Submitted to: American Phytopathological Society Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: 5/1/2003
Publication Date: 6/1/2003
Citation: ALI, S., RASMUSSEN, J., FRIESEN, T.L., MERGOUM, M., ELIAS, E. REACTION OF HARD RED SPRING AND DURUM WHEAT BREEDING LINES TO PTR TOXA AND PYRENOPHORA TRITICI-REPENTIS.. AMERICAN PHYTOPATHOLOGICAL SOCIETY ABSTRACTS. 2003. V. 93(6) p. S3. Interpretive Summary:
Technical Abstract: Pyrenophora tritici-repentis is the causal agent of tan spot, a major foliar disease of wheat in the US Great Plains. Ptr ToxA, a host selective toxin produced by races 1 and 2 of the fungus, has been suggested by others as a potential screening tool for developing tan spot resistant germplasm. Between 1998 and 2002, a total of 309 hard red spring (HRS) and durum wheat breeding lines were evaluated for reaction to purified Ptr ToxA and to inoculation with conidia of race 1. Up to 27% of the HRS and 68% of the durum wheat genotypes were susceptible to the fungus but insensitive to Ptr ToxA toxin. These results indicate that reliance on Ptr ToxA as a screening tool may lead to development of toxin-insensitive, disease-susceptible germplasm. Therefore, we conclude that breeding programs should evaluate germplasm with spore inoculations.