Damage analysis of rice panicle blast on disease occurrence time and severity

초록

The structural differences between healthy and diseased panicle necks caused by Pyricularia oryzae were observed using electron-microscope. In the diseased panicle neck, the infection hyphae of the rice blast pathogen grew through the sclerenchymatous fiber tissue and reached to the central internal lacuna. Since the pathogen grew through the sclerenchymatous fiber tissues, the vascular bundle composed with xylem and phloem had been destroyed and finally the nutrients from the leaf and stem were not able to be transported into the grains. Infection of panicle base by the blast pathogen until 20 days after heading caused more than 50% of yield loss in both Jinmibyeo and Chucheongbyeo. There was a positive correlation between incidence of the panicle blast and rice yield losses. The regression equations between incidence of the panicle blast and yield losses were y = -3.61+496.7 (R2 = 0.70) in Jinmibyeo and y = -3.93+520.2 (R2 = 0.82) in Juanbyeo. The panicle blast caused deterioration of grain quality. Healthy grain rate was reduced by increase of panicle blast infection. © The Korean Society of Plant Pathology.

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