Isolation of a mutant line with shorter larval duration by induction of mutations in the silkworm Bombyx mori L

Induction of mutations by X-rays in the pure Mysore race of the silkworm, B. mori, has resulted in the isolation of a mutant line exhibiting a much shorter larval duration than the control. The 8th day eggs and 3rd instar larvae were exposed to variable doses of X-rays of 1000 and 2000 R respectively. The 8th day eggs were found to be more sensitive for irradiation. The mutant line isolated from the progenies of the irradiated eggs exhibits a relatively faster rate of development. In addition, the mutant line exhibits certain degree of improvement in the commercial characters such as cocoon weight, shell weight percentage of silk, etc. over those of controls. The significance of faster rate of development and improvement in the commercial characters of the mutant line are discussed in relation to economics of sericulture industry. (author)