FLUORESCENT IN-SITU HYBRIDIZATION AND C-BANDING ANALYSES OF HIGHLY REPETITIVE DNA-SEQUENCES IN THE HETEROCHROMATIN OF RYE (SECALE-MONTANUM GUSS) AND WHEAT INCORPORATING SECALE-MONTANUM CHROMOSOME SEGMENTS

The molecular characterization of C-banded regions of Secale montanum Cuss. by means of in situ hybridization was performed in order to prov ide new information about their chromosome structure relative to culti vated rye, Secale cereale L. Accurate identification of individual chr omosomes was achieved using simultaneous and (or) successive fluoresce nt in situ hybridization (FISH) and C-banding. FISH identification was performed using total rye DNA, three highly repetitive rye DNA sequen ces (pSc119.2, pSc74, and pSc34), and the ribosomal RNA probes pTa71 ( 18S, 5.8S, and 268 rDNA) and pTa794 (5S rDNA). FISH was also used to i dentify the chromosome segment involved in two spontaneous translocati on lines recovered from a 'Chinese Spring'-S. montanum wheat-rye addit ion line. FISH analysis revealed the exact translocation breakpoints a nd allowed the identification of the transferred rye segments. The val ue of this type of analysis is discussed.