Rearing Performance of Some Popular Bivoltine Silkworm (Bombyx mori L.) Breeds during Spring Season

Twelve popular bivoltine silkworm (Bombyx mori L.) breeds viz., CSR2, NB4D2, SK-1, CSR4, DUN6, SH6, SK-6, CSR19, SK-28, DUN22 and SK-31, were evaluated for their performance during spring 2012 and 2013. The data generated in respect of different traits during two years was recorded replication wise and pooled. The pooled data was analyzed statistically and subjected to multiple trait evaluation index using Mono’s evaluation index method. Analysis of variance showed significant differences among the breeds for all the characters studied. The breeds were ranked as per the cumulative score and the value of a particular trait in a particular breed was compared with the ranking. Six breeds viz., NB4D2, SK-1, SH6, SK-6, SK-28 and SK-31 were short-listed. These breeds s scored higher E I values (>50) and can be used for the preparation of season specific hybrids to push up bivoltine silk productivity under specified environmental conditions in the valley.