Identification of parents suitable for molecular mapping of immunity and resistance genes in solanum species

A survey of DNA polymorphisms and bacterial ring rot reactions in Solanum species was conducted to identify parents that when crossed would produce an F₁ mapping population useful for identifying DNA markers tightly linked to genes for immunity or resistance to bacterial ring rot. Solanum tuberosum, S. acaule, diploid Solanum species, doubled monoploid lines of S. phureja, and somatic fusion hybrids between S. tuberosum and S. brevidens were established in tissue culture from single true potato seeds or tubers and evaluated for bacterial ring rot reactions in greenhouse studies with root-inoculated tissue cultured plantlets. Establishment of tissue culture stocks insured the availability of homogeneous genetic material for use in bacterial ring rot assays and genetic analyses. Presence of Clavibacter michiganense subsp. sepedonicum was assessed in stems by an immunofluorescence antibody assay (IFAS). Two accessions were found to be immune to bacterial ring rot. DNA polymorphisms were detected within and among 24 accessions evaluated with 24 RFLP markers and 10 arbitrary oligonucleotide primers (RAPDs). These results identify parents suitable for future mapping of gene (s) for immunity or resistance to bacterial ring rot.