Triple ring theory of diapause in silkworm, Bombyx mori

Rajendra Mundkur^a*, Mallesha Murthy^a & Krishna Rao, S^a.
^a*Karnataka State Sericulture Research and Development Institute,
Silkworm Breeding Unit, Bidadi-562109, Ramanagara District, Karnataka, India.

Received  5th Feb., 2012; Revised  2nd June., 2012

Abstract : Discovery of paternal genes taking over the developmental process of diapause-destined silkworm eggs Mundkur et al., (2004)8, has added new dimension to the existing theories of  diapause phenomenon in silkworm,  Bombyx mori. Toyama (1906)¹⁴ defined embryonic diapause in silkworm, Bombyx mori as ‘a maternally inherited biological event under the control of sex-linked genes’. Sonobe and  Odake (1986)¹² have  proposed  two theories related to the diapause: (i) diapause is the phenomenon predetermined by the diapause factor during embryogenesis, and (ii) diapause is the process determined by the genetic factor during embryogenesis. The present authors propose a new triple ring theory related to diapause viz., “diapause is the phenomenon determined by environment, maternal genes and paternal genes synergistically or exclusively”.