Introgression of rye chromatin on chromosome 2D in the Portuguese wheat landrace 'Barbela.'.

The old Portuguese wheat landrace aggregate known as 'Barbela' shows good productivity under the low-fertility conditions often associated with acid soils. The use of genomic rye DNA, in combination with 45S rDNA and the repetitive sequences dpTal and pScl 19.2 as probes, in two sequential in situ hybridization steps enabled the identification of all chromosomes in the 'Barbela' wheat lines and the detection of the introgression of rye-origin chromatin onto wheat chromosome arm 2DL in two of the lines. Amplification of microsatellite loci using published primer pairs showed that the distal segment of wheat chromosome 2DL, which was involved in the rye translocation, was deleted. The identification and characterization of small recombinant chromosome segments in wheat-rye lines may allow their use in plant breeding programmes. Their presence in farmer-maintained material demonstrates the importance of maintaining, characterizing, and collecting landrace material before valuable genetic combinations are lost as uniform commercial crops are introduced.