Morphological and molecular characterisation confirm that Triticum monococcum s.s. is resistant to wheat leaf rust

The three diploid wheat species Triticum monococcum, Triticum boeoticum and Triticum urartu differ in their reaction to wheat leaf rust, Puccinia triticina. In general, T. monococcum is resistant while T. boeoticum and T. urartu are susceptible. However, upon screening a large collection of diploid wheat accessions, 1% resistant T. boeoticum accessions and 16% susceptible T. monococcum accessions were found. In the present study these atypical accessions were compared with 49 typical T. monococcum. T. boeoticum and T. urartu accessions to gain insight into the host-status of the diploid wheat species for wheat leaf rust. Cluster analysis of morphological data and AFLP fingerprints of the typical accessions clearly discriminated the three diploid species. T. monococcum and T. boeoticum had rather-similar AFLP fingerprints while T. urartu had a very different fingerprint. The clustering of most atypical accessions was not consistent with the species they were assigned to, but intermediate between T. boeoticum and T. monococcum. Only four susceptible T. monococcum accessions were morphologically and moleculary similar to the typical T. monococcum accessions. Results confirmed that T. boeoticum and T. monococcum are closely related but indicate a clear difference in host-status for the wheat leaf rust fungus in these two species.