ARS | Publication request: DEVELOPMENT OF A RAPD-BASED MAP TO STUDY INTROGRESSION OF RESISTANCE TO COLUMBIA ROOT-KNOT NEMATODE

Submitted to: American Journal of Potato Research
Publication Type: Abstract Only
Publication Acceptance Date: February 15, 1995
Publication Date: N/A

Technical Abstract: A restriction fragment length polymorphism (RFLP) map was developed for a population of seedlings derived from somatic hybrids of wild Solanum bulbocastanum x cultivated potato and succeeding backcross generations. This germplasm is of interest because it exhibits resistance to Columbia root-knot nematode. The RFLP map served to localize the resistance to a single arm of chromosome 11 of the wild donor. Additional markers are being added to the map in the form of Random Amplified Polymorphic DNA (RAPD) markers. There are two objectives for which RAPD's are the logical marker system. Firstly, upon identification of sufficient numbers of RAPD's, these will be used rather than RFLP's for mapping of additional characters. Secondly, during screening of RAPD markers, special attention will be applied to identifying those closely linked to nematode resistance that can be used as selection aids in a breeding program. We are using single 10-mers purchased commercially. To assay for polymorphism, DNA of the wild donor, the cultivated parent of the F1, the recurrent parent, and DNA bulks consisting of nematode resistant and susceptible groupings from BC2 individuals are run with each 10-mer. Presence of unique bands in the wild donor DNA and in bulk BC2, and absence in the cultivated parents DNA are the preliminary tests for selection as candidate informative markers. Individual progeny of the BC2 are screened using candidate markers and mapped in relation to the skeleton RFLP map. All RAPD markers have been located within the RFLP map without difficulty. Ten percent of the 220, 10-mers screened so far have been informative by the criteria of polymorphism and repeatability over replicated PCR runs.