Stacking host resistance genes to control Globodera pallida populations with different virulence

Potato Cyst Nematodes (PCN) are a globally important and economically extremely damaging potato pest. Chemical control has limited impact and cannot clear a field of PCN, but genetic resistance in potatoes is an effective and important part of natural management of PCN. There are two closely related species of PCN; Globodera rostochiensis against which the H1 resistance gene from S. tuberosum ssp. andigena (CPC 1673) has proven effective in Europe for several decades, and G. pallida for which potato varieties with resistance are also commercially available. However, G. pallida resistant genotypes are mainly limited to processing varieties and most varieties grown are still susceptible to the species. The limited number of suitable varieties with resistance against G. pallida has led to its spread throughout the UK and now infestations in Scottish seed land are threatening the future of potato seed production. Novel potato genotypes with resistance against G. pallida sometimes combine PCN resistances from more than one parental source. Multiplication of a panel of G. pallida populations which differ in virulence against host species were compared on recently developed breeding lines with single or stacked resistance genes. Potato genotypes with multiple resistance genes show reduced multiplication in G. pallida pathotypes that were able to overcome a single resistance gene.