Infection type data were used to postulate the presence of stripe rust seedling resistance genes in 20 CIMMYT and related bread wheats. Yr3, Yr6, Yr7, and Yr9 were hypothesized to be present in 12 lines, either alone or in combination. The isolates used also indicated the presence of additional unknown seedling resistance genes. Four lines produced only low seedling infection types. Four other lines displayed adult plant resistance.
