Abstract:

This study aims to improve the bacterial blight resistance of photo-thermo-sensitive genic male sterile ‘Quan 211S’ with high quality. Using ‘Quan 211S’ as the recipient parent and ‘CBB23’ containing Xa23 gene as the donor parent, the sterile lines resistant to bacterial blight were bred by combining molecular marker-assisted selection technology with conventional breeding technology. Four improved sterile lines, from Qk211s-1 to Qk211s-4 were selected. The agronomic characters, fertility alteration temperature and outcrossing setting rate of the improved lines of ‘Quan 211S’ were similar to those of ‘Quan 211S’, but the resistance to bacterial blight was significantly enhanced, showing high resistance or resistance, and the resistance level was 0-2. The combinations of improved lines of ‘Quan 211S’ had no significant differences in plant height, grain number per panicle, seed setting rate and 1000-grain weight compared with those of the combinations of ‘Quan 211S’, but the resistance to bacterial blight was significantly enhanced, showing high resistance, and the resistance level was 1. The four improved lines of ‘Quan 211S’ can lay a foundation for breeding disease resistant rice varieties and be directly applied in production.

Key words: rice, molecular marker-assisted selection, bacterial blight, Xa23 gene, dual-purpose genic sterile line