author(s)
N Chandrakanth, SM Moorthy, Kariyappa, KM Ponnuvel, V Sivaprasad

abstract
The aim of this study was to assess the performances of F2 and backcross populations at 36 °C by measuring reeling traits in silkworm. Nistari and Cambodge (thermo tolerant multivoltines), CSR2 (thermo susceptible bivoltine), their F1s, F2s and backcross populations without reciprocal crosses were reared at 25 °C and 36 °C. Data on five reeling traits were collected. All the reeling parameters (except neatness) were significantly (P<0.05) reduced at 36 °C compared to their respective control breeds/hybrids. Backcrosses performed better than the F2 populations at 36 °C. CSR2 x (Nistari x CSR2) was one of the best performers in form of reeling traits and Nistari x (Nistari x CSR2) was most stable breed which demonstrated least percentage reduction in treated over control larvae in raw silk percent, and second lowest percentage reduction in reelability percent, filament length, denier and neatness. Therefore, these crosses are preferred for breeding according to the requirement of silkworm breeder.