Abstract:The genetic diversity of blast rice resistance of the rice commercial and local resource cultivars in Jiangxi Province were studied using resistance gene analogue (RGA) based on resistance gene conserved sequences. The RGA analysis for 23 cultivars was proceeded by the PCR amplification using the primers XLRR for/ XLRR rev designed based on the resistance gene Xa21 for Xanthomonas oryzae pv. oryzae. The results showed that rice cultivars were genetically highly diverse. All the cultivars were divided into 6 lineages according to the DNA band data at the lineage distance of 4.5, and divided into 2 lineages at the lineage distance of 5. Field experiments of mixed- and pure-planting of four rice varieties, representing hybrid varieties (Shanyou 63 and Liangyoupeijiu) and traditional high-quality varieties (Landounuo and Yuanlinuo), were conducted based on the differences in their genetic backgrounds. The mixed-planting of the hybrid rice and traditional high-quality rice varieties had a significant effect on the occurrence of the rice blast, particularly for the highly susceptible traditional varieties, with significant decrease in incidence and disease index and 91.98%-95.68% of control efficiency. This suggests that appropriate mixed-planting of rice varieties with different genetic backgrounds is an effective approach for rice blast control.