Identification Of Broad Bean Chocolate Spot Pathogen Species And Screening Of Resistance Resources In Qinghai Province

Broad bean is one of the important edible beans in China,Qinghai province is one of the main areas of broad beans,chocolate spot disease is an important worldwide disease on broad bean,It seriously affects the yield and quality of broad beans.The study on the pathogen species and biological characteristics of broad bean scab,testing the sensitivity of the pathogen to common fungicides,and screening the germplasm resources of broad bean chocolate spot can provide a theoretical basis for the comprehensive prevention and control of the disease.This study through morphological observation and molecular biology technology,isolated and identified broad bean disease samples from the three prefectures and cities of Qinghai province the highest frequency of the representative strain of spore isolate ZS045B biological characteristics and nine kinds of agent sensitivity test,and 34 broad bean germplasm resources in Qinghai province disease resistance identification,the results are as follows:A total of 268 pathogen samples were isolated from 83 villages in 11 districts and counties in Qinghai province,After the initial classification of the fungus strains.The morphological and molecular characterization of 33 of these fungus,the results showed that a total of nine pathogens were found,three of them are reported pathogens:Botrytis cinerea,Boytrytis fabae,Boytrytis fabae,and Botrytis fabiopsis.In addition,six species of pathogens were first found in China:Botrytis euroamericana,Botrytis paeonia,Botrytis caroliniana,Botrytis eucalypti,Sclerotinia sclerotiorum and unidentified species Botrytis sp.The growth rate of strain ZS045B was tested under different carbon sources and nitrogen sources by using four carbon sources（glucose,soluble starch,maltose,and sucrose）and four nitrogen sources（sodium nitrate,ammonium sulfate,urea,and yeast）.The effect of different temperatures on colony growth was tested at seven temperatures（4℃,6℃,15℃,20℃,25℃,28℃,and 30℃）.The results show that the best carbon source of the strain is glucose,the best nitrogen source is ammonium sulfate,urea has inhibited the strain,the optimal growth temperature is between 20℃and 25℃,this fungi stopped growth at 4℃,but not its inhibitory low temperature,as a colony preservation temperature,stop growth at 30℃,but not its lethal temperature.All nine fungicides showed inhibitory effects on ZS045B,the large differences in sensitivity,pathogens are more sensitive to the oxone cream and manganese zinc.The virulence of the agent is greater,The EC₅₀ is less than 5 mg/L,Corrot,clean,azoletheriacyl,xamine manganese salt and pyrizoens ester virulence second,Its 17 mg/L<EC₅₀<40 mg/L,The azole and phenylxazole have less virulence,the pathogen had the least reported susceptibility.Its 59mg/L<EC₅₀<70 mg/L,Oxxone cream urecyanide and manganese zinc can be used as primary agents for field testing.From 2015 to 2019,the resistance was identified by field natural disease in four site.To evaluate the resistance of 34 broad bean resources to chocolate spot of broad bean in Qinghai province.By using GGE biplot,the optimal genotype and test environment were selected.As a result,‘VF4’,‘VF5’,‘VF6’the resistance and stability of three resources to Vicia faba chocolate spot were better than those of the other 31 resources,it can be cultivated as a resource against broad bean chocolate spot.The low-altitude and middle-altitude ecological areas represented by Dayou mountains and Plant Protection Institute have good differentiation and representation.The high altitude ecological area represented by the test point of Nanmen Gorge has better differentiation,but less representative,it can be used to eliminate resources with poor resistance and unstable resistance.