Correlation Studies Among Different Quantitative Traits of Silkworm, Bombyx mori L.

The silkworm, Bombyx mori L., most important source of natural silk has played an important role in the life of man ever since its discovery by the Chinese some 4000 years ago. It is also traditionally associated with the socio-economic life of many countries. Even today it enjoys the supremacy over all other fabrics and it is appropriately called “Queen of Textiles” for its unparallel lustre, delicacy, elasticity, crispness and artistic appearance.

 

According to Krishnaswami et al. (1973), the mulberry silkworm, Bombyx mori L., is the greatest source of natural silk. Generally we have two type of silkworm, viz. mulberry and non-mulberry silkworm. The silkworm larva passes trough five different stages called instars. The final or 5th instars spin to form cocoon within which the larva undergoes pupation. The cocoon shell is the source of the natural silk, which is the driest form of that secretion. Basically there are two proteins which go to form the silk fibre viz., “fibroin” which constitutes the core of the fibre and “sericin” a waxy substance which encases the fibroin.

 

The origin of sericulture, silk production and weaving is ancient and clouded with legend. They are closely interlinked with the emergence of China as one of the great civilizations. Chinese mythology ascribes the invention of this art to the mythical Empress Shih Xiling, the consort of the no less mythical “Yellow Emperor”, Shi Huang Ti, one of the fathers of Chinese civilization. Ancient Chinese annals give an exact date for Empress Xiling’s discovery of silkworm rearing, namely 2640 B.C. It is said that one day 14-year-old queen was enjoying a tea ceremony in her palace garden with her friends and maids under a mulberry tree, suddenly a golden coloured cocoon dropped in her teacup. When she tried to remove the cocoon from the teacup, an end of the filament comes out of the cocoon and it was a continuous one. Then she collected some more cocoons, carried them to her palace, preserved them till emergence and reared in the next generation and later invented the method of reeling (Sarkar, 1958).

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