GENE PYRAMIDING THROUGH INTERCROSS POPULATIONS FOR BACTERIAL BLIGHT AND BROWN PLANTHOPPER RESISTANCE IN RICE.

Conventional breeding approaches often rely on bi-parental crosses, in which analysis occurs only on two alleles, and genetic recombination in such a population is insufficient, limiting genetic diversity. Multi-parent advanced generation inter-cross (MAGIC) populations display large sets of recombinant inbred lines (RILs) that exhibit a genetic mosaic of multiple founder parents. MAGIC populations result in a broader genetic base that has emerged as a powerful tool for genetic analysis and breeding for disease resistance in rice. This study developed the MAGIC population by intermating eight diverse founder parents. Conducting the molecular survey sought to analyze the genes resistant to bacterial blight (BB) and brown planthopper (BPH). The research used primers specific for Xa21, xa13, Xa4, and Bph1 in the polymerase chain reaction (PCR). The survey identified combinations of three genes: (Xa4+xa13+Xa21) in BR52 and (Xa4+xa13+Bph1) in BR43, BR44, BR48, and BR58. Two-gene combination (xa13 and Xa4) materialized in BR53, BR54, BR60, BR73, BR85, and BR86, while identifying a combination of xa13 and Bph1 in BR11, BR41, and BR99. Xa4 was present in 14, xa13 in six, and Bph1 in three lines. Screening the population against Xanthomonas oryzae validated the presence of BB-resistant genes. The consistent finding is that the RILs with a combination of two or more genes express a high level of resistance compared with the RILs with a single gene. The RILs with Xa4 and xa13 expressed more resistance than the lines with xa13 and Bph1. Employing the MAGIC populations approach remains to be effective for gene pyramiding. [ABSTRACT FROM AUTHOR]