An AFLP-Based Procedure for the Efficient Mapping of Mutations and DNA Probes in Barley

A strategy based upon AFLP markers for high-efficiency mapping of morphological mutations and DNA probes to linkage groups in barley is presented. First, 511 AFLP markers were placed on the linkage map derived from the cross Proctor × Nudinka. Second, loci controlling phenotypic traits were assigned to linkage groups by AFLP analysis, using F2 populations consisting of 30–50 mutant plants derived from crosses of the type “mutant × Proctor” and “mutant × Nudinka.” To map DNA probes, 67 different wild-type barley lines were selected to generate F2 populations by crossing with Proctor and Nudinka. F2 plants that were polymorphic for a given RFLP fragment were classified into genotypic classes. Linkage of the RFLP polymorphism to 1 of the 511 AFLP loci was indicated by cosegregation. The use of the strategy is exemplified by the mapping of the mutation branched-5 to chromosome 2 and of the DNA probes Bkn2 and BM-7 to chromosomes 5 and 1, respectively. Map expansion and marker order in map regions with dense clustering of markers represented a particular problem. A discussion considering the effect of noncanonical recombinant products on these two parameters is provided.