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Sericulture Reseach & Development Council
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Our Mission
Promotion & development of sericulture & silk industry which is a priority industry because of its being an environment friendly, an effective socioeconomic tool for employment generation in rural areas.

Infrastructural and technical support for production of saplings of silkworm food plant and its plantation and silkworm seed.

Promotion of appropriate & latest technology of sapling raising & plantation of silkworm food plants, silkworm seed, silkworm rearing, silk spinning and silk reeling.

Facilitate marketing of sericulture produces at the optimum market price.
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What is sericulture ?
Sericulture is an agro-based industry. It involves rearing of silkworms for the production of raw silk, which is the yarn obtained out of cocoons spun by certain species of insects. The major activities of sericulture comprises of food-plant cultivation to feed the silkworms which spin silk cocoons and reeling the cocoons for unwinding the silk filament for value added benefits such as processing and weaving.
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The farmers generally buy silkworm eggs (DFLs) from grainages, hatch and rear in their dwelling houses or in the silkworm rearing houses constructed separately.

Egg is the first stage of a silkworm’s life cycle. After mating, each female moth lays around 300 to 400 eggs. Silkworm eggs are flat, ellipsoid or oval in shape and have a tiny pore known as micropyle at the anterior end. They are hard and measure 1.3 – 1.4 mm in length, 0.87- 1.27 mm in widthand around 0.6 mm in thickness. Each egg weighs around 0.5-0.6 mg. Colourvaries in different breeds. Newly laid eggs are pale to dark yellow and the diapausing eggs turn to purplish gray often with green or pink tinge in 24 hours. The embryo develops inside the egg and transforms into larva which normally hatches in about 10 days from the day of laying.

a) Egg



After mating, each female moth lays around 400 eggs. Silkworm eggs are flat,ellipsoid or oval in shape and have a tiny pore known as micropyle at the anteriorend. They are hard and measure 1.3-1.4 mm in length, 0.87- 1.27 mm in widthand around 0.6 mm in thickness. Each egg weighs around 0.5-0.6 mg. Colourvaries in different breeds. Newly laid eggs are pale to dark yellow and the diapausing eggs turn to purplish gray often with green or pink tinge in 24 hours.

The embryo develops inside the egg and transforms into larva which normallyhatches in about 10 days from the day of laying. However, the eggs of temperatebreeds enter into a resting stage called hibernation (winter sleep) or diapause toescape the severe winter during which the mulberry plant also sheds its leaves andenters into a stage of resting known as dormancy. The diapause can be terminatedartificially.



b) Larva

Newly hatched larvae are brown or reddish brown in colour and look like antsto the naked eye. They measure about 3 mm long. They feed on the mulberryleaves and as they grow, the colour gradually turns into greenish white. The larvasheds its skin (integument) four times and this process is called ecdysis or moulting.

During this process, the larvae stops feeding and rest. The period between hatchingand moulting or between two moults or moulting and spinning stage is called aninstar. Thus, the larva passes through five instars in about 25 days and grows by10,000 times in size. The fully grown larva is cylindrical with a convex dorsal sideand a slightly flat ventral side. The body is divided into three regions, head, Thorax comprising of three segments and abdomenconsisting of 9 segmentsThe males are identified by the presence of milky white pear shaped Herold’s glandson the mid-posterior part of the eighth segment on the ventral side. The females are identified by the presence of two pairs of milky dottedstructures, one pair situated in the lateral side of the eighth segment of the ventralside and the other on the ninth segment. They are called Ishiwata’s glands.

c) Pupa



The fully grown larva spins a cocoon around it and transforms into a pupa, aresting stage. It takes about two days to spin the cocoon and another 2-3 daysfor transformation into pupa. The female pupa can be identified by its broaderabdomen, stout tip and an X- shaped mark on the ventral side of the eighthsegment. The male has a narrow abdomen, sharp tip and a dark spot on theventral side of the ninth segment. Though the pupa looks inactive, rapid internal modifications occur resulting in the development of various organs and thusmetamorphose into adult and the moth emerges from the cocoon.



