Improvement of Dubraj and Safri-17 varieties for conferring resistance against bacterial leaf blight through marker assisted selection approach

Abstract

Marker assisted selection was employed to pyramid three bacterial blight resistance genes Xa21, xa13 and xa5 into high yielding susceptible local varieties Dubraj and Safri-17. Homozygous and heterozygous genotypes were identified in Dubraj X RP-Bio-226 and Safri17 X RP-Bio-226 crosses with the help of PCR markers and goodness of fit was tested. We tried to introgress multiple resistance genes responsible for BLB resistance (xa5, xa13, Xa21) in local variety Dubraj and Safri17. Dubraj is local scented variety while Safri 17 is high yielding variety of Chhattisgarh. Both the varieties have premium cooking quality. We screened the host plants for resistance against BLB by inoculating the leaf with the strain of Xanthomonas oryzae at Raipur (Chhattisgarh) through clip inoculation method. Genotyping with SSR primers was done to select lines introgressed with multiple resistance genes for BLB as well as blast. Populations introgressed with resistance genes for both BLB and blast, including 20 lines of Dubraj, 15 lines of Safri17 in F3 generation, 8 and 22 lines of Dubraj and Safri in F5 generation respectively and 45 lines of Dubraj and 60 lines of Safri 17 in F6 generation were selected on the basis of genotyping and phenotyping. Genotypes carrying resistance genes in different combinations were identified, selected lines were backcrossed with susceptible parents and generation advancement was done for others. The pyramided lines showed a wider spectrum and higher level of resistance against Xoo isolates under field conditions.