Genetic variability analysis of some bivoltine silkworm (Bombyx mori L.) breeds

Abstract

Nineteen bivoltine silkworm breeds of varied eco-geographical origin were analysed for genetic variability for eleven economic traits. The study revealed significant differences among the breeds in traits studied. On the basis of clustering, breeds could be grouped into seven clusters and the number of breeds in different clusters varied. Cluster 1st comprised maximum (five) breeds and the cluster 7th had only one breed. Breeds spinning oval and constricted cocoons fell in the same cluster which clearly showed that breeds exhibiting phenotypic divergence may not be genetically diverse. The clustering pattern also depicted a mixed trend, silkworm breeds having different geographic origin were included in the same cluster and breeds having same geographic origin fell in different clusters this revealed that geographic and genetic diversity have no association. Crossing of breeds from most distant clusters may yield heterotic crosses and transgressive segregants in advanced generations.