Marker-assisted introgression of bacterial blight resistance gene xa13 into improved CO43

Biotic stresses cause severe yield reductions in rice and are a threat to global food security. Developing resistant cultivars is the most affordable and sustainable approach to handling different biotic stresses. CO43 is an elite rice variety of Tamil Nadu susceptible to gall midge (GM) and bacterial blight (BB). In this regard, the current research was carried out to pyramid a major BB resistance gene xa13 into the background of the improved CO43 carrying two major genes for GM resistance Gm1 and Gm4 . The improved CO43 was crossed with the donor line B95-1 X Abhaya, carrying the BB resistance gene xa13 and GM resistance gene Gm4 . Marker-assisted backcross breeding was employed to develop three gene-pyramided homozygous BC 3 F 3 lines ( Gm1Gm1 + Gm4Gm4 + xa13xa13 ). Foreground selection was done at every generation using the functional marker xa13-prom for selecting the xa13 gene and the SSR markers RM1328 and RM22550 for targeting the Gm1 and Gm4 genes, respectively. The selected BC 3 F 3 lines were highly resistant to GM and BB. Agronomical and grain quality evaluation of the selected lines led to the identification of two lines, C39-24-11 and C39-24-127 having yield on par with the improved CO43. The selected lines will be further pyramided with additional BB and blast resistance genes to develop improved lines with durable resistance against multiple biotic stresses of rice.