Establishing a durable, widely-applicable blast resistance strategy for elite indica breeding programs

Rice blast is one of the most destructive diseases affecting rice crops globally. Successful deployment of blast resistance genes needs to be both durable and effective across a wide range of targeted regions. By employing gene stacking or pyramiding, the robustness in resistance of rice cultivars is amplified, ensuring long-term and sustainable protection against the disease. The Native Trait Discovery and Deployment team at IRRI has completed introgression of major blast resistance genes, including Pi9, Pi35, Pi54, Pikh, and pi21, into elite IRRI 154 background. Effectiveness of these genes were validated through the collaborative screening efforts conducted by IRRI BioNet and partner institutions at multiple locations, including the Philippines, Bangladesh, and India. Ongoing augmentation activities are focused on the blast pyramid, Pi9+Pi35+Pi54-Pikh+fgr+Hd9N22, for 64 elite recipient lines from IRRI and AfricaRice breeding programs. Large-scale backcrossing of the target loci is carried out into these recipients, thereby rapidly increasing the frequency of high-value genes in elite breeding programs.