Development of a PCR-based selection assay for root-knot nematode resistance (Rmcl) by a comparative analysis of the solanum bulbocastanum and s. tuberorum genome

A PCR-based assay has been developed for marker assisted selection of root-knot nematode resistance ( Rmc1) in potato. To this end, a comparative genome analysis was carried out between Solanum bulbocastanum and S. tuberosum to identify PCR-based chromosome 11 alleles linked to Rmc1. The use of co-migrating AFLP markers, obtained by using primer combinations previously applied for AFLP analysis of the S. tuberosum genome, failed to align the AFLP map of the S. bulbocastanum genome with the S. tuberosum map. Apparently, the S. bulbocastanum genome is genetically too distantly related to the S. tuberosum genome for this type of analysis. Cleaved amplified polymorphic sequence (CAPS) markers were more readily applied for a comparative analysis within the region of interest. Rmc1 could be localized within a 4 cM interval between markers CT182 and M39b. It is demonstrated that the resistance spectrum of Rmc1 includes not only Meloidogyne chitwoodi and the related species M. fallax but also a genetically distinct population of M. hapla. The cost-efficiency of the CAPS markers applied for Rmc1 renders this approach as an attractive alternative for screening large segregating populations of potato for root-knot nematode resistance