d) Adult (Moth)

The silk moth emerges in 10-12 days from the day of spinning the cocoon. Themoth secretes an alkaline fluid from its mouth which softens the cocoon shellthrough which it pierces and emerges from the cocoon. The moths look likebutterflies, but the wings spread slightly downwards unlike the butterflies. Themoths also do not have any mouthparts and their only purpose is to mate and layeggs to continue their generation. They mate immediately and female lays around400
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26/08/2017
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The farmers generally buy silkworm eggs (DFLs) from grainages, hatch and rear in their dwelling houses or in the silkworm rearing houses constructed separately.

Egg is the first stage of a silkworm’s life cycle. After mating, each female moth lays around 300 to 400 eggs. Silkworm eggs are flat, ellipsoid or oval in shape and have a tiny pore known as micropyle at the anterior end. They are hard and measure 1.3 – 1.4 mm in length, 0.87- 1.27 mm in widthand around 0.6 mm in thickness. Each egg weighs around 0.5-0.6 mg. Colourvaries in different breeds. Newly laid eggs are pale to dark yellow and the diapausing eggs turn to purplish gray often with green or pink tinge in 24 hours. The embryo develops inside the egg and transforms into larva which normally hatches in about 10 days from the day of laying.

a) Egg



After mating, each female moth lays around 400 eggs. Silkworm eggs are flat,ellipsoid or oval in shape and have a tiny pore known as micropyle at the anteriorend. They are hard and measure 1.3-1.4 mm in length, 0.87- 1.27 mm in widthand around 0.6 mm in thickness. Each egg weighs around 0.5-0.6 mg. Colourvaries in different breeds. Newly laid eggs are pale to dark yellow and the diapausing eggs turn to purplish gray often with green or pink tinge in 24 hours.

The embryo develops inside the egg and transforms into larva which normallyhatches in about 10 days from the day of laying. However, the eggs of temperatebreeds enter into a resting stage called hibernation (winter sleep) or diapause toescape the severe winter during which the mulberry plant also sheds its leaves andenters into a stage of resting known as dormancy. The diapause can be terminatedartificially.



b) Larva

Newly hatched larvae are brown or reddish brown in colour and look like antsto the naked eye. They measure about 3 mm long. They feed on the mulberryleaves and as they grow, the colour gradually turns into greenish white. The larvasheds its skin (integument) four times and this process is called ecdysis or moulting.

During this process, the larvae stops feeding and rest. The period between hatchingand moulting or between two moults or moulting and spinning stage is called aninstar. Thus, the larva passes through five instars in about 25 days and grows by10,000 times in size. The fully grown larva is cylindrical with a convex dorsal sideand a slightly flat ventral side. The body is divided into three regions, head, Thorax comprising of three segments and abdomenconsisting of 9 segmentsThe males are identified by the presence of milky white pear shaped Herold’s glandson the mid-posterior part of the eighth segment on the ventral side. The females are identified by the presence of two pairs of milky dottedstructures, one pair situated in the lateral side of the eighth segment of the ventralside and the other on the ninth segment. They are called Ishiwata’s glands.

c) Pupa



The fully grown larva spins a cocoon around it and transforms into a pupa, aresting stage. It takes about two days to spin the cocoon and another 2-3 daysfor transformation into pupa. The female pupa can be identified by its broaderabdomen, stout tip and an X- shaped mark on the ventral side of the eighthsegment. The male has a narrow abdomen, sharp tip and a dark spot on theventral side of the ninth segment. Though the pupa looks inactive, rapid internal modifications occur resulting in the development of various organs and thusmetamorphose into adult and the moth emerges from the cocoon.



d) Adult (Moth)

