| Fusarium oxysporum is vascular systemic diseases, which is induced by Fusarium Cuba biotypes (Fusarium oxysporum f.sp. cubense). In our country,the majority of the banana growing areas report the disease has happened, because of the diseases, it's rapid spreading and difficult to controlled, the industry of banana has been huge impacted in china, The experimental subjects of this paper is about how to exploit actinomycetes to control Fusarium oxysporum, Collecting soil samples and banana plant samples from Hainan,Guangdong,Sichuan and other places, separating the actinomycetes in these samples, and screening antagonistic bio-control strains from these actinomycetes, and moreover, the strains are confronted with other bio-control strains each other achieving two actinomycetes strains:H1001 and H1010,they are high antagonistic activity stability and can coexist with other biocontrol strains, applying the strains as the research objects, studying its identification, tagging, survival, and Control effect in pot and plot, the main test is as follows:(1),we collected samples of soil and banana plant tissues from banana fusarium wilt of land, abandoned wasteland, mountains rich in organic matter, river mud, etc. in Hainan, Guangzhou, Yunnan, Sichuan. The common and rare actinomycetes,305 strains in total, were separated and purified. And they were antagonized with Fusarium oxysporum f. sp.cubense Race 4, held by mycelium and fermentation products in plate. We screened 26 strains of actinomycetes with strong antagonistic activity, and further to do the coexistence with other biocontrol agents, screened out the purpose of 2 strains of actinomycetes. Also they have been measured to some extent for different Fusarium Specialis.(2), we cultured the strains H1001 and 1010 to observe the morphological characteristics, measured their physiological and biochemical characteristics, strain extracted DNA, determinate the 16S rDNA and phylogenetic analysis, initially identified strain H1001 as a Streptomyces (Streptomyces), strain 1010 was to be no branches acid genus (Amycolatopsis).(3), In order to improve the content of the biocontrol viable and inhibitory activity matter in fermentation broth, through the choice of culture media, optimization of different carbon and nitrogen source, fermentation experiments, Obtained the results of fermentation optimization in the triangular flask and fermenter, the optimum combination of strain H1001 is that 1% carbon source of the glucose,2% nitrogen source of soybean powder,2% inoculation, culture in PH7 and fermentation temperature at 28-30℃for 4 days; and the strain H1010 is that 1.5% carbon source of the glucose,2% nitrogen source of soybean powder,2% inoculation, culture in PH8 and fermentation temperature at 28-30℃for 4 days.(4), In order to understand the survival habits of the biocontrol agents, and the change laws in different media, we markered the biocontrol strains by antibiotic. Accordingly, determined the survival laws of two actinomycetes H1001 and H1010 in different media, The strains showed substantial reduction in the first 7 days, and disappeared completely in the first 42 days. But the biocontrol strains of Bacillus and Trichoderma can survice in organic matter actively.(5), Pot and plot experiments show that biocontrol compound agents composed by different biocontrol strains have a good result in the prevention and treatment of banana wilt disease.It is an effective way to control Fusarium through planting the banana of resistance or tolerance Fusarium, processing in soil fumigation, and using the biocontrol agents and biocontrol fertilizer.In this study, the control effect in Brazil banana reached 26.41%; "Agricultural One banana " reached 47.79%. |
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