AbstractThe aim of this study was to test whether the null alleleEp‐D1cof the endopeptidaseEp‐D1can be used as a marker for theLrl9leaf rust resistance gene. The frequency ofEp‐D1cwas determined in 1134 winter wheat, spring wheat and spelt breeding lines and varieties. Only eight lines were found to carryEp‐D1c.Six of these lines originated from crosses with RL6040, the gene donor for Lrl9. The other two lines were leaf‐rust susceptible in the seedling stage and therefore did not carryLr19.The genetic distance betweenEp‐D1candLr19was determined in a reciprocal cross between the lines FAP75184 (Ep‐D1c, Lr19) and FAP75106 (Ep‐D1a, leaf‐rust susceptible in the seedling stage). Out of 840 F2seedlings screened, 162 were homozygous forEp‐D1c.From 150 of these F2plants, F3seedlings were screened for segregation for leaf‐rust resistance with isolates avirulent onLr19.Only one F2plant produced susceptible F3progeny indicating a recombination event betweenEp‐D1candLr19.From these data, a genetic distance of 0.33 ± 0.33cM betweenEp‐D1candLr19was calculated. The results show thatEp‐D1cis a useful marker for a practical breeding programme allowing the rapid identification