THE USE OF RFLPS (RESTRICTION-FRAGMENT-LENGTH-POLYMORPHISMS) DETECTS GERMPLASM INTROGRESSIONS FROM WILD-SPECIES INTO POTATO (SOLANUM-TUBEROSUM SSP TUBEROSUM) BREEDING LINES

The germplasm of the potato (S. tuberosum ssp. tuberosum) has been modified since the beginning of this century by breeders who introgressed important agronomic traits, for example disease resistance genes, from several wild and cultivated Solanum species of the Americas. In this paper we show that the RFLP analysis of potato-breeding material can be used to detect chromosomal regions descended from more-distantly related Solanum species. The RFLP patterns of individuals of ten Solanum species, ten breeding lines of S. tuberosum ssp. tuberosum and the cultivated variety 'Bintje' were analyzed. RFLP data for each of eight single loci of known genomic positions were used for the computation of locus-specific phenograms by distance matrix methods. Several of the potato-breeding lines deviated clearly from the clustered species S. tuberosum, S. stenotomum and S. canasense for one or more of the loci considered. These deviations indicated the presence of "exotic" germplasm at a particular locus. The possibility of detecting such germplasm has implications for mapping the agronomic traits for which the wild species were introgressed and which may still be linked to "foreign" chromosome fragments.