Silkworm Genetics and Breeding

Success of silkworm breeding largely depends upon the initial selection of parents, their effective utilization in desirable combination followed by appropriate selection procedures. Silkworm breeders across the country contributed significantly to the development of many bivoltine breeds not only with improved economic parameters but also having suitability for variable climatic conditions. With this aim, the study was carried out to evaluate the performance of the nineteen bivoltine silkworm genotypes viz., Chaung Naung, Sanish-18(M), Pam 114, Pam 117, CSR2, CSR6, CSR26, CSR27, CSR47, S8, N5, SK-6, SK-7, B.Con-1, B.Con-4, Dun-6, Dun-22, APS-4 and APS-5 evolved/maintained by different breeding institutes of India. The evaluation of the selected genotypes was carried out for various traits during spring (May-June), summer (July-August) and autumn (August-September) season 2018 at Central Sericultural Research and Training Institute, Central Silk Board, Pampore, Kashmir. On the basis of the evaluation index values ranking, the high performing silkworm genotypes were identified for spring, summer and autumn seasons which will serve as breeding resource material for further identification of season-specific hybrids for Kashmir Division of J&K state. The study revealed that genotypes Pam 117, CSR 2 and CSR 27 performed better in all the three rearing seasons’ viz., spring, summer and autumn.

In the 19th century, the Hudâvendigâr province was one the most important centers of sericulture and silk industry in The Ottoman Empire territories. Depending on the technological developments and demands taking place in Europe, a significant revival in silk industry was observed in this century. However, when the silk-worms diseases put the activities of the sector to a standstill after the year 1860, the Ottoman government entered into an intensive effort to solve the crisis. After a while, when Ottoman Public Debt Administration was founded to collect the debts belong to the Ottoman Empire by foreign payees, this administration got the right to collect the revenues from silk tithe. In this context, the efforts to increase the revenues initiated a new process that would guide the sericulture sector and revitalize the sector.

According to oldest records the first time silkworm was cultivated and silk was obtained from cocoonat China. Silkworm eggs and mulberry seeds was brought to Istanbul illegally the year 552 at age of Byzantine Empire although China kept it as a secret. It started to spread Marmara region especially Bursa and It’s neighbourhood. Then it was spreaded to all over the world. Sericulture have been economical, cultural and traditional cultivating sector at Turkey for 1500 years. Silkworm is cultivated at about 30 countries that include Turkey. Silk fiber is superior to other fibers in terms of stability, flexibility and brightness. Amount of need is approximately twice the amount of cultivating. In whole world Turkish silk fiber quality is at second rank after japanese silk. Silkworm is a general term that includes a range from worm to the butterfly. Silkworm is a kind of night butterflies. Butterflies are light cream colour have chubby bodies and have soft feathers. Wingspan is about 4-5 cm. Butterfly have lost flying ability because of domestication also have 2 or 3 days life and at that period doesn’t feed and doesn’t fly. Silkworm is fed with mulberry leaves. One cocoon is made from a single silk fiber it’s lenght is 800 meters. Real silkworm named “Bombyx Mori L” is bred at mulberry tree which is cultivated at China is white breed. Bombyx Mori L silkworm produces best silk fiber amoung other genus and it is most special genus cultivated.

The purpose of this article is to review silkworm (Bombyx mori) as a genetic resources of Turkey. Sericulture which gave the name " The Silk Road " to the old world " s trade routes between east and west, has an important role at financial activities for centuries. Journey of the silkworm from cocoon to fibre, fiber to fabric and fabric to clothes has affected the culturel dimension of social life. Sericulture has affected some traditional believes and practices. Some customs and believes have important role on every stage of conventional sericultural applications. Such as incensing at pupa " s room, not allowing anyone to enter pupa " s room against evil eye. The belongings of girls who will be bride such as dowry and bridal dresses have been made from silk. Dowry that includes handkerchief, clothing and underclothing, prayerrug, Quran case, curtain, sofa coat, scarf, " yazma " , bath clothing, and muslin used to be made from silk. A lot of poems and folk songs of folk artists include silk motifs. Some traditional believes and practices of sericulture that exist from ancient ages are examined in this rewiev.

