The breeding work was initiated by utilizing two Japanese hybrids namely C135${ imes}$N134 and N137${ imes}$C146 along with two evolved Indian breeds, J14 and A24. The breed CSR16 which is characterized with marked larvae and white dumbbell cocoons was evolved from the Japanese hybrid C135${ imes}$N134 by crossing with J14, while the breed CSR17 which is characterized with plain larvae and white oval cocoons was evolved from the Japanese hybrid N137${ imes}$C146 by crossing with A24. The hybrid of these evolved breeds i.e., CSR16${ imes}$CSR17 has shown superior over control hybrid $KA{ imes}{NB_4}{D_2}$ and on par with the ruling hybrid of CSR2${ imes}$CSR4. The hybrid CSR16${ imes}$CSR17 was authorized during 1999 by Central Silk Board, Bangalore, Government of India for commercial exploitation during favourable months based on national level race authorization test.