Pyramiding Pita, Pigm, Pi2, and Xa23 to Develop Hybrid Rice with Dual Resistance to Rice Blast and Bacterial Blight

Rice blast and bacterial blight cause severe harm to rice production, and the breeding of resistant varieties guarantees the safety of rice production. Meanwhile, multigene pyramiding breeding based on molecular marker-assisted selection is a crucial approach for rice breeding to combat multiple diseases. This study aimed to develop accurate and efficient PARMS markers for rice blast resistance genes <i>Pita</i>, <i>Pigm</i>, and <i>Pi2</i>, and bacterial blight resistance gene <i>Xa23</i>. A systematic genotyping analysis of the resistant alleles of these 4 genes was performed on 384 major cultivated varieties in production. The results showed that only 5.21% of the varieties harbored more than two resistant alleles simultaneously. Using traditional breeding strategies in combination with the developed PARMS markers, the high-quality three-line male sterile line Ruanfeng A (pyramiding <i>Pita</i> and <i>Pigm</i>) and the strong restorer line Gui 610 (pyramiding <i>Pi2</i> and <i>Xa23</i>) were bred. Crossing these lines produced a new hybrid rice variety, Ruanfengyou 610. Ruanfengyou 610 pyramids 4 resistance genes (<i>Pita</i>/<i>Pigm</i>/<i>Pi2</i>/<i>Xa23</i>), exhibits resistance to both rice blast and bacterial blight, has prominent heterosis and excellent grain quality, and has strong application potential, which is of great significance for ensuring the safety of rice production.