Assignment of the genomic affinities of chromosomes from polyploid Elymus species added to wheat

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Abstract
Genomic DNAs from 10 disomic addition, substitution, or translocation chromosomes from tetraploid Elymus trachycaulus (SSHH) and 13 tetraploid Elymus ciliaris (SSYY) in Chinese Spring wheat were assayed with 18S–28S rDNA (Nor), 5S DNA, Adh, α-amylase, β-glucanase gene clones, and S-genome and H-genome repetitive DNA sequences. The rDNA from the S genome and 5S DNA from the S and H genomes, under high stringency Southern blot analysis, distinguished S-genome and H-genome loci on individual Elymus chromosomes. The single gene, or low copy gene probes (Adh and others), allowed identification of different addition lines and provided information on the gene synteny relationships of Elymus chromosomes with wheat chromosomes. The S-genome specific and H-genome repetitive DNA probes were not useful in assigning genomic affinities, due to some cross-hybridization between these genomes using these probes and (or) the occurrence of large numbers of translocations in polyploid genomes of Elymus species. However, the repetitive DNA probes provided diagnostic phenotypic markers for identification of individual Elymus addition lines. Moreover, since S- and H-genome DNA sequences were virtually absent from wheat, they were excellent markers for the detection of Elymus chromatin in wheat. The array of DNA probes should prove useful in chromosome manipulation in resistance transfer from Elymus into wheat.Key words: Triticeae, Elymus, aneuploid, DNA probe.