To develop near-isogenic lines having each resistance gene to bacterial leaf blight (X. campestris. pv. oryzae), we carried out an inoculation test to select recurrent parents.
　In the inoculation test using seven Japanese races and 13 Philippine ones, three cultivars, IR24, Milyang 23 and Toyonishiki, showed susceptibility to all races. However, two other cultivars, TN1 and IR9101-46, were resistant to some Japanese races.
　Based on this result and past published data given by several researchers, we selected IR24, Milyang 23 and Toyonishiki as recurrent parents to develop near-isogenic lines.
　The purpose of developing near-isogenic lines is to establish a set of international differentials with monogenic base of the resistance to bacterial leaf blight pathogen and to supply reliable materials to breeding programs for resistant varieties.