Isolation And Identification Of Pathogens Of Lentil(Lens Culinaris) Root Rot And Study On Their Pathogenicity To Medicago Sativa,Onobrychis Viciaefolia And Astragalus

Lentil(Lens culinaris) is alimentarn crop comonly planted in Huining and other counties, Gansu Province. It is used in rotation and eutrophytion. However, production of lentil rupidly delined rencently years as many plants died. Some leguminous forage plants such as Medicago sativa, Onobrychis viciaefolia, Astragalus adsurgens were alternated in these siol in this situation and some govermental policy such as grain land for green were implemented. The object of this thesis was to study the pathogens of lentil in Huining area, and test the pathogenicity of these pathogens to these forage plants. Some resultes were as follows:1. Mortality of lentil in Huining was43.2%. The reason was Fusarium root rot. Disease incidence was58.4%. The symptoms characterized as aboveground died since root brown rot.2. Fusarium spp. were identified as Fusarium oxysporum, F. equiseti and F. acuminatum combined morphological and ITS analysis. The isolation frequenties were55%,18%and9%.3. Four plant species were infected by the three Fusarium species in the pot experiment used soil collected from Huining. This indicates the pathogens of lentil root rot was soilborne, and have virulence to the three leguminous forages.4. The three Fusarium species decreased root length and root weight significantly (P<0.05) both in pathogenicity test and pot experiment with contaminative soil.In conclusion, M. sativa, O. viciaefolia, A. adsurgens would be infect by the pathogens of lentil root rot in soil after grown lentil with root rot. It is necessary to pay much attention to root rot of leguminous forages practically.