Abstract:

Breeding disease-resistant varieties is the most effective approach to control rice diseases and pests. To efficiently assemble new disease-resistant combinations, molecular markers of 17 blast resistance genes and 6 bacterial blight resistance genes were used to detect resistance/susceptibility genes in 23 core rice materials. The blast resistance gene detection revealed that high-frequency resistance genes Pid2, Pi40 and Ptr were detected in 23, 15 and 23 materials respectively. Moderate-frequency genes Pi64, Pib, Pi2, Pigm, Pi5, Pi1 and Pikm occurred in 10, 10, 11, 10, 8, 10 and 8 materials respectively. Low-frequency genes Pit, Pi36, Pikh, Pia and Pita were only found in 2, 1, 3, 1 and 1 material. Piz and Pi25 were undetected. Conversely, susceptibility genes pi2, piz, pi25, pikh, pikm, pia and pita showed high frequencies (23, 23, 23, 15, 15, 22 and 22 materials respectively), while pi64, pigm, pi36 and pi5 exhibited moderate frequencies (9, 13, 13 and 13 materials). For bacterial blight genes, only resistance gene Xa27 was detected in 5 materials, while resistance genes xa5, Xa7, xa13, Xa21 and Xa23 were undetected. Susceptibility genes Xa5, xa7, Xa13, xa21, xa23 and xa27 showed high frequencies (23, 22, 23, 23, 23 and 14 materials respectively). This study systematically mapped the distribution of 23 reported resistance/susceptibility genes against rice blast and bacterial blight in 23 rice materials using molecular markers, providing valuable genetic references for subsequent screening, improvement and combination testing of rice germplasm.

Key words: rice, rice blast, bacterial blight, gene, molecular maker