A RAPD marker identified a susceptible specific locus for gall midge resistance gene in rice cultivar ARC5984

Gall Midge (Orseolia oryzae) is one of the serious insect pests of rice in Asia and South East Asia. In India, gall midge has been a particular problem because of the presence of five different biotypes in different geological regions. The annual yield losses due to gall midge have estimated to be in a range of 28-35%. The present study covers phenotyping of recombinant inbred lines (RILs) for gall midge resistance/susceptibility, bulked segregant analysis (BSA) to identify putative marker(s) and individual analysis to confirm linkage between putative marker(s) and gene-controlling gall midge resistance/susceptibility. Phenotyping of 120 RILs-F9 derived from a cross between ARC5984, Resistant parent and Taichung Native1 (TN1), susceptible parent were screened against gall midge biotype 2. A total of 58 lines showed resistance, 56 lines were susceptible while only 6 showed segregation. Genomic DNA of 30 homozygous RILs (15 homozygous resistant and 15 homozygous susceptible) were taken for BSA with 33 random oligonucleotide primers by RAPD marker analysis and successfully amplified a total of 256 loci. Out of which only one primer i.e. OPQ05 has shown polymorphism in 1150 bp locus in susceptible parent and susceptible bulk. The OPQ051150 used for co-segregation analysis for those 30 RILs individually out of which 9 were recombinant. The marker OPQ051150 was found to be linked to the susceptible specific gene at the distance of 30 cM.