Identification and chromosomal organization of two rye genome-specific RAPD products useful as introgression markers in wheat.

Two rye genome-specific random amplified polymorphic DNA (RAPD) markers were identified for detection of rye introgression in wheat. Both markers were amplified in all of the tested materials that contained rye chromatin such as rye, hexaploid triticale, wheat-rye addition lines, and wheat varieties with 1BL.1RS translocation. Two cloned markers, designated pSc10C and pSc20H, were 1012 bp and 1494 bp, respectively. Sequence analysis showed that both pSc10C and pSc20H fragments were related to retrotransposons, ubiquitously distributed in plant genomes. Using fluorescence in situ hybridization (FISH), probe pSc10C was shown to hybridize predominantly to the pericentromeric regions of all rye chromosomes, whereas probe pSc20H was dispersed throughout the rye genome except at telomeric regions and nucleolar organizing regions. The FISH patterns showed that the two markers should be useful to select or track all wheat-rye translocation lines derived from the whole arms of rye chromosomes, as well as to characterize the positions of the translocation breakpoints generated in the proximal and distal regions of rye arms.