Historical evidence shows that silk was discovered in China from where the industry spread to other parts the world. Silk has played an important role in the economic life of man ever since its discovery more than 4000 years ago. Even today despite the introduction of artificial fibers, natural silk continues to reign supreme as the “Queen of Textile”. Sericulture was introduced in Taxila locality of Punjab immediately after independence in 1947 through Kashmir which is known to be the gateway of sericulture. Subsequently, it was introduced in and around irrigated Forest Plantation where mulberry (toot) was available in abundance to provide foliage (leaves) to silkworms for feeding. Since then it made a slow but steady progress in Punjab. Sericulture is, even now, one of the major cottage industries in the rural areas of the province. The activity is mainly concentrated around irrigated forest plantations of Changa Manga, Daphar, Chichawatni, Kamalia, Khanewal, Baghat, Kundian and Jauharabad. Besides, it is scattered on small scale in various other parts of the province viz Head Marala, Kot Naina, Sargodha, Faisalabad, Soon skesar valley Mian Channu and Multan etc.
“Natural silk” a dry salivary secretion, consists of two proteins, the inner core of fibroin and outer cover of gum is sericin. It is produced when a full grown silkworm larva spins its cocoon during pre-pupation. It is known as the “Golden Fiber” of the “Golden Queen” of textile and admired all over the world for its sleek and lust. Its products are wonderfully light and soft but strong and smooth and universally accepted by the world top fashion designers for its elegance, colours, dyeing affinity, thermo tolerance and water absorbance.
In addition to making clothes and garments which are harmonious to human skin and comfortable to wear, it is being utilized in making fishing lines, tyre lining, parachute, elastic webs, electrical instruments, certain medicines, in surgery and also for making artificial blood vessels etc. Its pupae are utilized in making soaps and for extraction of oils having vitamins E & K. The excrements of this insect are utilized in making fish, poultry and live stock feed.
The raising and rearing of silkworms for production of silk is called as Sericulture. It involves the incubation of the tiny eggs of the silk moth (Bombyx mori) until they hatch and become worms (larvae of silk moth). After hatching the worms are placed under a layer of gauze on which is spread a layer of finely chopped mulberry leaves. For four weeks the worms (caterpillars) eat almost continuously except the periods of moultings (ecdysis). There are four moultings in the life cycle of silkworm during which the larvae become inactive, raise their heads and stop eating. At the end of this period they are ready to spin their cocoons and dry branches of trees or shrubs are placed in their rearing houses. The larvae climb these branches and spin their cocoons around them in one continuous thread taking about 4-5 days for the process.
The cocoons are first heated in boiling water (50°C– 80°C) to dissolve the gummy substance that holds the cocoon filament in place. After this heating, the filaments from 4 – 8 cocoons are joined and twisted and are then combined with a number of similarly twisted filaments to make a thread that is wound on a reel on the Reeling Machine. When each cocoon is unwounded it is replaced with another one. The resulting thread called raw silk consists usually of 48 individual fibers. The thread is continuous and unlike the thread spun from other natural fibers such as cotton and wool is made up of extremely long fibers. A single cocoon can give 800m to 1200m long filament.
Extension and Educational Services
The propagation and regeneration of mulberry plantation is carried out through raising of mulberry nurseries which are presently raised is two ways.
Raising of Potted Nursery
Shoots/branch cuttings or seeds are sown (In case of indigenous variety) directly in polythene tubes generally 18 - 23 cm long with 5 - 10 cm diameter when filled with soil mixture. Black polythene 0.002 gauge is recommended for this purpose. The tube before filling is punched to make some holes for aeriation.
Raising of Bed Nursery
The hybrid mulberry nursery is raised through vegetative propagation in which branch/shoot cuts of standard size (23cm or 9 inch) are used. In order to raise one acre mulberry bed nursery 40,000 branch cuttings are planted in an acre (0.40 hectare) after completion of earth work at spacing of 1' x 1'. The practice of raising of mulberry nursery is usually done in spring season of every year. The crop of mulberry nursery is harvested during the next spring season after a period of almost one year. The Sericulture Wing has been raising mulberry nurseries with fast growing Japanese hybrid varieties at various sericulture centres of Punjab for production of planting stock for raising of mulberry plantations on farmlands. The saplings are usually available to farmers during the spring season @ Rs.1 per sapling (stump).
Raising of Mulberry Plantation
Mulberry stumps of standard size of 23cm (9 inch) long obtained from bed mulberry nurseries are used for raising of mulberry plantation. For raising of one acre compact mulberry plantation in plain areas 2800 mulberry stumps are planted at spacing of 3' x 5'. The raising of mulberry plantation through mulberry stumps is termed as vegetative propagation and it is done more effectively in hybrid mulberry varieties. Mulberry plantations have been raised on state lands for supply of foliage to landless farmers for silkworm rearing. The mulberry leaf permits are issued @ Rs.150/- to landless farmers who desire to harvest mulberry leaves from state plantations. Only one person is allowed to harvest leaves on each permit during the rearing season.
The technique of linear mulberry plantation is usually practiced in agro-forestry on private lands. In this technique mulberry plants are linearly raised through vegetative propagation along khals, watts and paths etc. on the agriculture land with plant to plant distance of about 5 feet. After completion of silkworm rearing process the mulberry plants are pollarded off (cut) at standard height of 1½ feet and twigs are sold to Basket makers which is another source of income to the farmers A farmers can earn Rs.5000 to Rs.10000 through selling of standing twigs of 500 plants. The pollarding is carried out every year after the end of rearing season or during the autumn season. The mulberry plants can be raised linearly along the watts, khals and paths etc. without making shade on agriculture crops. However, mulberry plants can also be raised in compact shapes alongwith other agriculture crops at spacing of 10' x 6' or 10' x 10' feet as per requirement of the farmers. In this technique regular pollarding operation is carried out to avoid the shades of plants on agriculture crops. Read more