The production of dihaploids and tetraploids with combined quantitative resistance to potato cyst nematode (Globodera pallida) and foliage blight (Phytophthora infestans)

Summary Dihaploids were produced from tetraploids which had resistance to foliage late blight (P. infestans) and had a range of levels of resistance to white potato cyst nematode (PCN) (G. pallida). Twelve of 33 dihaploids tested had useful levels of both resistances, 11 were resistant to blight alone and seven to PCN alone. There were no significant correlations between the resistances of the parents and the mean resistance of their dihaploids, for either character. There was also no correlation between levels of resistance to blight and to PCN. There were significant differences in mean levels of resistance to blight and to PCN between the tetraploid progenies of two dihaploids which possessed combined resistance.