THE INHERITANCE AND CHROMOSOMAL LOCALIZATION OF AFLP MARKERS IN A NONINBRED POTATO OFFSPRING

AFLP(TM) is a new technique to generate large numbers of molecular mar kers for genetic mapping. The method involves the selective amplificat ion of a limited number of DNA restriction fragments out of complex pl ant genomic DNA digests using PCR. With six primer combinations 264 se gregating AFLP amplification products were identified in a diploid bac kcross population from non-inbred potato parents. The identity of an A FLP marker was specified by the primer combination of the amplificatio n product and its size estimated in bases. The segregating AFLP amplif ication products were mapped by using a mapping population with 217 al ready known RFLP, isozyme and morphological trait loci. In general, th e AFLP markers were randomly distributed over the genome, although a f ew clusters were observed. No indications were found that AFLP markers are present in other parts of the genome than those already covered b y RFLP markers. Locus specificity of AFLP markers was demonstrated bec ause equally sized amplification products segregating from both parent al clones generally mapped to indistinguishable maternal and paternal map positions. Locus specificity of AFLP amplification products will a llow to establish the chromosomal identity of linkage groups in future mapping studies. Since AFLP technology is a multi-locus detection sys tem, it was not possible to identify the AFLP alleles which belong to a single AFLP locus. The consequences of a genetic analysis based on s ingle alleles, rather than on loci with two or more alleles on mapping studies using progenies of non-inbred parents are discussed.