Mass Screening of Young Strawberry Seedlings for Resistance to Phytophthora fragaria Hickman1

Abstract

Abstract Young strawberry (Fragaria × ananassa Duch.) seedlings were screened over a 4-year period for resistance to a composite of races of the red stele root rot causal organism, Phytophthora fragariae. A mixture of mycelia of 5 races of the organism, agar and water used as a root dip at the time of planting into sand on 6- to 8-week-old seedlings gave uniform results in the elimination of susceptible seedlings approximately five months later. The technique lends itself to efficient and effective mass screening of strawberry seedlings for relative resistance to P. fragariae.