| Bacterial grain blight of rice(BGBR),also known as bacterial panicle blight of rice(BPBR),is a typical seed borne disease caused by two pathogens,Burkholderia glumae and Burkholderia gladiolus.At present,the occurrence of this disease is becoming more and more serious,and it has gradually become one of the important rice diseases in China,which has seriously affected the production of rice in China.In recent years,rice planting areas in Jilin Province which is dominated by japonica rice have found that after rice heading,a large number of brown disease spots appear on the glume and gradually spread.The obvious boundary line between the diseased and healthy junctions,and the serious whole grain were dark brown,even deformed and not bearing.The occurrence of this disease is more similar to Bacterial grain blight of rice described by southern scholars.In order to confirm the occurrence of the disease in Jilin Province,this study collecting specimens in main rice growing regions of Jilin Province.Classify the symptoms and isolate and identify the pathogenic bacteria.This experiment was based on the analysis of colony morphology,physiology and biochemistry,16S-23 Sr DNA sequence alignments and so on to determine the taxonomic position of the pathogen of this disease.Two representative strain C17 and C23 with most toxic were used to interact with the resistance of 144 rice varieties planted in the three northeastern provinces,and bactericide’s response test.To screen out resistant varieties and the effective bactericide.Results are as follows:(1)In this experiment,193 samples collected from Chagan,Ganzhou,Anguang,Taonan,Yongji and other counties and cities,Jilin Province were used to describe symptoms and isolate and identify pathogens.The results shows: The symptoms of bacterial grain blight of rice in jilin province were divided into three types.First,a few brown spots have just appeared on the grain,the grain is still full;Second,half of the grains were generally brown in health,the border between disease and health is obvious,the whole was dark brown,and the grains were withered and not strong;Third,the grains are greenish and pale color,and there was a clear brown dividing line at the junction between the disease and the health.Among them,no pathogenic pathogen were found in symptom 1,and the separation rates of symptom 2 and symptom 3 were 13.02 % and 63.16 %,the proportion of pathogen was 32.7 % and67.3 %.According to the results of identification,B.glumae and B.gladioli were the pathogens causing bacterial grain blight of rice in jilin province.(2)The two pathogenic bacteria with the most toxic were isolated,B.glumae(C17)and B.gladioli(C23)were used to analyze the resistance of 144 rice varieties in the three northeastern provinces.The results shows: There was little difference in the resistance of all tested varieties to the two pathogens,it indicates that the pathogenicity effect of the two pathogens is similar.Among the 144 kinds of rice varieties,there were 10 resistant varieties including Jiudao 44 and Jiudao68,4susceptible varieties,1 susceptible variety,and no high resistant varieties were found.And the resistant types to both pathogens were mainly medium resistant variety,followed by medial susceptible variety.(3)By using the method of bacteriostatic circle,9 kinds of bactericide that have obvious inhibitory effect on both pathogens were screened out from 24 kinds of bactericide by toxicity measurement.According to the indoor results and field experiments,six effective bactericide were obtained,one of the Ambam 45 % AS that effective control has reached over 80%,it can be used as the first choice for control bacterial grain blight of rice.The control effect of Copper succinate glutarate adipate30 % SC,Cuppricnonylphenolsul 30 % ME,Copper oxychloride 30 % SC,Chlorobromoisocyanuric acid 50 % SP,Kasugamycin 2 % AS was over 70 %,which can be used as a standby agent. |
