Identification Of Phytophthora Capsici On Chili (Capsicum Annuum) And Screening Resistant Germplasm

Chili Phytophthora blight, which caused by Phytophthora capsici that belongs to Mastigomycotina Oomycetes Peronosporales Phytophthora, was fungal soilborn disease and happened frequently in open and protected fields. The races of Phytophthora capsici were diversity. The disease had a wide geographical distribution, and developed rapidly, caused serious reduction in chili production. The research of the pathogen and disease-resistance breeding was necessary and effective method to control the disease.Experiment contents :1. The isolation and identification of pathogens. 2. Biological characteristics of the pathogene. 3. Screening the method for chili resistance identification to Phytophthora capsici at seedling stage. 4. Races identification from different regions. 5. Screening resistant germplasm.Conclusion:1. 28.9% isolates was Phytophthora capsici through the isolation, purification and identification of pathogens from Liaoning, Jilin, Heilongjiang.2. The culture medium for the growth of the pathogen were oats culture medium and corn flour medium; PSA culture medium was suitable for sporagia producing; the best preservation medium was PSA medium; 28℃was the most appropriate temperature for the growth of the pathogen, and 30℃was the suitable temperature for sporagia producing; the optimal pH was 7 for the growth of the pathogen and sporagia producing; 24h illumination was the best for sporagia producing, the quantity of zoospore was the largest after six days full- illumination , .3. The identification of the chili resistance to Phytophthora capsici at seeding stage was studied by the method of replicated orthogonal design.The optical combination of identification of chili resisrance to Phytophthora capsici was immersing-rooting inoculation method at 7-leaf stage and 2X104 per milliliter inoculation concentration.4. Identification of pathogens from Liaoning, Jilin, Heilongjiang, there was three race,which is Race1,Race2,Race3, race3 which accounted for 47.4%,Race1 and Race2 were the same proportion ,was 26.3%. Race 3 was the dominant race in northeastern China.The race was Race 1 in Dandong, Dalian, Yuhong district, Beipiao and Faku, Shenyang; race from Shenyang Academy of Agricultural Sciences was Race 1 and Race 2; the race of Gongzhuling and Siping was Race 3; the race was Race 1 and Race 2 from Mudanjiang; Jiamusi was Race 2; the l race in Zhaodong and Daqing was Race 1; the race of Harbin was Race 3.5. 51 chili varieties from the Harbin Academy of Agricultural Sciences were inoculated by the above combination.The results of screening disease-resistant chili were that there was one high-resistant variety; 10 resistant varieties; 19 medium-resisitant varieties; 21 the susceptible varieties.