Resistance Identification Of Peanut Varieties With Crude Toxin Of Ralstonia Solanacearum Caused Peanut Wilt

The crude toxin of Ralstonia solanacearum was applied in the disease resistance of peanut varieties. The paper was made up of four parts: Ⅰ. Resistance of peanut varieties or lines to R. solanacearum in the field. Ⅱ. The appropriate conditions for the production of crude toxin of R. solanacearum caused peanut bacterial wilt and its sensitivity to thermal treatment and ultraviolet ray. Ⅲ. The disease resistance of peanut was tested with the crude toxins of R. solanacearum, Ⅳ. Reaction of different explants of peanut cultured in vitro to crude toxin of R. solanacearum.224 varieties or lines of peanut were tested by inoculation of dip seeds in bacterial suspension for their resistance to R. solanacearum in the field. The results showed that no variety and line were high resistance. 67 were moderate, such as Jinhual012, QuanhualO, Quanhua646, Yueyoul93 and 38F5-45-21-CS1 etc, which accounted for 29.91% of the test varieties or lines. The sensitive varieties and lines were accounted for 70.09%. The different resistance among the varieties or lines were remarkable.The crude toxin of R. solanacearum caused peanut bacterial wilt was studied in different cultural conditions, its sensitivity to thermal treatment and ultraviolet ray tested also.The results showed that the appropriate condition for the production of crude toxin of the bacteria was that cultural temperature and pH value were 25-28℃ and 7 and cultural days were 3. But no significant difference among crude toxin abtained under different cultural concentrations.The crude toxin is sensitive to thermal treatment and it's biological activity decreased 89.82% at 100℃ waterbath for one hour. The crude toxin was not sensitive to ultraviolet ray and it's biologicalactivity was not changed under ultraviolet light for 30min, 60min, 90min and 120min.The disease resistance of peanut was tested with R. solanacearum or its crude toxin. The results showed that there was significantly positive correlations between the disease index of R. solanacearum infection and wilting degree of crude toxins treatment (r =0.888). The disease resistance of five different varieties was determined with crude toxin of R. solanacearum with the methods of leaf-cutting,stabbing,injecting,spring and root-irrigating, the results showed that the method of cutting leaf was the best inoculating way.The test of crude toxin of R. solanacearum to peanut embryonic root growth and separated leaf was studied.The result showed that peanut embryonic root growth was reduced by crude toxin significantly.Different reactions of separated leaf to the toxin was observed when different peanut varieties were used.The reaction of different peanut varieties to the toxin was significantly different. Embryonic root growth and separated leaf with toxin provided two cheap and exact tools to identify peanut resistance to the pathogen.Reaction of different explants of peanut cultured in vitro to crude toxin of R. solanacearum was studied.the results showed that the different disease resistance was observed on tissue cultural seedlings of different peanut varieties with the methods of painting toxin onto the medium and adding toxin into the medium. The frequency of callus formation by the toxin showed that the percentage of callus formation of peanut leaf decrease, as the concentration of the crude toxin increases, but the difference of varieties was not significience.The test of frequency of brown callus ofdifferent peanut callus showed that the callus from susceptible genotyes were sensitive .which browned rapidly and collapsed heavily, in comparision with that from resistant ones.The resistance in vitro showed a tendency to be identical with the resistance in the field.