Validation of molecular markers for pathogen resistance in potato

DNA markers have a large potential to improve efficiency and precision of conventional plant breeding programmes based on marker-assisted selection (MAS). In our study, we have evaluated the predictive abilities of the SCAR marker RYSC3 and the CAPS marker GP122564 with regard to the PVY resistance genes Ryadg and Rysto, respectively, and of marker TG689 linked to H1 conferring resistance to Globodera rostochiensis and marker HC associated with high levels of G.pallida resistance. The evaluations were made in 28 cultivars and accessions and in 219 progeny genotypes descending from ten different crosses. We observed in all evaluated cultivars and accessions the expected marker patterns according to their phenotypic classification into resistant and susceptible genotypes. However, in part considerable discrepancies were observed when analysing progeny of controlled crosses involving these resistance sources, particularly with respect to H1. Based on these results, practical aspects for the efficient implementation of marker-assisted selection are discussed, which consider the genetic origin of the material, costs aspects and methodology applied.