Abstract: This paper deals with the studies on effects of a-picolinic acid and the crude toxin filtrate extracted from Pyricularia oryzae on the in vitro embryo culture and seedling growth of Oryza sativa. The results showed: The germination rate and callus induction frequency of embryos and seedling growth were obviously declined along with increasing the concentrations of a-picolinic acid. This tendency was more outstanding in disease-sensitive varieties (strains) . The effects of a -picolinic acid and pathogen crude extracts were similar.