INVITRO INOCULATION OF WESTERN WHITE-PINE TISSUE-CULTURE PROPAGULES WITH VEGETATIVE HYPHAE OF CRONARTIUM-RIBICOLA

Propagules of western white pine were inoculated in vitro through intact needles and shoot apex wounds with vegetative hyphae of the blister rust fungus grown from basidiospores in axenic culture. Successfully inoculated propagules showed intracellular haustoria, characteristic of natural inoculation by basidiospores. The opportunity to challenge different tissues of selected host genotypes with cloned replicates of specific rust isolates in vitro may be useful in studying basic processes of resistance and pathogenesis.