Genetic analysis of cry1Ab gene in segregating populations of rice

Three transgenic Bt lines (Tarom Molaii, Neda and Nemat), all containing a synthetic cry1Ab gene were crossed with conventional rice varieties. The mode of resistance to striped stem borer (Chilo suppressalis) in these lines was investigated through field studies and PCR analysis of progenies in F sub(2) and BC sub(1) populations. The monogenic segregation of 3:1 and 1:1 were observed in segregating populations of F sub(2) and BC sub(1), respectively, either phenotypically under natural infestation of SSB as well as at molecular level by means of multiplexing PCR analysis using cry1Ab and RG100 primers. These results acquired from phenotypic and genotypic analyses of 1346 and 243 individual plants at field and laboratory conditions imply stable transmission of cry1Ab gene through sexual generations in indica/indica genetic backgrounds. Therefore, rapid development of new elite Bt rice cultivars with sufficient insect resistance and ideal agronomic properties can be achieved through combination of conventional breeding with marker assisted selection.