Development and application of a genetic map of potato (Solanum tuberosum L.) based on restriction fragment length polymorphisms

A genetic linkage map of potato was constructed based on restriction fragment length polymorphisms (RFLPs) detected by DNA clones from tomato. Potato (Solanum tuberosum L.) and tomato (Lycopersicon esculentum Mill.) are members of the Solanaceae and have the same basic chromosome number (x = 12), but they cannot be cross-hybirdized, and it was not known how conserved the gene order might be between these two species.; The potato map was developed from segregation data derived from the diploid, interspecific cross S. phureja x (S. tuberosum x S. chacoense), and consists of 134 markers defining 12 distinct linkage groups. Nearly all of the tomato probes tested hybridized to potato DNA, and in most cases, the copy number of the employed clones was the same in both species. Furthermore, all clones mapped to the same linkage group in both species. For nine chromosomes, the order of loci appears to be identical in the two species, while for the other three, intrachromosomal rearrangements are apparent, all of which appear to be paracentric inversions.; The RFLP map of potato was applied toward the characterization of genetic variability within and among Solanum species. Twenty seven DNA clones representing one or more sequences on each of the potato chromosomes were used as probes to detect variability among 172 genotypes representing 18 Solanum and two Lycopersicon species. The proportions of restriction fragments shared between all pairs of individuals were analysed to estimate genetic distances. RFLP variability among individuals was sufficient to distinguish all of the accessions, and most of the species. Dendrograms were prepared to represent genetic relationships among the species, and relative genetic diversities within them. The results are discussed in terms of the use of RFLPs as a tool for germplasm evaluation and as an independent source of data to address phylogenetic hypotheses.; Experiments designed to determine the map position of three single genes for disease resistance in potato are described. Data suggest regions of the genome in which some of these genes may be located; and the results are tabulated as a report of progress in an ongoing effort.