Studies Of Biologic Characteristics Of Pathogen,Fungicide Virulence And Screening Of Resistant Germplasm In Melon

Melon is one of the top ten fruits in the world.It has been popular all over the world,which has a delicious flavor and rich nutrition.In the process of melon production,gummy stem blight（Gsb）is one of the serious diseases that endanger the quality and yield of melon fruit.In severe cases,it can even directly cause huge economic losses.It is a great significance for melon production and disease-resistant breeding which fungicides of anti-Gsb were screened and which germplasm were identified for Gsb resistance.In order to control Gsb by chemical fungicides and breed resistance Gsb varieties,it had been carried out in this experiment that were pathogen identification,biological characteristics.Screening of effective fungicides for Gsb and resistant germplasm identification by marker assistant selection.The main conclusions are as follows:（1）Pathogen collected in greenhouse was Stagonosporopsis cucurbitacearum by cultivation characteristics,morphology identification,re-inoculation and molecular identification by ITS sequence.（2）The suitable composition of medium and factors were screened for S.cucurbitacearum.The suitable medium was starch medium.Twenty-five centigrade was optimum growth temperature,and optimum p H value was 6.Twenty-four light was suitable.The suitable compositions of carbon source nitrogen source were soluble starch,yeast and peptone respectively.（3）The regression equation was Y=0.9957x+6.9351,and correlation coefficient was 0.9387according to results of fungicide inhibition experiment in S.cucurbitacearum.Two fungicides were screened,that was acute inhibition for S.cucurbitacearum.Luna Sensation and merivon fungicides were gotten good inhibition effects,and EC₅₀ values were 0.0114μg/ml and0.0747μg/ml respectively.（4）Three germplasms which contained Gsb-1 gene were screened among twenty-three germplasms by molecular marker selection...