The recessive mutation of the def gene of pea (Pisum sativum L.) leads to the loss of the hilum, the abscission zone between the seed and the pod. Thereby, it reduces the free dispersal of the seeds through pod shattering. As a prerequisite for a gene isolation via a map-based cloning approach, bulked segregant analysis followed by single plant analyses of over 200 homozygous individuals of a population of 476 F2 plants derived from a cross between 'DGV' (def wild-type) and 'PF' (def mutant), were used to detect markers closely linked to the def locus. The AFLP technique in combination with silver staining was used to maximize numbers of reproducible marker loci. Fifteen AFLP loci showed a genetic distance less than 5 and two of them less than 1 centiMorgans (cM) to the gene of interest. AFLPs were converted into sequence tagged sites (STSs) and into a newly refined AFLP-based single locus marker named the 'sequence specified AFLP' (ssAFLP).
