Distribution And Pathogenicity Of Fusarium Soybean Root Rot In Heilongjiang Province

Soybean Root Rot,as one of the main diseases in soybean cultivation,is widely distributed,harmful and difficult to control.In recent years,due to adverse factors such as soybean monoculture and harsh climatic conditions,the damage caused by soybean root rot has increased annually,and its impact on soybean production and quality has become more apparent.In this study,samples were collected from different soybean planting areas in Heilongjiang Province to isolate and identify pathogens suspected to cause soybean root rot diseases.The study aimed to clarify the pathogenesis of Fusarium spp.through distribution frequency,pathogenicity detection,and soybean variety resistance determination.Moreover,the study aimed to provide data support and important materials for the selection and breeding of high-yield and high-quality diseaseresistant soybean varieties.The main research results presented in this article are as follows:1.Isolation and identification of Fusarium root rot in soybeanIn this paper,a total of 485 root rot pathogens were isolated from samples of diseased soybean strains collected from various planting areas in the province.Using a combination of morphological observation(colony and spore morphology)and molecular biology techniques for joint analysis and identification,nine species were identified:Fusarium brachygibbosum,Fusarium equiseti,Fusarium globosum,Fusarium graminearum,Fusarium incarnatum,Fusarium oxysporum,Fusarium proliferatum,Fusarium solani,and Fusarium tricinctum.Among these,Fusarium oxysporum exhibited the highest separation frequency(46.80%),followed by Fusarium solani(19.38%).2.F.oxysporum RAPD analysisThe RAPD analysis of F.oxysporum involved filtering 10 primers with clear,highly polymorphic detection rates that differed stably from published RAPD primers.Thirtythree strains from various soybean planting areas were analyzed,and 54.43% of the polymorphism sites were amplified.Based on the RAPD diagram analysis,a UPGMA analysis was conducted on the 33 strains,dividing them into eight major categories using a genetic similarity coefficient of 0.80 as a threshold.Our results revealed relatively small genetic differentiation within populations.3.Study on the pathogenicity of different Fusarium speciesThe pathogenicity of different Fusarium spp.on soybean plants was investigated using the greenhouse potting experimental method.After 21 days of inoculation with Fusarium species,the aboveground and underground growth of soybean seedlings was affected to varying degrees.Of the 9 different Fusarium species tested,F.oxysporum and F.solani were found to be highly pathogenic,while F.incarnatum displayed weak disease and was of medium strength in the other treatment groups.4.Identification of resistance to F.oxysporum and F.solani in different soybean varietiesThe resistance of 21 soybean cultivars to F.oxysporum and F.solani was assessed,with most varieties showing certain resistance.The resistance of the tested soybean varieties to different strains in the Fusarium species exhibited rich diversity,and the resistance of the same soybean variety to different Fusarium species was significantly different.Among the identified varieties,57.14% of soybeans displayed high resistance to F.oxysporum,while medium resistance accounted for 14.29%,and susceptible soybeans accounted for 28.57%.In the screening for resistance to F.solani,the proportions of soybean varieties with high resistance,medium resistance,and susceptibility were 61.90%,33.33%,and 4.76%,respectively.Dongnong 51 was the most resistant to both F.oxysporum and F.solani.