Textile Properties for the Cocoons Fabricated by Non-Genetically Modified Bombyx mori Silkworms

抄録

Naturally cocooning of Bombyx mori silkworms was analyzed applying the allometric scaling method to the statistics data on the non-genetically modified Bombyx mori silkworms of 188 breeds including G₀,F₁,F₁× G₀,andF₂, and discussions were made from the viewpoint of the body size effect on the tensile properties,fineness of raw silk threads. The strategically controlled line-breeding effectively cured the unfavorable spinning habits of silkworms and could bring about the production of cocoons fabricated by a longer filament with a higher reelability. The positive body size effect on the fineness of raw silk threads was confirmed. However, the tensile strengths of raw silk threads concentrated around 4 gf/d and were almost independent of the body size of silkworms. The raw silk threads of cocoons obtained in September and/or October showed slightly lower tensile elongation at break compared with June. However, no significance was recognized under the condition of P<0.05. It was thought that the excess intake of metallic compounds by silkworms through digesting mulberry leaves is not likely to affect the tensile properties of cocoon threads.