Potato (Solanum tuberosum L.) breeding for PVY resistance is of utmost importance, in view of the great damage this disease can cause. The establishment of triplex (RyRyRyry) or quadruplex (RyRyRyRy) clones as parents facilitate breeding work because their progenies have a high proportion of clones with the resistant allele. The purpose of this study was to select clones with three to four copies of the Ryadg allele from a population derived from duplex (RyRyryry) crosses and to evaluate the agricultural traits. Testcrosses with a nulliplex genotype (ryryryry) were performed to identify the genotypes for the Ryadg allele, using the SCAR RYSC3 marker. Triplex and quadruplex clones were identified by the marker, but a larger number of progenies of the test-cross must be tested for the confirmation of their genotypes. The agricultural performance of the clones with the Ryadg allele was better than of the control cultivars.