HARVESTING OF SEED COCOONS ON DIFFERENT HOURS OF PUPATION AND ITS EFFECT ON COCOON AND GRANAGE PARAMETERS IN SILKWORM BOMBYX MORI L.

The effect of harvesting of seed cocoons on different hours of pupation in one multivoltine breed (BL 67) and two bivoltine breeds (CSR2 & CSR4) and its effect on cocoon and grainage parameters was tested. In BL67, the cocoons were harvested on 42-45, 66-69, 90-93, 114-117, 138-141 hours (control) after mounting and in CSR2 & CSR4, the cocoons were harvested on 6669,90-93, 114-117, 138-141, 162-165 hours (control) after mounting. Different day's harvested cocoons were kept horizontally in a single layer in trays. On 6-7" day the cocoons were assessed for cocoon characters. Later, the cocoons were processed for silkworm seed production. The data revealed that in both the races, melting %, percentage of tail shrunken pupa was reduced significantly and percentage of normal pupa, egg recovery percentage and fecundity was significantly increased in early harvested batches when compared to control. In addition, sex separation was easier in early harvested batches. Hence, the present observation concludes that harvesting of mulivoltine seed cocoons between 42-45 hrs and bivoltine cocoons between 60-72 hrs after mounting and preserving them in a single layer in horizontal position improves the % of clear pupal sexual marking, egg recovery, fecundity and reduction in melting percentage. Further, it also helps in easy sex separation.