| Summary: | 碩士 === 國立虎尾科技大學 === 生物科技研究所 === 100 === Damping-off is one of the most serious diseases of cabbage seedlings in Taiwan. The disease was caused by two common soilborne pathogens, such as Rhizoctonia solani and Pythium aphanidermatum. The infected seedlings of cabbage could be killed either before or after emerging from the soil. The common symptoms were cankers, brown lesions on stems, or root rot on roots if they can still survive. Therefore, this research tried to study on the effect of seed coating treated by Trichoderma spp. on seed germination, seedling growth and disease incidence of cabbage. The cabbage seeds were coated by using mixture of methyl cellulose and carboxymethyl cellulose as the adhesives, diatomaceous soil as the filler and the spore of Trichoderma spp. as protectant The seed germination, plant growth and disease incidence were detected by bioassay with Rhizoctonia solani and Pythium aphanidermatum in plate medium and greenhouse. The results indicated that Trichoderma spp. could enhance the germination rate in aging seeds of cabbage. The germination rates for untreated seeds, and treated seperatively with Trichoderma virens LN-PA R4-2 and Trichoderma harzianum ET S3-2-3 were 55%, 75% and 68%, respectively. For the dural tests, the result showed that T. virens LN- PA R4-2 and T. harzianum ET S3-2-3 could inhibit seperatively the mycelial growth of R. solani AG-4 and P. aphanidermatum. Furthermore, for plate assay, the results showed that cabbage seeds coated by Trichoderma spp. could reduce considerably the disease incidence of damping-off. In green house test, the results also confirmed that cabbage seeds coated with T. virens LN- PA R4-2 and T. harzianum ET S3-2-3 could significantly reduce the damping-off disease in seeding stage. To get together, the treatment of seed coating of cabbage using by Trichoderma strains as protectant can be used as an alternative method for chemical control of plant diseases.
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