Abstract

It has been the experience of many Research workers engaged in the study of rice blast disease that considerable difficulties are being encountered in securing sufficient amount of sporulation in culture while multiplying the pathogen for inoculation purposes. It is also known that unless the spore load is of sufficient magnitude successful results are not often obtained in pathogenicity tests. Although certain media like host-leaf extract, rice straw, barley seed, rice polished agar etc., have been suggested by different workers in other countries, it was not always successful to obtain abundant sporulation of the pathogen by using the above mentioned media under conditions existing at this centre. To a certain extent it may perhaps be due to variations in the environmental and other conditions prevailing here. But the suitability of the medium appears to be an important single factor that influences the extent of sporulation. With this object in view, different media were tested to ascertain their suitability for growth and sporulation of Pyricularia oryzae under laboratory conditions. Experi- ments were also conducted to find out the optimum incubation period for maximum sporulation. The size of condia produced in different media was also determined with a view to observe variations if any. The results obtained in these experiments are presented in this paper.

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