Marker-Assisted Backcrossing For Introgression of Broad-Spectrum Bacterial Leaf Blight Resistance In MR297 Malaysian Elite Variety

Abstract

One of the most critical aspects of marker-assisted backcross breeding is recurrent parent genome recovery (RPGR). RPGR ensures that only the genes of interest are retained without further segregation in the recombined progenies while the unwanted genomic segments are completely deleted. This experiment aimed to introgress multiple bacterial leaf blight (BLB) resistance genes against using marker-assisted backcross breeding. Four Xoo resistance genes viz: Xa21, xa13, xa5, and Xa4 from IRBB60 were introgressed into the genetic background of MR297 Malaysian, which is considered a high yield. Polymorphic functional linked markers to target genes and SSR markers were used for both foreground and background selection. The percentage of RPGR in the selected lines, a background selection was adopted using 83 approved polymorphic microsatellites markers. The study results reveal RPGR of 81.94%, 92.30%, and 95.32% at BC1F1, BC2F1, and BC2F2, respectively. Marker-assisted backcross breeding often shows a faster introgression resistance gene than traditional breeding. The introgression of four BLB resistance genes Xa21, xa13, xa5, and Xa4 in the nine newly developed lines would provide durable and broad-spectrum resistance against the bacterial leaf blight. The newly created lines were suggested for commercial production as new rice varieties.