In Korea, the wide hybridization program started in the mid-1980 at National Institute of Crop Science with objectives of transferring resistance/tolerance to biotic and abiotic stresses and increased yield potential from AA and other genomes of wild species into japonica cultivars. Until now, interspecific hybrids and back-cross progenies were produced from crosses with 11 wild rices involving genomes of AA, BBCC, CC, CCDD and EE. The most difficult step in wide hybridization was to make the early backcross progenies from BC1 to BC3 due to the extreme grain shattering and low seed setting. Two techniques, ovule culture technique and hormone treatment, have proved quite useful for obtaining backcross plants. We have focused on producing the advanced backcross introgression lines from crosses with O. minuta(BBCC), O. glaberrima(AA) and O. rufipogon(AA). The three promising lines in replicated yield trial derived from Hwaseongbyeo x O. minuta (BBCC) were resistant to black streak dwarf virus, bacterial blight and blast. These lines were designated as Suweon 487, Suweon 497 and Suweon 506, respectively, and tested for local adaptability in Korea. Transgressive variations were observed for yield and yield-related traits in introgression populations derived from the crosses with AA, BBCC wild rices. SSR and AFLP markers successfully detected the trait-improving alleles for yield and yield components in the introgression lines from crosses with O. minuta, O. rufipogon and O. glaberrima. These results suggest that these wide-cross progenies could be utilized to broaden rice gene pool for japonica rice improvement.