Effect of Different Inoculation Methods on Pathogenicity of Fusarium proliferatum to Alfalfa

[Objectives] To find out the suitable inoculation method for Fusarium proliferatum. [Methods] Longmu 801 and TG4 were inoculated with rice grain-based inoculum at the bud and seedling stages and with root irrigation at the seedling stage, respectively, and then, the plant height, aboveground biomass, underground biomass, incidence rate and disease index of the alfalfa were determined to conduct comprehensive resistance evaluation. [Results] There was obvious difference in disease resistance between the two alfalfa varieties. Among the three inoculation methods, the relative plant height, relative aboveground biomass and relative underground biomass of Longmu 801 differed insignificantly (P>0.05), all around 100. There were significant differences in TG4 among different inoculation methods (P<0.05). The incidence rates and disease indices of Longmu 801 and TG4 inoculated with rice grain-based inoculum at the bud stage were the highest, and their incidence rates and disease indices were 73.3% and 100%, and 40 and 60, respectively, significantly higher than those under the other two inoculation methods. The incidence rates and disease indices of Longmu 801 and TG4 inoculated with rice grain-based inoculum at the seedling stage were the lowest, and their incidence rates and disease indices were 0% and 13.30%, and 0 and 5.33, respectively, significantly lower than those under the other two inoculation methods. [Conclusions] The inoculation time and inoculation method of the pathogen both affect the inoculation effect. Among the three inoculation methods, the inoculation with rice grain-based inoculum at the bud stage is the most pathogenic to alfalfa seedlings, and can be popularized in the resistance evaluation of alfalfa to root diseases.