[Variability of the eggs of the local silkworm (Bombyx mori 1.) according to the capacity for thermal parthenogenesis and heat resistance. Report 3. Causes and characteristics of the variability of egg batches according to heat resistance].

The variability of eggs from different batches was studied by the resistance against the sublethal temperature (48 degrees) at the early stages of embryogenesis. The variability of heat resistance at three developmental stages markedly differing by the organization of the embryo was shown to be, to a great extent, conditioned hereditarily and depend as well on the environmental conditions. On the basis of positive correlation between the heat resistance of eggs from the same parents but at different developmental stages, a conclusion is drawn that the variability of heat resistance of the egg cellular proteins is one of the main causes of the variability of egg batches by heat resistance.