DOI: 10.36347/sajb.2014.v02i01.002

Pages: 11-18

Genotype-environment (G-E) interaction and stability parameters were analyzed for ten each of oval and dumbbell silkworm bivoltine genotypes reared during three different seasons of the year. Quantitative economic traits viz., fecundity, cocoon yield / 10000 larvae by number, cocoon yield / 10000 larvae by weight, cocoon weight, shell weight, cocoon shell percentage, filament length, denier, raw silk percentage, renditta, neatness and boil-off loss were evaluated. The mean sum of squares (MS) for the breeds and environments was highly significant in both oval and dumb-bell breeds in respect of all the traits except for renditta clearly indicating substantial variation among the breeds and seasons. However, the G-E interaction was found to be non-significant for all the traits among oval breeds, while among the dumb-bells, only four traits, namely, yield by number, yield by weight, filament length and neatness showed significant G-E interaction. Two stability parameters, viz., regression coefficient (bi) and deviation from regression (s2di) were analyzed in both oval and dumb-bell breeds, which showed significant differences for most of the traits. Based on values of the two stability parameters for the 12 economic traits and cumulative ranking, CSR2, JPN8 (oval) and CSR16 (dumb-bell) were found to be stable genotypes, while, S5 (oval) and BBE267 (dumb-bell) were the least stable