Effect Of Inorganic Elements (N,P,K,Zn) On The Characteristics With Cultural And Microsclerotia Of Verticillhun Dahliae

Cotton Verticillium Wilt that caused by Verticillium dahliae Kleb is one of the mostimportant diseases of cotton production in China. In recent years, Cotton Verticillium Wilt onthe cotton production became more and more serious harm, controlling verticillium wilt ofcotton was a difficult and key work in cotton production.N, P, K, Zn was required for the mainelements of cotton growth.The research had carried out in relationship between fertilizerapplication and verticillium wilt of cotton, but had no found the report which the effect offertilizer application in V. dahliae. In this study，to determine the main V. dahliae groups infields by isolation strains from infected plants. Screening the optimum medium ofmicrosclerotia formation and colony growth.The effect of the elements N, P, K, and Zn on thecolony growth, microsclerotia formation and germination were studied using cultivationmethod of culture dish, with the exploration of the relationship between inorganic elementsand V. Dahliae. The main results were shown as below:1.20strains of V. dahliae were isolated from the disease field, with12strains ofsclerotium type (AVH)and8strains of middle type (AVM). All the plants of cotton symptomwere yellowing by infecting in strains. The pathogenicity assessment had not fand the strainsof defoliating type.2.According to the assay of screening the optimum medium: oat medium modified, M1and BMM were the ideal culture mediums for microsclerotia formation and colony growth.The medium of Czapek were advantageous to mycelial propagation.3.The N content in the range of0.33~0.82g/L promoted the growth of colony,and in0.33g/L the most conducive to microsclerotia formation. The N content in the range of0~0.82g/L,microsclerotia diameter became smaller with increasing content increased. The microsclerotiagermination rate became lower when the N content less than0.33g/L.4.The content of P(P2O5) caused the colony with the increase of concentration andgrowth rate slowed down gradually in the concentration range of0~1.98g/L. The content ofP(P2O5) in the concentration range of0.2~0.4g/L could promote microsclerotia produced more. P(P2O5) in the concentration range of0~0.2g/L, microsclerotia diameter got smallerwith the increase in phosphorus content, and the microsclerotiia germination rate becamelower when the content less than0.2g/L.5.The content of K(K2O) could cause in favor of colony growth in0.13~12.63g/L. Thecontent of K(K2O) produced a lot of microsclerotia in the concentration range of0.13~0.63g/L. The content of K(K2O) had no effect on microsclerotia diameter and microsclerotiagermination rate.6.Zn content in the concentration range of0~0.11g/L had not affected on the colonygrowth. When the content of Zn in the range0~0.23g/L, microsclerotia formation decreasedwith the increase of concentration and microsclerotia diameter became samller. The content ofZn had no effect on microsclerotia germination rate.