| Bacterial blight (BB), caused by Xanthomonas oryzae pv. oryzae (Xoo), is one of the most devastating diseases of rice world-wide. Rice bacterial blight isolates is various, and the toxic change so fast that variety is easy to lose the resistance to isolates. Molecular breeding has been advocated as a highly efficient breeding method, because it can offer rapid and precise selection of the targeted gene. This study was conducted in a number of rice varieties inoculated based on different isolates of bacterial blight. Then, study rice varieties resistant spectrum, and the interaction between rice varieties and isolates of bacterial blight. The main study and results are as follows:1. White rice bacterial leaf blight disease in different races of Resistance:The results show 39 of 68 varieties of early rice was resistant to more than five strains isolates tests; 104 of 138 varieties of medium rice was resistant to more than five strains isolates tests and 38 of 51 varieties of late rice was resistant to more than five strains isolates tests. There have 8 varieties which resistant to all isolates tests,12 varieties which resistant to 8 isolates tests,21 varieties which resistant to 7 isolates tests,53 varieties which resistant to 6 isolates tests,73 varieties which resistant to 5 isolates tests.2. The resistant reaction between the characteristic rice cultivars to Xanthomonas oryzae pv.oryzae different virulent strains:we inoculated and co-inoculated 7 rice cultivars with 9 different virulent isolates in this research. The inoculation result shows that there was a significant difference in the symptoms of a rice cultivar by the two distinct inoculations. The concrete details of this result:there exists a significant difference in the virulence of a single inoculum and mixed inoculum, and the difference could be expressed through the interactions between strains and cultivars. Because of the mixture with different virulent strains, there exists reciprocal inhibition between these strains in some way. The intensity of inhibition was related to strains we selected as components of the mixed inoculum and the pathogenicity was closely related with its virulent structure.Verified by laboratory experiments show mixing isolates WH7 and YC20 can significantly decrease pathogenicity, so its function can control bacterial blight development.3. Technical measures to prevent and control bacterial blight of different effect: impact of blight affecting the species occurs are the major factor, the same species, bacterial leaf blight disease index increased with the amount of applied N increased, several factors affect the effect size of the bacterial blight order:Variety> Nitrogen> Variety×Nitrogen; The time of water-logging can increase length of lesion and different varieties have significantly effect on it. Even under ten hour water-logging, bacterial blight index of high-resistance varieties is lower than of susceptible varieties. So selecting high-resistance varieties is the mainly way to control bacterial blight. So choosing high-resistance varieties, precise agronomic practice and chemicals spray is important to control bacterial blight development and reduce yield loss for bacterial blight. |
