벼의 잎 ·목 稻熱病에 대한 抵抗性의 比較 = Differences in Reactions of Leaf and Neck of Rice Plants to Rice Blast

다국어 초록 (Multilingual Abstract)

1. Differences in reactions of leaf and neck of rice plants to rice blast among four rice cultivars were observed in a paddy field. Cultivars Jinheung and Milyang 23 showed susceptible and resistant reactions, respectively, on both leaf and neck. Cultivar Norin 6 was susceptible to leaf blast and became intermediately resistant to neck blast whereas cultivar Ginga showed resistant and intermediately resistant reactions on leaf and neck, respectively.
2. Three different heading dates at 5 to 8 day intervals were induced by transplanting seedlings of four cultivars from seedling beds to a paddy field three times at 9 to 10 day intervals. When blast severity was compared within cultivars, leaf blast severity increased as heading dates became late. However, neck blast severity was greater in plots with early heading dates than those with late heading dates.
3. Spore germination of two isolates of Pyricularia oryzae in tissue extracts from leaf and neck of four rice cultivars indicated significant interactions between cultivars and isolates. However, spore germinations in leaf and neck extracts were not significantly different. Mean degree of hyphal growth of four P. oryzae isolates on the sheath adaxial epidermis indicated significant interactions between cultivars and isolates.
4. Some anatomical characteristics of leaf and neck of four cultivars did not have apparent relationship with the reactions of four cultivars to rice blast in the paddy field. Also, the amounts of the total nitrogen, sugar, P₂O??, and SiO in flag leaf and neck were not significantly different among four cultivars and did not seem to affect changes in reactions of cultivars Norin 6 and Ginga to leaf and neck blasts observed in the paddy field.