Study On The Antagonistic Mechanism To Pathogens Of Soybean Root Rot And Preparation Of Trichoderma Spp.

Trichoderma spp. is considered one of the most promising biological control factors, and has well inhibition to pathogens of soybean root rot. To make early for the production of Trichoderma spp. by further developping and utilizing, six strains of Trichoderma spp. were indentified and studied to the pathogens of soybean root rot in the study. Three strains which were selected from six were initially used for exploring the development of preparation. As the same time, the field efficiency of Trichoderma preparation to soybean root rot were also studied in the paper. The experimental results were as follows:1. The inhibition of Trichoderma spp. to pathogens of soybean root rot were studied by the space competition, parasitism and antibiosis. The results showed that Trichoderma spp. can inhibite the growth of pathogens of soybean root rot through confronting each other, cultivating face to face, cultivating in cellophane film. Confront culture results showed that Trichoderma had stronger advantages of spatial competion to the pathogens of soybean root rot. The microscopic observation showed that six strains of Trichoderma spp. had the significant parasitic effect against Rhizoctonia solani, Pythium ultimum, Fusarium oxysporum and Fusarium avenaceum. Trichoderma spp. was parasitized on the mycelia by the way of spiral wound, adhering, as while, surrounding the mycelia through producing small hyphae, which could finally cause the disintegration and death of pathogens. The hard volatile metabolite in the metabolites of Trichoderma spp was an important antibacterial substance which had the significant antibacterial effect on the pathogens of soybean root rot.2. Six strains of Trichoderma spp were identified by the methods of molecular biology and morphological. Six different ITS sequences have been got by PCR and sequencing. Through inputting TrichOKEY and TrichBLAST in the ITSH website, the comparative analysis of sequence and combination with morphological identification of Trichoderma spp, T20A, T20G, T38D, T61F, and T78E have been determined to be different strains of Trichoderma koningiopsis s and T115D to be Trichoderma longibrachiaum.3. Liquid and Solid Fermentation conditions of Trichoderma T38D, T78E, and T115D have been selected and optimized by using orthogonal test. The favorable training matrix and conditions that Trichoderma spp quickly produced large number of spores have been determined. Trichoderma granules had been prepared.4. The field pathogens control results of Trichoderma preparation to the soybean root rot showed that the occurrence of soybean root rot can be reduced by Trichoderma preparation. And the effect of mix Trichoderma preparation was better than single Trichoderma preparation; the controlling effect was 42.79%, lower than the Chemica Control (55.63%). The control effect was 48.18% by used mix Trichoderma preparation mixed with 1/2 dose of the chemicals. In different periods, the results of soybean morphological index survey and the yield estimation showed that the growth of soybean could be promoted by Trichoderma preparation, and its yield also improved.