Marker assisted introgression for brown planthopper resistance genes Bph20 and Bph21 in CO43Sub1 variety of rice

BPH is the most destructive pest of rice. Host plant resistance is the most desirable way to control the BPH damage. The single gene resistance is easily broken by the evolution of new BPH biotypes, it can be addressed by the gene pyramiding. In order to improve CO43Sub1 with BPH resistance, the foreground selection was carried out in BC2F2 lines derived from the cross CO43Sub1 and donor IR71033-121-15. In this, 44 plants were homozygous and 13 plants were heterozygous for Bph20. Seven plants were homozygous and 31 plants were found heterozygous for Bph21. Only four plants were found to be homozygous for both the genes. Fifteen lines were selected for the phenotypic screening of BPH resistance. The lines 32-4-34 and 32-4-35 were resistance to BPH and six lines were observed with moderate resistance.