*2.5. Rye*

Chromosome pairing analysis of *ph1b* wheat x rye hybrids carrying diagnostic arm-specific C-banding markers showed normal homoeology of the rye chromosome arms lRS, lRL, 2RL, 3RS, 4RS and 5RS to wheat chromosomes. In contrast, 2RS, 3RL, 4RL, 5RL, 6RS, 6RL, 7RS and 7RL paired with wheat chromosomes from a different homoeologous group, denoting they were involved in evolutionary translocations [78,79]. A segmen<sup>t</sup> of 2RS showed some homoeology to 6AS, 6BS and 6DS, a distal segmen<sup>t</sup> of 3RLwas translocated from 6RL, 4RL carries a distal segmen<sup>t</sup> from 6RS and an intercalary segmen<sup>t</sup> from 7RS, a long distal segmen<sup>t</sup> of 5RL was translocated from 4RL, 6RL carries genetic materials from 3RL and 7RL, chromosome arm 7RS carries a translocated segmen<sup>t</sup> from 5RL, and 7RL contains some genetic material from 2RS.

A genetic map of rye constructed with RFLP markers confirmed the implication of six chromosomes in evolutionary rearrangements. Only chromosome 1R preserves the ancestral structure. Six translocations and one inversion were proposed to occur [80]. Later, a high-density linear gene-order map was established from combining a high-throughput transcript map covering 72% of the rye genes with chromosome survey sequencing. Seventeen conserved chromosome segments collinear with barley and wheat genomes were defined, and the sequence of translocations needed to reach this structure was suggested [9].
