Validation and Implementation of Marker-Assisted Selection (MAS) for PVY Resistance (Ry adg gene) in a Tetraploid Potato Breeding Program

Abstract

The gene Ry adg from S. tuberosum ssp. andigena provides extreme resistance to PVY. This gene has been genetically mapped to chromosome XI and linked PCRbased DNA markers have been identified. Advanced tetraploid russeted potato clones developed by the U.S. Pacific Northwest Potato Breeding ('Tri-State') Program with Ry adg PVY resistance were used in this study. The objective of this work was to assess the usefulness of molecular markers linked to Ry adg as a tool for selecting PVY resistance in a tetraploid potato breeding program. To achieve this, a full-sib tetraploid population segregating for Ry adg was screened with molecular markers linked to Ry adg , artificially inoculated with PVY O and evaluated in the greenhouse. A large percentage (96.4%) of the segregating lines showed coincidence between molecular markers and ELISA results at 40 days after inoculation. This justifies the use of molecular markers as an alternative to artificial inoculation followed by ELISA. Segregation (resistant vs. susceptible) based on ELISA and molecular marker results in the full-sib population indicated the presence of Ry adg as a simplex in the PVY resistant parent OR00030-1. Additional full-sib populations segregating for the Ry adg gene coming from OR00030-1 and from a related clone, AOR00628-3, were evaluated under field conditions. MAS can be used as a fast and efficient tool to select for PVY resistance, reducing the number of PVY susceptible lines retained for succeeding field evaluations, and thereby increasing the odds of generating PVY resistant potato varieties.Resumen El gen Ry adg de S. tuberosum ssp. andígena ofrece resistencia extrema contra el virus Y de la papa (PVY). Este gen ha sido genéticamente mapeado en el cromosoma XI y se han identificado marcadores ligados de ADN basado en PCR (reacción en cadena de la polimerasa). Clones avanzados tetraploides de papa rugosas, desarrollados por el Programa de Mejoramiento del Pacífico Noroeste de los Estados Unidos (`Tri-State´) con resistencia Ry adg al PVY fueron utilizados en este estudio. El objetivo de este trabajo fue evaluar la utilidad de los marcadores moleculares ligados a Ry adg , como una herramienta para seleccionar resistencia al PVY en un programa de mejoramiento de papa tetraploide. Para lograr esto, una población tetraploide de hermanos completos, segregantes para Ry adg fue tamizada mediante marcadores moleculares ligados al Ry adg , inoculada artificialmente con PVY o y Am. evaluada en invernadero. Un alto porcentaje (96.4%) de las líneas segregantes mostró coincidencia entre los marcadores moleculares y los resultados de ELISA 40 días después de la inoculación. Esto justifica el uso de marcadores moleculares como una alternativa a la inoculación artificial seguida por ELISA. La segregación (resistente vs. susceptible) basada en ELISA y los resultados de los marcadores moleculares en la población de hermanos completos, indicó la presencia de Ry adg como un simplex en el progenitor PVY resistente OR00030-1. Poblaciones adicionales de hermanos comp...

Detection of molecular markers linked to Ry genes in potato germplasm for marker-assisted selection for extreme resistance to PVY in AAFC’s potato breeding program

“…In spite of the small sample size, this assessment, together with studies by others (e.g., Ottoman et al 2009), shows the effectiveness of the marker RYSC3-assisted selection for Ry adgconferred ER, providing the marker is present in at least one of the two parents. It is notable that in the study by Ottoman et al (2009), a low level of discrepancies (3.6%) between phenotype and genotype was observed in a segregating population, suggesting that new markers with a higher linkage to Ry adg are desired.…”

Potato virus Y: An Evolving Concern for Potato Crops in the United States and Canada

“…Recent releases from this program have included information regarding PVY strain reactions (90). As more breeding programs recognize the value of PVY resistance (66,98), there is a need to develop some standard materials and protocols that will allow potato genotypes to be evaluated properly against a range of PVY strains that predominate in the regions of the country that will likely produce the released cultivar. Evaluating PVY responses as part of the field testing of advanced breeding lines allows breeders, growers, and seed certification programs to identify potential problems and discover new sources of resistance.…”

“…Some older cultivars such as Kennebec, Sebago, and Katahdin, which have some level of field resistance conferred by unknown genes to some PVY strains, have been replaced by other cultivars that do not have PVY resistance. However, breeding programs in the Western United States have been looking more carefully at incorporating PVY resistance genes related to those in materials used to develop 'Eva' (66,98). These programs have also been testing new cultivar releases for resistance to the range of PVY strains, and some have significant levels of resistance against PVY O (64,90).…”

Allele dosage of PVY resistance genes in potato clones using molecular markers

“…When comparing the ELISA test with the marker RYSC3, studies demonstrate high coincidence, greater than 95%, between the positive results for resistance to PVY (Ottoman et al 2009). These results evidence the importance of the discovery, validation and use of molecular markers as a tool to make breeding programs more efficient.…”