| 論文英文摘要 |
Among 331 cultivated soils collected from 14 countries of Taiwan, only 10 soil samples were defined as being suppressive to Rhizoctonia solani AG4 when the germination of monilioid cells was less than 50%. Three of these suppressive soils were collected from central part of Taiwan, two from southern Taiwan, and the other five from eastern Taiwan. Among 10 forest soils tested, three soil samples were suppressive to the pathogen. When six soils with different germination rate were selected to mix with 0.5% chopped potato-soil inoculum as infested soils, two pathogen-suppressive soils and 2 out of 3 semi-suppressive soil were also suppressive to the damping-off of radish seedlings caused by the pathogen AG-4. Based on the data of soil analysis among 62 soil samples, soil pH, organic matter content and soil texture were not correlated to the germination of monilioid cells statistically. Mycelial growth of different anamtomosis groups (AG-1, AG-2, AG-3 and AG-4) varied in different suppressive soils. In the spore germination test of six species of fungi and oomycetes on the tested soil, including Alternaria alternata, Curvularia lunata, Fusarium oxysporum f. sp. cubense, Bipolaris maydis, Phytophthora capsici and Sclerotium rolfsii, the inhibitory spectrums of suppressive soils were also different. |