Journal of Taiwan Agricultural Research

Author:Lih-Jiuan Hsieh, Yih-Chang Chang, Chun-Wei Chen and Ting-Fang Hsieh*

Abstract:

    The objective of this study was to evaluate the potential for using rice blast diseased leaves to preserve Pyricularia oryzae. Fresh detached blast diseased leaves and leaves stored at 4℃ for 2, 4 and 5 years were used as the inoculum sources to infect rice seedlings. They were also used to determine the amount of pathogen spores produced on diseased leaves, and the sporulated percentage of the observed lesions. The results showed that after 5-year storage the diseased leaves were still capable of initiating rice blast on rice seedlings. The diseased leaves stored for 2-year had a higher infectivity than those stored for 4 or 5 year, but had no significant difference in infectivity with those on fresh leaves. After soaking in water for 4 hours, the diseased leaves stored for 5 years sporulated continuously for 2 days. The amounts of pathogen spores produced on fresh diseased leaves and leaves stored for 2 or 4 years were not significantly different. The lesions from diseased leaves stored for 5 years were still able to sporulate. The lesions on diseased leaves stored for 2 or 4 years had higher percentage of sporulation than those stored for 5 years, and this ability to sporulate was not significantly different from those on fresh leaves. Our result showed that it is feasible to use diseased leaves stored at 4℃ for more than 2 years as the source of inoculum of P. oryzae.

Key words:Rice, Rice blast, Pyricularia oryzae, Blast-disease-leaf preservation method, Inoculum source

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