Ecological Adaptability Of Bacteria With Biocontrol Potential For Wheat Sharp Eyespot And The Selection Of Biocontrol Synergists

Wheat sharp eyespot, caused by Rhizoctonia cerealis is a serious soil-borne disease which distributes widely in Huanghuai winter wheat area and the middle-lower regions of Yangzi river.It has brought serious harm for wheat production. At present, there is no resistant variety available and the only way to control this disease effectively is chemical control with pesticide, which resulted in environment pollution and emergence of pesticide resistant strains. therefore, the interests of researchers are gradually focused on the safe and efficient biological control. Using the endophytic bacteria for biological control wheat sharp eyespot, which can not only overcome the shortage of chemical control ,but also what's more important is the endophytic bacteria can colonize in plant well.Using the endophytic bacteria treat wheat seed,the endophytic bacteria can infect into the plant as the germination of seeds,and colonize in wheat.For this reason,biological control is more stable,which has a more important theoretical and applications significance.The main purpose of this study is selecting the biocontrol bacteria which has strong environmental adaptability used for agricultural production through the determining of biocontrol adaptability of biocontrol bacteria to wheat sharp eyespot,and selecting biocontrol synergistic matters as synergist used for the development of wheat sharp eyespot biocontrol agents.In this study, three biocontrol strains of wheat sharp eyespot 0-9,0-19, Y10-3 were determined environmental adaptability in three different soils texture and different naturally soils .The experiment was carry out indoor and outdoor, the result showed that strain Y10-3 biocontrol has the least environmental adaptability, and 0-9 showed the best environmental adaptability in these two conditions, both indoor and outdoor,which has potential ability to develop biocontrol agents.The affinity among 0-9,0-19, Y10-3 was measured, results showed that 0-9 and 0-19 are mutually exclusive, Y10-3has a good affinity with the other two biocontrol bacterias. The four matrixs river sand, vermiculite , coal ash and talcum were dealt with three biocontrol bacterias 0-9,0-19,Y10-3 particular concentration respectively,and the survival amount of biocontrol bacterias was detected at regular intervals.The result shows that the vermiculite has the best carrying bacteria ability.The biggest initial carrying bacteria ability to 0-9,0-19,Y10-3 were 7.46×10⁹cfu/g,8.49×10⁹ cfu/g,3.48×10⁹ cfu/g respectively.The survival amount of biocontrol bacterias were 1.63×10⁸ cfu/g,1.39×10⁸ cfu/g,1.44×10⁸ cfu/g three months later in room temperature. The coal ash is the worst in them.In this study,25 substances were added into LB to detect the influence to the growth speed of biocontrol bacteria.The result shows that sucrose, fructose, chitosan, vitamin B1, threonine, leucine, methionine, MgSO₄, NH₄NO₃, (NH₄) 3PO₄, K₂HPO₄, CaCl₂, IAA, GAA can promote the growth speed of 0-9, the chitosan, threonine, leucine, NH₄NO₃, K₂HPO₄, IAA and GAA can promote the growth of biocontrol agents, inhibit the growth of sheath blight fungus, promote sprouting of wheat and seedling growth of triple effect in them.These 7 kinds substances were added to the 0-9 bacterium to biological control wheat sheath blight,the result is better than 0-9 alone with 49.0% .