Improvement of Eri Silkworm (Samia ricini D.) Tolerant to High
Temperature and Low Humidity Conditions by Continuously
Regime
Duanpen Wongsorn1, 2 Sivilai Sirimungkararat1, 2, 3* and Weerasak Saksirirat2, 3
1Entomology Section, Department of Plant Science and Agricultural Resource, Faculty of Agriculture,
Khon Kaen University, Khon Kaen 40002, Thailand
2Cultivation and Product Development Research Group of Wild Silkmoths and Economic Insects for Value
Added Creation, Khon Kaen University, Khon Kaen 40002, Thailand
3 Agricultural Biotechnology Research Center for Sustainable Economy and Center of Agricultural
Biotechnology (AG- BIO/PERDO-CHE), Faculty of Agriculture, Khon Kaen University, Khon Kaen
40002, Thailand
* Correspondent Author: sivilai@kku.ac.th
Abstract
Improvement of eri silkworm tolerant to high temperature condition was carried
out by selection and continuous rearing (1-12 generation) under high temperature
(42±1 °C) and low relative humidity (50±5%R.H.). The eri silkworm rearing at a normal
temperature (25±2 °C; 80±5%R.H.) served as control treatment. The result revealed that
eri silkworm was continuously tolerant to high temperature of 42±1˚C with low relative
humidity (50±5%R.H.) up to 12 generations. Among treated generations with high
temperature, the silkworms survived from larva stage (1st-5th instar) to adult in all
generations ranking 16.67-54.17%. Between F12 and F1, survival rate of larva-adult stage
of F12 was 43.33% less than F1 (54.17%), but not significantly different (P<0.05).
For cocoon yields, fresh cocoon weight, pupa weight and cocoon shell weight of F12
were lower than F1. Of F12, shell ratio (11.84%), total cocoon shell weight (5.72g)
and fresh cocoon weight/10,000 larvae (9.39 kg) were not significantly different to F1
(11.61 %, 6.10 g and 10.55 kg, respectively). It was clearly, if the egg yields were
considered, egg laying/moth, total egg laying and total hatchability of F12 were higher
than F1. The result indicates that the thermotolerant property of eri silkworm SaKKU1
is heritable by high temperature at least 12 generations. This study is a first report on
continuously heat tolerant improvement of eri silkworm in Thailand and elsewhere.
Keywords: eri silkworm, tolerance, high temperature, low humidity, Samia ricini

The present study was undertaken to evaluate the performance of eleven bivoltine silkworm, Bombyx mori L, breeds (CSR2, CSR6, CSR27, CSR26, CSR50, PAM114, PAM117, APS4, APS5, SK6 and SK7) of different origin under temperate climatic conditions during spring, summer and autumn, 2018 at Central Sericultural Research and Training Institute, Pampore, Jammu and Kashmir. The rearing was carried out under uniformed laboratory condition by adopting the standard method. These eleven breeds were evaluated for their performance in eight metric traits viz., fecundity (No.), hatching (%), yield per 10,000 larvae by number and by weight (kg), single cocoon weight (g), single shell weight (g), shell ratio (%) and pupation rate (%). The performance of breeds varied from season to season since they originated from different progenitors. The data generated was analyzed statistically and subjected to multiple trait Evaluation index (E.I). On the basis of the evaluation index values ranking CSR2, CSR26, CSR27, CSR50, PAM114 and PAM117 performed well in all the three seasons with E.I values above 50. Two breeds APS5 and CSR6 recorded E.I values below 50 in all the three seasons. APS4 has performed well in only spring season whereas SK6 and SK7 recorded E.I values above 50 in summer and autumn only. Based on their performance in all the three seasons, these parental breeds will be utilized for development of foundation crosses which will be further shortlisted for the development of bivoltine silkworm double hybrids suitable to temperate region of J&K as an alternate for ruling CSR double hybrid.

The present investigation was carried out to improve the selected quantitative traits under uniform laboratory conditions utilizing twenty five breeding lines (BL) of silkworm Bombyx mori L. during autumn season, 2017 in temperate climatic conditions of Kashmir. The breeding lines were reared over five generations and data were recorded as per the standard procedure for the calculation of all the quantitative traits namely, Fecundity (no.), hatching percentage, yield by number & weight (kg)/ 10,000 larvae brushed, single cocoon weight (g), single shell weight (g), shell ratio (%) and pupation rate (%). The data generated were subjected to the multiple trait evaluation index and among all the breeding lines, eighteen lines viz., L-1, L-2, L-3, L-4, L-6, L-7, L-11, L-12, L-14, L-15, L-16, L-7, L-18, L-19, L-20, L-21, L-22 and L-24 exhibited better performance with >50 evaluation index values, L-4 & L-9 observed moderate and L-8, L-10, L-13, L-23 & L-25 recorded least evaluation index during autumn season. Based on the results obtained from the study, the traits differences were observed between the twenty five breeding lines to be considered as the variable effects among the lines during autumn season. It is found that, the 18 lines with >50 evaluation index values have shown significant influence on the expression of quantitative traits and have economical importance under the study. Hence, obtained results from the study will conveniently be utilized for selecting best breeding lines for evolving suitable breeds during autumn season in temperate region of the Kashmir and will be helpful in the field of silkworm breeding and genetics programmes.

