Development of oligonucleotide probes for FISH karyotyping in Haynaldia villosa, a wild relative of common wheat

Haynaldia villosa is a wild relative of wheat and a valuable gene resource for wheat improvement. Owing to the limited number of probes available for fluorescence in situ hybridization (FISH), the resolution at which the karyotype of H. villosa can be characterized is poor, hampering accurate characterization of small segmental alien introgressions. We designed ten oligonucleotide probes using tandem repeats in DNA sequences derived from the short arm of H. villosa chromosome 6V (6VS). FISH with seven of them resulted in clear signals on H. villosa chromosomes. Using these, we constructed FISH karyotypes for H. villosa using oligo-6VS-1 and oligo-6VS-35 oligonucleotides and characterized the distribution of the two probes in five different H. villosa accessions. The new FISH probes can efficiently characterize H. villosa introgressions into wheat.