Factor Analysis on the Parthenogenetic Development of Ovarian Eggs in the Silkworm, Bombyx mori L. : Lepidoptera

Factor analysis was performed on the parthenogenesis of silkworm ovarian eggs. The method of ASTAUROV (1967) was used for the induction of parthenogenesis and experiments designed for factor analysis were performed according to the formulae of MATHER. The percentage of parthenogenesis of eggs varied widely among tested strains and was generally higher in hybrid strains than in their original races. Heterosis was found in these hybrid strains. When the percentage of parthenogenetic eggs was compared in terms of cross and reciprocal cross F1 generations which had the same genetic structure, a higher percentage of parthenogenesis of eggs was found in hybrid strains with highly parthenogenetic original races. This result indicated that some maternal factors might influence the occurrence of parthenogenesis. Results of the factor analysis revealed that unfixable genetic factor had the highest genetic influence followed by fixable genetic factor and environmental factor.