The silk moth emerges in 10-12 days from the day of spinning the cocoon. Themoth secretes an alkaline fluid from its mouth which softens the cocoon shellthrough which it pierces and emerges from the cocoon. The moths look likebutterflies, but the wings spread slightly downwards unlike the butterflies. Themoths also do not have any mouthparts and their only purpose is to mate and layeggs to continue their generation. They mate immediately and female lays around400
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Most of us are familiar with silk as a fine fabric that is made into neckties and dresses. As a textile, silk is highly valued because it is shiny and smooth, strong yet lightweight, and it can be easily dyed or treated to take on the color or chemical properties of other substances. These well-known properties led scientists to develop new products from silk, including important medical materials such as replacement cartilage, surgical sutures, and small spheres that can be used to deliver drugs to certain parts of the body (not all of these are available yet on the market). What many people do not realize is that the small silk fibers that give silk its desirable characteristics come from the mouths of caterpillars called silkworms.

The silk used by humans comes from the domesticated silkworm, Bombyx mori. The silkworm is the caterpillar of a moth in Lepidoptera, the order of insects that includes moths and butterflies. Lepidoptera are holometabolous insects, which means that they undergo a complete metamorphosis during their lifetime. Just like butterflies, silkworm moths begin their life as an egg that then hatches into a growing, feeding caterpillar. When a silkworm has eaten enough, it constructs a cocoon made out of silk fibers, and inside that cocoon it turns into a pupa. After many days, a fully formed adult silkworm moth emerges through a spit-soaked opening in the bottom of a cocoon.

Dissecting a silkworm cocoon before the adult has emerged provides many clues about the transformation of a silkworm into an adult moth—a change that is normally impossible to view through the walls of a cocoon once it has been constructed. In this activity, you’ll learn about the insect origins of silk by dissecting a cocoon and “degumming” it to reveal the protein, called fibroin, that scientists use for constructing new materials.
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Cocoon Exterior – What is on the outside of a cocoon?

Take a moment to make some observations about the color, shape, weight, size, and texture of the outside of the cocoon. Gently shake the cocoon and listen for anything inside. If you have a scale, measure the mass of the cocoon. Record your observations in a notebook or on the silk cocoon dissection sheet.

Use your fingers to gently tug at the loose silk around the outside of the cocoon. You may find you are able to remove the exterior silk in one single sheet. Rub this silk between your fingers, describing the texture in your notes, then pin it to your pinboard and label it so that you can compare it to silk collected in later steps.

Use your fingers to gently tug at the loose silk around the outside of the cocoon. You may find you are able to remove the exterior silk in one single sheet. Rub this silk between your fingers, describing the texture in your notes, then pin it to your pin board and label it so that you can compare it to silk collected in later steps.


Now, use a pin to snag some of the second layer of silk from the outside of the cocoon. Pull enough that you can feel it between your fingers and observe its texture, and record your observations. Pin this silk next to the silk you pulled off in the previous step, and label it.

A silkworm constructs its cocoon from the outside in, starting with a quick scaffold that it can easily rest upon while weaving and that will ultimately secure the cocoon to surrounding plants. The silk used to make the cocoon starts out thick but gets thinner and thinner as the silkworm works its way into the center of the cocoon.

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8/5/17
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Most of us are familiar with silk as a fine fabric that is made into neckties and dresses. As a textile, silk is highly valued because it is shiny and smooth, strong yet lightweight, and it can be easily dyed or treated to take on the color or chemical properties of other substances. These well-known properties led scientists to develop new products from silk, including important medical materials such as replacement cartilage, surgical sutures, and small spheres that can be used to deliver drugs to certain parts of the body (not all of these are available yet on the market). What many people do not realize is that the small silk fibers that give silk its desirable characteristics come from the mouths of caterpillars called silkworms.

The silk used by humans comes from the domesticated silkworm, Bombyx mori. The silkworm is the caterpillar of a moth in Lepidoptera, the order of insects that includes moths and butterflies. Lepidoptera are holometabolous insects, which means that they undergo a complete metamorphosis during their lifetime. Just like butterflies, silkworm moths begin their life as an egg that then hatches into a growing, feeding caterpillar. When a silkworm has eaten enough, it constructs a cocoon made out of silk fibers, and inside that cocoon it turns into a pupa. After many days, a fully formed adult silkworm moth emerges through a spit-soaked opening in the bottom of a cocoon.

