaluated for the resistance to bacterial wilt and the agronomic characters.The results showed that four varieties F9819-2-1,F9802-1-1,600-1-1,and 599-1-1 had high resistance to bacterial wilt,higher yield,good qualities,and are promising breeding materials.