XVI International Botanical Congess

Using microdissected translocated chromosomes for PCR with STS primers derived from genetically mapped RFLP probes, 240 translocation breakpoints were integrated into the seven linkage groups of the Igri x Franka map. A very heterogeneous distribution of recombination rates along individual chromosomes was found. Most recombination is confined to a few distinct subregions which are spaced by large segments of severely suppressed recombination. The regions of highest recombination (<1 Mb/cM) equal to only 5% of the total barley genome but harbour about 50% of the 430 loci of the studied RFLP map. This suggests that such regions among plants of varying genome size are similar in marker-(gene?)-density and recombination, therefore, should be equally accessible to map-based cloning.