VISUALIZATION OF SECALE-CEREALE DNA IN WHEAT-GERM PLASM BY FLUORESCENT IN-SITU HYBRIDIZATION

Homozygous wheat/rye (1BL/1RS or 1AS/1RL) translocation lines have sig nificantly contributed to wheat production, and several other wheat/ry e translocation lines show a potential promise against biotic and abio tic stresses. Detecting the presence of rye at the chromosome level is feasible by C-banding and isozyme protocols, but the diagnostic stren gth of genomic in situ hybridization for eventually analyzing smaller DNA introgressions has greater significance. As a first step we have a pplied the genomic in situ hybridization technique to detect rye chrom osomes in a wheat background using germ plasm of agricultural signific ance. By this method rye contributions to the translocations 1BL/1RS, 1AL/1RS, 5AS/5RL and 6BS/6RL could be identified. Differential labelli ng has further enabled the detection of rye and Thinopyrum bessarabicu m chromosomes in a trigeneric hybrid of Triticum aestivum/Th. bessarab icum//Secale cereale.