Resistance to Oculimacula yallundae and Oculimacula acuformis is conferred by Pch2 in wheat

The recent report of a differential response of wheat lines containing the Pch2 gene to infection with the eyespot pathogens Oculimacula yallundae and O. acuformis has prompted this re‐examination of the response to these fungi by the recombinant lines used to map Pch2. Homozygous recombinant substitution lines (RSL) derived from the hybridization of Chinese Spring (CS) and the CS chromosome substitution line Cappelle Desprez 7A (CS/CD7A), previously evaluated for response to glucuronidase (GUS)‐transformed O. yallundae, were evaluated for response to infection with GUS‐transformed O. acuformis. Based on visual scores and on GUS expression level, which reflects fungal colonization of seedling plants, evidence of a quantitative trait locus (QTL) conferring resistance to O. acuformis was found in two separate growth chamber experiments (logarithm of the odds, LOD, = 2·7 and 6·7 at 305 and 289 cM, respectively) that was equivalent in location to that for resistance to O. yallundae (LOD = 13·2 and 11·4 at 289 and 304 cM, respectively). These results confirm that Pch2 confers some degree of resistance against both O. yallundae and O. acuformis under these conditions.