Near‐Isogenic Lines of Wheat Carrying Genes for Stem Rust Resistance

Near‐isogenic lines (NILs) of wheat (Triticum aestivum L.) cartying single genes for resistance to stem rust (Puccinia graminis f. sp. tritici Eriks. & Henn.) are useful in genetical, plant pathological, and physiological studies. A stem rust susceptible, day‐length insensitive genotype was developed for use as a recurrent parent in the production of NILs. Thirty‐eight NILs were produced and tested with nine races of stem rust. Nineteen of the NILs carried numbered Sr (stem rust resistance) genes at identified loci, while 19 carried genes at loci whose relationship to the identified loci was not known. Of the latter group, seven genes appeared to be different from any of the numbered genes. The remaining 12 NILs either were shown to carry numbered genes or still were incompletely tested. Seven of the NILs were resistant to all nine stem rust races, and all but one carried a gene that had been transferred to wheat from a relative.