Dissecting a silkworm cocoon before the adult has emerged provides many clues about the transformation of a silkworm into an adult moth—a change that is normally impossible to view through the walls of a cocoon once it has been constructed. In this activity, you’ll learn about the insect origins of silk by dissecting a cocoon and “degumming” it to reveal the protein, called fibroin, that scientists use for constructing new materials.
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Non-mulberry sericigenous fauna belonging to the family Saturniidae (superfamily Bombycoidea) are mostly wild Silkmoths. These are used as important tools in basic entomological and biotechnological research in various countries. These are medium to very large in size, and this family includes the largest moths. Adults have a wingspan of 3 to 15 centimeters, relatively small heads, and densely hairy bodies. Larvae are usually very fleshy, with clumps of raised bristles. Caterpillars mostly feed on leaves of trees and shrubs; some cause severe damage. Pupa develops in silken cocoons. Wild silkmoths are reared on wild trees but can also be raised and bred under complete human control. They complete their life cycle of four different metamorphosing phases, egg, larva, pupa and adult (moths). Of this only larval stage is feeding period. The range of food selection of these insects is wide. Their cocoons are bigger than those of the domesticated silkworm.
Wild silkmoths include tasar silkworm, eri-silkworm, oak-tasar silkworm and muga silkworm. Most of the research and development of technology is confined to China, India, and Japan in Asia. The Indian tasar silkworm Antheraea mylitta is a natural fauna of tropical India, represented by more than 20 ecoraces. Large quantity of Indian and Chinese tasar cocoons are utilized to produce various types of textiles. Antheraea assama (Muga silkworm) (n= 15) is a wild silk moth mentioned in literature as early as 1662 BC. It is widely distributed and cultured in North-Eastern India particularly in Assam state. The golden-yellow muga silk is secreted by this semi-domesticated multivoltine species. Larvae fed on mejankori leaves (Litsea citrata) produce a kind of silk known as mejankori silk, which is favoured for its durability, lustre and creamy white shade. Japanese oak silkworm, Antheraea yamamai is a native of Japan with 31 chromosomes. It is also unique because it contributes to the production of a highly priced silk. Samia cynthia ricini (n= 13) a multivoltine silkworm commonly called as 'eri silkworm' is known for its white or brick-red eri silk. It is distributed in North-Eastern part of India. Its other ecoraces (~16) are distributed across the palaearctic and Indo-australian biogeographic regions. Antheraea pernyi (n=49) is originated in Southern China, dating back to the Han and Wei dynasties. Antheraea roylei (n=30,31,32) is distributed along the Sub-Himalayan belt of India. Antheraea proylei (n=49) is a successful hybrid of the Antheraea roylei with its chinese counterpart.
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"yellow and ebony Are the Responsible Genes for the Larval Color Mutants of the Silkworm Bombyx mori"

Abstract

Many larval color mutants have been obtained in the silkworm Bombyx mori. Mapping of melanin-synthesis genes on the Bombyx linkage map revealed that yellow and ebony genes were located near the chocolate (ch) and sooty (so) loci, respectively. In the ch mutants, body color of neonate larvae and the body markings of elder instar larvae are reddish brown instead of normal black. Mutations at the so locus produce smoky larvae and black pupae. F2 linkage analyses showed that sequence polymorphisms of yellow and ebony genes perfectly cosegregated with the ch and so mutant phenotypes, respectively. Both yellow and ebony were expressed in the epidermis during the molting period when cuticular pigmentation occurred. The spatial expression pattern of yellow transcripts coincided with the larval black markings. In the ch mutants, nonsense mutations of the yellow gene were detected, whereas large deletions of the ebony ORF were detected in the so mutants. These results indicate that yellow and ebony are the responsible genes for the ch and so loci, respectively. Our findings suggest that Yellow promotes melanization, whereas Ebony inhibits melanization in Lepidoptera and that melanin-synthesis enzymes play a critical role in the lepidopteran larval color pattern.

