'Asker' as Source of Resistance to Raspberry Root Rot

The cultivar 'Asker' (syn. 'Winklers Samling') is one source of resistance to raspberry root rot (Phytophthora rubi) in red raspberry (Rubus idaeus). Resistance to root rot in F1 seedlings with 'Asker' as mother parent was tested by inoculation with P. rubi in hydroponic culture. Disease symptoms on roots and root regeneration after inoculation showed a continuous distribution among the seedlings, with no seedling genotypes significantly exceeding the resistant control 'Asker' or being inferior to the susceptible control 'Glen Moy' in these characters.