Detection of rye DNA in wheat-rye hybrids and wheat translocation stocks using total genomic DNA as a probe

Total DNA was extracted formSecale cereale L. cv. ‘Petkus’ and labeled with biotin-11-dUPT. Labeled rye DNA and non-labeled wheat DNA in a mixture of 1∶1 were used as a probe on chromosome preparations of Welsh triticale and Kavkaz wheat, a wheat translocation stock. Hybridization of denatured probe and chromosomes took place overnight at 37°C in the presence of 10% (w/v) dextran sulfate, 50% (v/v) formamide, 10 mM PIPES, 0.1 mMEDTA and 0.3 M NaC1. Biotin-labeled rye DNA was detected using streptavidin-horseradish peroxidase conjugate. Staining was made with diaminobenzidine tetrahydrochloride and hydrogen peroxide. Observations made on Giesma counter-stained slides indicated that the rye chromosomes in Welsh triticale and the two short arms of a pair of satellite chromosomes (1RS) in Kavkaz wheat were preferentially labeled. Hybridization signals were seen as dark brown to bluish black in color. The technique described above is simple. It does not require the isolation of a species-specific probe. Itallows rapid identification of hybrids and/or chromosome translocations in wide hybridizations.