THE extremely diverse lepidopteran color pattern is evolutionarily interesting because of its association with natural selection. Much research has focused on adult wings to study the molecular mechanisms of color patterns. Some of the most convincing data comes from comparative studies between different species (Carroll et al. 1994; Brunetti et al. 2001; Reed and Serfas 2004; Monteiro et al. 2006), phenotypically differentiated laboratory strains, or spontaneous mutants within species (Brakefield et al. 1996; Brunetti et al. 2001, Beldade et al. 2002). A candidate gene approach revealed that the Distal-less gene segregates with the eyespot size phenotype, explaining up to 20% of the phenotypic difference between the selected lines in Bicyclus anynana (Beldade et al. 2002). To determine the responsible genes for color pattern polymorphisms or mutants, an AFLP-based linkage map has been developed in several butterfly species (reviewed in Beldade et al. 2008). Recently, the linkage of forewing color pattern and mate preference with the wingless gene in two Heliconius species (Kronforst et al. 2006) and the linkage of the mimicry locus H with the invected gene in Papilio dardanus have been reported (Clark et al. 2008), although these reports have not elucidated whether wingless or invected is the responsible gene for wing color pattern variation. Until now, no color pattern genes have been elucidated by positional cloning in Lepidoptera.

Like the adult wings, the larvae of butterflies and moths, often preyed on by other animals, also show various color patterns. In the swallowtail butterfly, Papilio xuthus, several melanin-synthesis genes are associated with stage-specific larval color patterns (Futahashi and Fujiwara 2005, 2006, 2007, 2008a). Melanin-synthesis genes are responsible for pigmentation mutants in Drosophila melanogaster (Wright 1987; Wittkopp et al. 2002a); however, the connection between these genes and the color pattern mutants in other insects has not been elucidated.

Although larval color variations are often observed in many Lepidoptera, the genes responsible for color patterns have not yet been identified by mutation studies. Elucidating the genetic basis of lab-generated color mutants is important because it points out the interacting loci in the pathway that produces interesting phenotypes (larval pigmentation in this case) and it highlights genetic changes that could serve as the raw material for evolutionary change. Among lepidopteran species, the silkworm Bombyx mori is the most suitable for identification of mutants because its genome is already available (Mita et al. 2004; Xia et al. 2004); a high-density linkage map has been constructed between p50T and C108T strains (Yamamoto et al. 2006, 2008); and many available color mutants, especially in larval stages, have been obtained (Banno et al. 2005). Here we have analyzed whether melanin-synthesis genes were associated with Bombyx larval color mutants by using linkage analysis and comparing protein structure between wild-type and mutant strains. These genes are predicted to be important for driving patterns of pigmentation that may be used as a mechanism to avoid being preyed upon. Linkage analysis revealed perfect cosegregation between the chocolate (ch) locus and the yellow gene and between the sooty (so) locus and the ebony gene. The spontaneous ch mutant was first reported in Toyama (1909) and was mapped at 9.6 cM of the silkworm genetic linkage group 13 (Suzuki 1942; Banno et al. 2005). In the recessive homozygote of the ch mutant, the larval skin and the head cuticle of newly hatched larvae is reddish brown instead of the normal black (Figure 1B). In grown larvae of the homozygous ch mutants, black body markings and sieve plates of spiracles remain reddish brown (Figure 1A). The so is also a spontaneous mutant (Tanaka 1924) and was mapped at the end of the silkworm genetic linkage group 26 (Banno et al. 1989, 2005). In the recessive homozygote of the so mutant, the pupal color is black, especially at the ventral tip of the abdomen (Figure 1C). From larvae to the adult stage, body color is smoky, but less conspicuous compared to pupae (Figure 1A). Molecular characterization of these pigmentation mutants demonstrated that ch mutants were loss-of-function yellow alleles caused by a deletion or a presumptive splice junction mutation, while the so mutants were loss-of-function ebony alleles caused by deletions present in 3′ exons, suggesting that these two genes were responsible for the black color pattern common among insects.
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