CYTOLOGICALLY BASED PHYSICAL MAPS OF THE GROUP-2 CHROMOSOMES OF WHEAT

We have constructed cytologically based physical maps (CBPMs), depicti ng the chromosomal distribution of RFLP markers, of the group-2 chromo somes of common wheat (Triticum aestivum L. em Thell). Twenty-one homo zygous deletion lines for 2A, 2B, and 2D were used to allocate RFLP lo ci to 19 deletion-interval regions. A consensus CBPM was colinearily a ligned with a consensus genetic map of group-2 chromosomes. The compar ison revealed greater frequency of recombination in the distal regions . Several molecularly tagged chromosome regions were identified which may be within the resolving power of pulsed-field gel electrophoresis. The CBPMs show that the available probes completely mark the group-2 chromosomes, and landmark loci for sub-arm regions were identified for targeted-mapping.