Identification of RAPD markers linked to the Ns locus in potato

Using the RAPD method and bulked segregant analysis we identified four RAPD markers Linked to a dominant gene Ns, responsible for a hypersensitive reaction of potato (Solanum tuberosum L.) to potato virus S (PVS) infection. The markers OPE15(550), OPJ13(500), OPG17(450) and OPH19(900) were found to be closely linked to the Ns gene in diploid potato clones. They are situated at 2.6, 3.3, 4.6 and 6.6 cM from Ns, respectively. As a source of the gene, clone G-LKS 678147/60, which is known to carry Ns transferred from S. tuberosum ssp. andigena was used. These RAPD markers were not amplified in resistant tetraploid clones containing Ns derived from the clone MPI 65 118/3, also having an andigenum origin. This suggests that there may be two separate loci of Ns in the sources identified, or different alleles with the same specificity at a single locus, or that the genetic background of tetraploids tested results in different RAPD amplification patterns.