The Preliminary Study On The Effect Of Bacillus Subtilis BSA-6Strain On Control Of Fusarium Wilt Of Banana

Following by rice, wheat and corn as four of largest food of the world, Bananas are deeply loved by people all over the world because of its sweet taste. However, the quality and production reduced severely in China because of banana panama wilt. Therefore, seeking a green and pollution control method become an important topic in the process of the development of the banana industry. As biological control is safe for humans and environment, it attracts more and more attention. We sceened a strain stored in our laborary which has good control efficiency against Fusarium oxysporum f. sp. Cubense. through a series of experiments we drew the following conclusions.(1) We screened BSA-6strain which has good control efficiency against Fusarium oxysporum f. sp. cubense stored in our laborary. Though microbial morphological, physiological and biochemical characteristics and16SrDNA identification, we evaluated it preliminarily as Bacillus subtilis.(2) By using the method of turbidimetry, it can be concluded that the most appropriate growing conditions for the strain is35℃in temperature,7.0of initial pH,210r/min of rotating speed,200ml/500ml of loaded liquid and6%of initial inoculation size. Antagonistic substances in the BSA-6fermentation liquor is exocytosis type metabolin, which mainly exists in the supernatant fluid. A certain concentration of the BSA-6fermentation liquor has a accelerative effect on the sprouting and rooting of the cucumber seeds.(3) Using Rifampicin (Rif) to mark the BSA-6’s resistance to drugs,300ug/ml Rifampicin-resistant BSA-6A can be abtained eventually. The research showed that BSA-6R would live better with Kingo refined organic fertilizer. After fertilizering different components of BSA-6fermentation liquor, the thallus and the fermentation liquor can both improve the PAI、POD、PPO enzymatic activity of banana obviously and strenghten the resistant ability of banana effectively.(4) According to single factor experiment and orthogonal test, it can be concluded that the most suitable solid fermentation medium concludes cereal chaff150g, bran850g, glucose50g, yeast extract40g, Na2HPO43g, NaH2PO41g, H2O1.5L. Inoculating seed solution of16h at the percent of6%, fermentating48h at36℃, the spore production can achieve63.85×109CFU/g.(5) Potting test results indicated that using microbial fertilizer will have a good protection against banana wilt and the compound fertilizerⅢ’s protection rate is69.59%. Plot experiment results indicated that different microbial fertilizers’ protection rate varies significantly between different banana kinds. Combining microbial fertilizer and resistant breed can prevent against banana wilt better.