—The present study was undertaken to assess the performance of autumn crop (August-September) over spring (May-June) in temperate region of Jammu and Kashmir by rearing the silkworm hybrid (CSR 2 ×CSR 4) in both spring and autumn seasons 2016. The rearing was carried out under uniformed laboratory condition by adopting standard method at Central Sericultural Research and Training Institute (CSR&TI), Central Silk Board, Pampore, Jammu and Kashmir. The farmers were more interested towards spring crop than autumn crop as in autumn crop the cocoon productivity is less as compared to spring, which may be due to leaf quality, disease incidence like BmNPV, etc during autumn season. These aspects can be managed by preventive measures if followed properly by the rearers. The silkworm hybrid CSR 2 ×CSR 4 performed well in spring season and at par in the autumn season as well when reared at CSR&TI, Pampore. A well established mulberry plantation of KNG (Japanese) for chawki rearing and Goshoerami (Japanese) for late age rearing with uniform growth and vigour were used for the study. The rearing results revealed that hatching percentage was 97.47% in spring and 97.30% in autumn and shell ratio (SR %) was 22.09% in spring and 21.42% in autumn. The total cocoon yield per 100 dfls (disease free layings) was 60.90 kg and 57.33 kg in spring and autumn seasons respectively and pupation rate was 91.50% and 91.03% in spring and autumn seasons respectively. The present results indicate that by maintaining proper hygiene and quality leaf, the cocoon productivity in autumn season can be obtained at par with the spring season.

The aim of this paper is to review sericulture in Turkey. Sericulture which gave the name The Silk Road to the old world's trade routes between east and west has an important role at financial activities for centuries. Sericulture production was begun in Anatolia which is Asian part of Turkey in A.D. 552 during Byzantium Emperor of Justinianus. The city of Bursa became a textile city which was famous for silk and silk trade centre. In middle of 16 th century silk textile industry was developed. Apart from city of Bursa, cities of Istanbul, Edirne, Amasya, Denizli, Izmir and Konya were important sericulture centers. Bursa was the important city where silkworm egg and cocoon were produced; silk and velvet were woven by hand and exported to the Europe in the period of Ottoman Empire. Sericulture has begun at the same period in Amasya that is one of the Ottoman cities. Sericulture and cocoon cultivating were made in Mugla the city has eligible climate condition to cultivate mulberry. In Turkey the silk was woven by using simple bench as a family work.

Protein Expression of Eri Silkworm (Samia ricini D.)
Duanpen Wongsorn1, 2 Sivilai Sirimungkararat1, 2, 3* and Weerasak Saksirirat2, 3
1Entomology Section, Department of Plant Science and Agricultural Resources, Faculty of Agriculture,
Khon Kaen University, Khon Kaen 40002, Thailand
2Cultivation and Product Development Research Group of Wild Silkmoths and Economic Insects for Value
Added Creation, Khon Kaen University, Khon Kaen 40002, Thailand
3Agricultural Biotechnology Research Center for Sustainable Economy and Center of Agricultural
Biotechnology (AG- BIO/PERDO-CHE), Faculty of Agriculture, Khon Kaen University, Khon Kaen
40002, Thailand
* Correspondent Author: sivilai@kku.ac.th
Abstract
The effect of high temperatures on growth, yields and heat shock protein (HSP)
production of eri silkworm (Samia ricini D.) was carried out by exposure the 5th instar day
3 larvae to different temperatures, 36±1, 40±1, 42±1, 45±1 and 48±1°C for 3 hours,
compared to control treatment by rearing eri silkworm continuously at normal temperature
(25±2°C, 80±5%R.H.). After treated with high temperature condition, the eri silkworm
larvae were reared at 25±2°C, 80±5%R.H. until cocooning, pupation, adult stage, coupling
and laying eggs. The result exhibited that survival rates, cocooning rate and almost yields
varied inversely to temperatures especially between 42±1-48±1°C. At the highest
temperature, survivals and yields were the lowest, while those values were the maximum
in almost control treatments. At 48±1°C treatment, the means of all parameters were the
lowest; larva survival (50.00%), survival of larva-adult (38.33%) and cocooning rate
(41.67%), which were significantly different to other treatments (P<0.05). Other yields
affected by 48±1°C were also the lowest; fresh cocoon weight (2.5078 g), pupa weight
(2.1508 g), shell weight (0.3429 g), total cocoon shell weight (2.88 g), fresh cocoon
weight/10,000 larvae (10.47 kg), egg laying/moth (287.56 eggs), hatchability (72.67%),
total egg laying (1,121.33 eggs) and total hatchability (800.11 eggs). Detection of HSP of
5th instar larvae day 3 of eri silkworm treated with 5 different temperatures (36±1, 40±1,
42±1, 45±1 and 48±1°C) was performed using sodium dodecyl sulfate polyacrylamide
gel electrophoresis (SDS–PAGE), compared to control treatment (25±2°C; 80±5%R.H.).
The result was clearly that the eri silkworm treated with all high temperatures expressed
HSP bands of approximate 50 kDa. Whereas HSP band was not detectable in control
treatment. The HSP is applicable in the program for thermotolerant variety improvement
of eri silkworm.
Keywords: eri silkworm, high temperature, yield, heat shock protein, effect

