Mulberry forms the basic food material for silk worms and the bulk of the silk goods produced in the world are from mulberry silkworms. Sericulture involves agriculture, art and industry; mulberry cultivation involves various farming practices; silkworm rearing is an art in the hands of rural people; reeling of silk from the cocoons formed by the worms is an industry of different financial investments. Scientific sericulture is the meeting place for agriculture and art, art and industry, ancient culture and civilization, the rich and the poor and it reflects the interdependence of these.
Production of mulberry leaves on scientific lines is essential for organizing sericulture on sound economic lines. It is estimated that one metric ton of mulberry leaves is necessary for the rearing of silkworms emerging from out of one ounce of eggs, which will yield about 25 to 30 kg of cocoons of international standard. The cost of leaves works out to about 60 percent of the total cost of production of silk. The bulk of the leaves is required at the final stage of growth of the silkworm .One hectare of fertile land can produce about 15 to 40 tons of mulberry leaves over a twelve month period. This, however, depends on the favourable climatic condition prevailing in the region; in the temperate and subtropical regions of Europe and Japan, about 15 to 20 tons of leaves per ha is produced in a year whereas in the tropical parts of India, under intensive cultivation practices, about 30 tons per ha could be harvested in a year. While mulberry leaf is available for rearing in Japan, the Republic of Korea and the U.S.S.R. for two to three rearing seasons a year, in the tropical countries like India, the leaves are harvested and utilized for silkworm rearing throughout the year.
Morus is the Latin word of mulberry (French: muries, Italian: gelso, Japanese: lewwa). Mulberry plant is exploited in different ways for commercial production of silk, as mulberry is the chief food for Bombyx mori. Mulberry leaf protein is the source for the silkworm to bio-synthesize the silk which is made up of two proteins, fibroin and sericin. Nearly 70 percent of the silk proteins produced by a silkworm is directly derived from the proteins of the mulberry leaves.
Mulberry is grown as a bush in tropical countries and as middlings and trees in temperate countries like Japan where silkworms can be reared only in three seasons a year. With an object of increasing the production of mulberry and reducing the cost of production, attention has been paid to intensive cultural operations including application of economic dosage of fertilizer and adoption of suitable irrigation schedules. Furthermore, research conducted on breeding of mulberry has resulted in evolving over 200 varieties of mulberry. Studies on ecological factors and adaptability of these varieties have helped in selecting varieties suitable to different agro-climatic tracts. Studies on the horticultural aspects of the plants have helped in adapting various training, pruning and other plant regulatory cultural practices to make the plants grow as bush, middlings or trees, with economic production of leaf.
With efficient use of mulberry leaf, coupled with pruning programmes, it has been possible in sericulturally advanced countries like Japan to rear, silkworms thrice a rear, utilizing the second leaf harvest. In India, by following bottom pruning of the crop it has been possible to harvest more and better quality leaf. This has also made possible artificial hatching of bivoltine silkworm eggs and rearing of polyvoltine silkworms in a commercial manner in India.