Characterization of wheat – Secale africanum introgression lines reveals evolutionary aspects of chromosome 1R in rye

Wild Secale species, Secale africanum Stapf., serve as a valuable source for increasing the diversity of cultivated rye (Secale cereale L.) and provide novel genes for wheat improvement. New wheat - S. africanum chromosome 1R(afr) addition, 1R(afr)(1D) substitution, 1BL.1R(afr)S and 1DS.1R(afr)L translocation, and 1R(afr)L monotelocentric addition lines were identified by chromosome banding and in situ hybridization. Disease resistance screening revealed that chromosome 1R(afr)S carries resistance gene(s) to new stripe rust races. Twenty-nine molecular markers were localized on S. africanum chromosome 1R(afr) by the wheat - S. africanum introgression lines. Twenty markers can also identically amplify other reported wheat - S. cereale chromosome 1R derivative lines, indicating that there is high conservation between the wild and cultivated Secale chromosome 1R. Nine markers displayed polymorphic amplification between S. africanum and S. cereale chromosome 1R(afr) derivatives. The comparison of the nucleotide sequences of these polymorphic markers suggested that gene duplication and sequence divergence may have occurred among Secale species during its evolution and domestication.