Identification Of Resistance To Baeterial Leaf Blight And Detection Of Resistance Genes Xa-5 In Seventy-nine Commercial Rice Cultivars(Lines)

Rice bacterial leaf blight caused by Xanthomonas oryzae pv.oyzae(Xoo)is one of the most devastating bacterial diseases worldwide.By identifying the resistance of rice varieties to bacterial leaf blight and detecting resistance genes,it is very helpful to provide the information for breeders and agricultural extension organization and to effectively controll this disease by planting resistant varieties.This paper focused on the identification of resistance levels of seventy-nine rice varieties which are collected from Jilin?Yunnan?Zhejiang?Hunan?Jiangsu and Guangdong provinces with 9 races of Chinese bacterial blight and also detection of resistance gene xa among these varieties.The main results could be summarized as follow:1?It was evaluated that resistance levels of seventy-nine rice varieties which are collected from Jilin?Yunnan?Zhejiang?Hunan?Jiangsu and Guangdong provinces to the nine races YN18?YN1?GD414?HEN11?ScYc-b?YN7?YN11?FuJ and YN24 of bacterial leaf blight in 2013 and 2014.The results showed that the resistance of varieties collected from Jilin?Yunnan and Hunan provinces to bacterial leaf blight was relatively weaker,and there were several resistant sources resistance to 5 races in Jilin?3 races in Yunnan and 6 races in Hunan.That indicated that these provinces probably need to improve their regional distribution of rice varieties,and breed some new varieties with stronger resistance in the future breeding and agricultural production.Those varieties from Guangdong and Jiangsu provinces were resistant to 9 races,and varieties from Zhejiang province were resistant to 7 races.The results indicated that there was a relative rational situation in varieties distribution for these three provinces.Highly pathogenic races FuJ and YN24 could infect more than 90%of the varieties tested with susceptible or moderately susceptible symptom,and the race YN18 with weaker virulence only infected Yunjing 41 and Longyang 1.As the previous report race YN1 became more virulence based on its pathogenic pattern.which could infected 73 varieties tested.2?It was designed the dCAPS markers for the sequence difference between cloned resistance gene xa5 and its allele,and detected whether there was a resistance gene xa5 in 79 materials with restriction endonuclease Hpy178?.The results show that only genomic amplification products of IRBB5 positive control contained xa5,and other genome amplification product of other 79 cultivars and negative control IR24 were digested to two fragments with 180 bp and 220 bp,which indicated that there was no xa5 in 79 varieties.