Evaluation of a SCAR RYSC3 Marker of the Ry adg Gene to Select Resistant Genotypes to Potato Virus Y (PVY) in the INIA Potato Breeding Program

The Potato virus Y (PVY) is distributed worldwide and is one of the most damaging viruses in terms of yield reduction in the potato (Solanum tuberosum L.) crop with losses sometimes reaching 80%. To reduce its impact, there is great interest in obtaining varieties carrying the Ry adg gene that provides extreme resistance to this virus. This could be facilitated with SCAR (sequence characterized amplified region) RYSC3 by molecular marker-assisted selection (MAS). This study compared the effectiveness of the RYSC3 marker in the detection of the Ry adg gene vs. biological tests on populations of the Potato Breeding Program of the Instituto de Investigaciones Agropecuarias (INIA), Chile. Within the group of 71 progenitors, 30 plants had some kind of resistance to the virus, of which 17 were carriers of the RYSC3 marker. These genotypes came from Cornell University, Centro Internacional de la Papa (CIP), Peru, and INIA. The analysis of 460 progenies which came from three different crosses showed that 299 individuals amplified the RYSC3 marker and had the resistant phenotype, with the exception of one plant. Within the group of non-RYSC3 carrier plants, a significant percentage (22.5%) showed a resistant phenotype, indicating that these progenies segregate other R genes (e.g., hypersensitivity) that reduce biological test effectiveness. This high effectiveness (99.7%) in the detection of the Ry adg gene in both parents and segregating progenies, showed that this marker is appropriate in assisting selection of genotypes with extreme PVY-resistance in the potato breeding programs. El Virus Y de la papa (PVY), distribuido mundialmente, es uno de los más dañinos en términos de reducción del rendimiento del cultivo de la papa (Solanum tuberosum L.); llegando a producir pérdidas de hasta 80%. Para reducir su impacto, existe gran interés por obtener variedades portadoras del gen Ry adg que confiere resistencia extrema a este virus. Esto se podría facilitar con la utilización del SCAR RYSC3, mediante selección asistida por marcadores moleculares (MAS). En este estudio se comparó la eficacia del marcador RYSC3 en la detección del gen Ry adg vs. pruebas biológicas, sobre poblaciones del Programa de Mejoramiento Genético de Papa del Instituto de Investigaciones Agropecuarias (INIA), Chile. De un grupo de 71 progenitores analizados, 30 plantas presentaron algún tipo de resistencia al virus, de las cuales 17 son portadores del marcador RYSC3. Estos genotipos provienen de la