Resistance Evaluation Of Primary Core Collection Of Chinese Rice Germplasm To Rice Blast And Bacterial Leaf Blight

Rice blast (Magnaporthe grisea Barr., Pyricularia oryzae Cav.) and bacterial leaf blight (Xanthomonas oryzae pv. oryzae) are major devastating diseases in rice, which not only cause great losses in rice production, but also decrease rice quality. Resistant variety breeding remains the most economic and effective approach for controlling rice blast and bacteria leaf blight. Exploitation and utilization of rice germplasm resources with high resistance, high yield and qulity are still the most important jobs. Therefore, resistance of the primary core collection of Chinese rice germplasm (including 203 accessions) to rice blast and bacterial leaf blight were evaluated. Results were summarized as follows:1. Among the 203 rice accessions, 41.38% and 78.82% were resistant to leaf blast and panicle blast, respectively. Nineteen varieties (9.45%) and 9 varieties (4.48%) showed resistance to 80%-90% and 70%-80% races of Magnaporthe grisea (Hebert) Barr, with 66.50% of the tested varieties resistant to 20%-70% races of the pathogen. According to the results of correlation analysis, resistance spectrum of the varieties in seedling stage was significantly correlated with leaf blast resistance at the 0.01 probability level( r= -0.3624, P < 0.0001 ) but not with panicle blast resistance. Leaf blast resistance was aslo not significantly correlated with panicle blast resistance. According to the results of clustering analysis, japonica rice varieties from the primary core collection could be classified into seven groups. Fifteen varieties including Xugunuo, fallen into group 3 were resistant to the races of C, D, E and F with resistance spectrums from 68.8% to 87.5%. For indica rice, twenty-six varieties belonging to group five (six groups in total) were resistant to races of E, F and G with resistance spectrums from 50.0% to 87.5%.2. There were two (0.98%) and six (2.98%) varieties resistant to 75% and 62.5% of the strains of Xanthomonas oryzae pv. oryzae. One hundred and eighty-eight varieties(92.61%) showed resistance to less than 50% of the tested strains of X. oryzae pv. oryzae. According to the results of clustering analysis, japonica rice from the primary core collection could be classified into seven groups. Twelve varieties including Tieganwu, fallen into group 3 resisted strains of OS 198 and JS 49-6 with resistance spectrums from 25.0%-62.5%. For indica rice, elven varieties belonging to group four (four groups in total) were resistant to strain OS 198 with resistance spectrums from 12.5%-62.5%.3. Among the varieties, Teqingxuanhui and Huangsigui were high resistance to both M. grisea (Hebert)Barr and X. oryzae pv.oryzae, and Jinxibai, was highly resistant to bacterial strain of POX99.