Abstract

                                A toxic principle was found in the culture filtrate of Piricularia oryzae Cav. the rice blast pathogen, when grown in Czapek-Dox liquid medium. The toxin temporarily inhibited the germination of blast susceptible varieties of rice. It also inhibited plumule elongation in blast susceptible rice varieties, but in blast resistant varieties there was no significant inhibition. The toxin did not affect seeds of Sorghum vulgare, Eleusine coracana, Pennisetum typhoides and Setaria italica. The possibility of utilising the toxin for a preliminary screening of rice varieties for resistance to the blast diseases is indicated.

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