Physiological Differentiation Of Exerohilum Turcicum And The Resistance Of Maize To Northern Corn Leaf Blight

Northern corn leaf blight is an important disease which hazards maize yield and quality in Northeast China.In this paper,85 isolates of E. turcicum were identified physiological races, which collected from the northeastern of China in 2014. On this basis, artificial inoculation was used to infect varieties of Liaoning Province to study the varieties resistant to northen corn leaf blight; SSR (Simple Sequence Repeats) molecular markers was used to marker Ht gene of maize of Liaoning province. The results were as follows:1.85 isolates of Exserohulum turcium which collected from northeastern China in 2014, was identified on different races, and its race dynamics was investigated. Conventional host identification method was used.The result shows that 10 physiological races were identified. including 0、1、2、3、N、12、1N、2N、12N and 23N. Among these races population, races 2 was predominant which accounting for 40.18% of total strains. The 85 identified Exserohulum turcium, virulence to Htl, Ht2, Ht3 and HtN resistance genes 16.48%,50.60%, 2.36%,23.53%, respectively. The results showed that physiological various types in different provinces of the Northeast and composition were quite different. Overall, the Exserohulum turcium range of various species, differentiate more obviously. Great changes have taken place in the types and composition of Exserohulum turcium.2. Ht resistance gene of 66 maize varieties of Liaoning Province were markered, using the SSR (Simple Sequence Repeats) molecular marker method. The results showed that Dika 516, Danyu 508, Danyu 303, Danyu 368, Danyu 801, Danyu 402, Danyu 304, Danyu 210, Xianyu 335, Jixiang One, lianda 99, Huadan 38, Tung Yu 33, the Xianyu696, Jidon 21 Shengdan 306, Enxiai289, Tie 388, Tie 390, Denhai 176, Shen137, the 21 varieties produce bands which consistented with Htl gene, accounting for 31.82% of the total material; Haihe 78, Danyu 307, Danyu402, Jinzhong68, Xiyuan29, Jinyuan 007,the 6 varieties produce bands which consistented with Ht2 gene accounting for 9.10% of the total material.3. Artificial inoculation method was adopted to identify the natural disease resistance on the 84 maize varieties of Liaoning Province. The results showed that 62 varieties are resistance (resistance, moderate resistance and high resistance), accounting for 73.81% of the total material; 22 varieties are susceptibility (sensitive, high sensitive), accounting for 26.19% of the total material. Disease-resistant materials mainly in resistance and moderate resistance, high resistance percentage less; Infected material was given priority to infected materials, high sensitive occupied less proportion.4. Selected 0,1,2, N and 23N physiological races to infect the 74 main variety of Liaoning province to identify the different physiological races of virulence. The method of isolation of spray was adopted. Identification results showed that the 23N race virulence was the strongest; races 2 and 1 were second; races 0 and N of the virulence were weaker.59% of the varieties resistent to two or three physiological races; 3% of all varieties resistent to five physiological races.