| The goal of this project was to optimize the growing conditions, and to develop an application method to use Trichoderma longibrachiatum T6 as a biocontrol agent. The growing conditions were optimized by selecting the appropriate solid growth media and fermentation conditions. The application method was selected by looking at different carriers that were water soluble; the best carrier was selected based on storage longevity. Both, the growing method and the best carrier were tested for their effect on disease resistance. The results obtained are as follows:1. Optimization of spore production of T. longibrachiatum T6: Screening for the solid medium found that the best formulation for culture medium is the peat, vermiculite and manure with in a 1:1:1 ration; in this formulation T. longibrachiatum can reach spore production of 7.12 × 108 cfu·g-1. A single factor tests indicated that the optimal fermentation conditions were: moisture content of 60%; inoculation amount of 30%; air permeability is 9 layer gauze; temperature 28 ℃; p H of 5.6. Result showed that the effects of moisture content, inoculation amount and breathability on the number of spore production of T. longibrachiatum T6 were signif icant among the five factors.2. Optimization and analys is the number of spores production of T. longibrachiatum T6 bio-agents by response surface method. Optimized fermentation conditions by the response surface methodology were moisture content of 64%, inoculation amount of 57%, air permeability of 9 layer gauze. Under these optimal conditions, the number of spores pr oduction of T. longibrachiatum T6 reached up to 8.80841 cfu·g-1. Finally, the consistent results between the predicted value and actual value indicated the model in this study is feasible.3. Development of T. longibrachiatum T6 water dispersible granules: After screening several aid types and the storage stability was measured, the results indicated that the best formulation(mass fraction) was: hydroxymethyl cellulose(UV protective agents) 0.5%; calcium carbonate(Stabilizing agents) 4%; vinyl pyrrolidone(PVP, Binders) 5%; soluble starch(Disintegrating agents)5%; attapulgite(Carriers)5%; and sodium lauryl sulfate(surfactant agents)5%. Quality assays showed that spore production of T. longibrachiatum T6 in this water dispersible granules was 5.6×10 8 cfu·g-1, the suspension rate of the production was 53%, p H was 6.0, the moisture amount was 3.5%, the wetting time was 52 s, the stability at low temperature of 4 ± 2 ℃ was signif icantly higher than that at room temperature 25 ℃. These values are the suggested formulation standards.4. Analysis of T. longibrachiatum T6 water dispersible granules effectiveness on crop growth: The promoting effects of the biocontrol formulation were tested by looking at the morphological and physiological growth indexes of cucumber, tomato, pepper, rapeseed, and Chinese cabbage. The results suggested that different proportions of T. longibrachiatum T6 agents could signif icantly increase the content of substances and enzyme activities related to the growth and resistance of cucumber; particularly when the Trichoderma water dispersible granules and soil are mixed according to the ratio of 1:50. When it was 1:50, the relative growth rates of plant height, fresh weight, root fresh weight, base stem diameter, root length were 50.07%, 64.03%, 77.22%, 73.88% and 41.45%. The relative growth rates of chlorophyll and soluble protein content were 46.16% and 50.67%. The activities of peroxidase and phenylalanine ammonia were signif icantly higher than in the control plants; and the relative grow th rates were 57.63% and 61.95%. Pot experiment showed that crop plants are robust, tall, dark green leaves, and have a well-developed root system.5. Analysis of T. longibrachiatum T6 water dispersible granules on crop protection: The results indicated that T. longibrachiatum T6 agents has a good control effect of powdery mildew and blight on cucumber without any injury, which can control the disease spread and relative control effect was reached 53.8%. A pot experiment indicated that T. longibrachiatum T6 biocontrol agents has a good control effect on pepper seedling blight and root rot of rapeseed, which can control the disease spread and relative control effect was reached 53.8% and 43.1%. The biocontrol agent is safe and harmless to the tested plants. |
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