Wheat-rye chromosome translocations involving small terminal and intercalary rye chromosome segments in the Portuguese wheat landrace Barbela

The old Portuguese wheat landrace aggregate, known as Barbela, shows good productivity under low fertility conditions often associated with acid soils. Using genomic in situ hybridization with rye DNA, we were able to show that Barbela wheat lines contain small, spontaneously occurring, rye chromosome segments representing up to 5 per cent of a chromosome. Two independent accessions were studied which included terminal rye segments, and a further accession had one chromosome pair with a terminal segment and a second pair with an intercalary chromosome segment (3.5 per cent) of rye origin. Small alien chromosome segments are valuable in cereal breeding for transfer of useful characteristics into wheat without deleterious characteristics from the alien. These results show that such translocations may occur spontaneously and be of such high agronomic value that they are selected by farmers as landraces.