Photoperiodic Induction of Diapause Character and Sorbitol Level in the Silkworm Eggs of APM1, MU303 and PM Strains/Races

Abstract

Embryonic diapause is the suspended animation responsible for the onset of Voltinism in the silkworm. The embryo is completely arrested during the developmental event to overcome unfavourable environmental conditions. This further results in the synthesis of sorbitol from glucose and examines the differences between sorbitol levels in the diapause-induced silkworm eggs of APM1, MU303 and PM strains by exposure to photoperiodic regime of 16L:08D, 14L:10D and 12L:12D. The results obtained revealed the fact that the sorbitol level is high during the 6th day in all the selected strains at their 7th and 8th generation. This indicates that the enhancement of the sorbitol is independent of the induced diapause in all three strains of the mulberry silkworm. Further, it is also clear that the enhancement of sorbitol concentration is devoid of a photoperiodic regime.