Fibroinase is a cathepsin L-like cysteine proteinase isolated from the silk glands of the silkworm, Bombyx mori, and the Eri silkworm, Samia cynthia ricini, and characterized by our research group. In B. mori, its physiological functions are disclosed as follows. (1) During each molt period in the larva, fi broinase is secreted into the lumen of the silk glands and digests the fi broin and sericin completely to make the lumen empty so that the silk gland cells can start synthesizing fi broin and sericin, and then secrete them into the lumen of the silk glands in the late molt period. (2) In day zero to day one pupa, fi broinase is secreted into the lumen of the silk glands and digests the remaining fi broin and sericin. (3) In the feeding period for each instar of the larva and in the spinning period for the last fi fth instar larva, fi broinase functions as a lysosomal proteinase in lysosomes within the silk gland cells for the digestion of obsolete proteins and organelles, such as mitochondria, endoplasmic reticulum, and ribosomal proteins, transported into the lysosomes for regeneration of the highly effi cient protein synthesis machinery. In S. cynthia ricini, the properties of fi boroinase are different in several points from those of B. mori, such as the N-terminal amino acid sequence, developmental profi le, and maximum activity. Higher maximum activity, 38 times the maximum activity of B. mori per individual insect, is observed at the end of spinning. The silk glands of S. cynthia ricini degenerate just after the end of the spinning and the day zero pupa has no silk glands. Accordingly, the physiological functions of fi broinase in S. cynthia ricini are the fi broinase functions (1) and (3) in B. mori. The purpose of this review article is to encourage researchers of insect science to start studying fi broinase of silk glands in other insect species and to fi nd out the species specifi city for a comprehensive view of silk gland fi broinase of a diverse array of insect species. As a guide for the study, we will present the study path in which knowledge of fi broinase in B. mori, and S. cynthia ricini, was obtained with the logic utilized.

Bombyx mori, the domesticated silkworm, is a major insect model for research, and the first lepidopteran for which draft genome sequences became available in 2004. Two independent data sets from wholegenome shotgun sequencing were merged and assembled together with newly obtained fosmid-and BAC-end sequences. The remarkably improved new assembly is presented here. The 8.5-fold sequence coverage of an estimated 432 Mb genome was assembled into scaffolds with an N50 size of w3.7 Mb; the largest scaffold was 14.5 million base pairs. With help of a high-density SNP linkage map, we anchored 87% of the scaffold sequences to all 28 chromosomes. A particular feature was the high repetitive sequence content estimated to be 43.6% and that consisted mainly of transposable elements. We predicted 14,623 gene models based on a GLEAN-based algorithm, a more accurate prediction than the previous gene models for this species. Over three thousand silkworm genes have no homologs in other insect or vertebrate genomes. Some insights into gene evolution and into characteristic biological processes are presented here and in other papers in this issue. The massive silk production correlates with the existence of specific tRNA clusters, and of several sericin genes assembled in a cluster. The silkworm's adaptation to feeding on mulberry leaves, which contain toxic alkaloids, is likely linked to the presence of new-type sucrase genes, apparently acquired from bacteria. The silkworm genome also revealed the cascade of genes involved in the juvenile hormone biosynthesis pathway, and a large number of cuticular protein genes. Fig. 6. The largest Cluster of B. mori cuticular protein genes is on chromosome 22. Most of the cuticular protein genes (52 of 53 genes) belong to the RR2 class.

Bombyx mori, the domesticated silkworm, is a major insect model for research, and the first lepidopteran for which draft genome sequences became available in 2004. Two independent data sets from wholegenome shotgun sequencing were merged and assembled together with newly obtained fosmid-and BAC-end sequences. The remarkably improved new assembly is presented here. The 8.5-fold sequence coverage of an estimated 432 Mb genome was assembled into scaffolds with an N50 size of w3.7 Mb; the largest scaffold was 14.5 million base pairs. With help of a high-density SNP linkage map, we anchored 87% of the scaffold sequences to all 28 chromosomes. A particular feature was the high repetitive sequence content estimated to be 43.6% and that consisted mainly of transposable elements. We predicted 14,623 gene models based on a GLEAN-based algorithm, a more accurate prediction than the previous gene models for this species. Over three thousand silkworm genes have no homologs in other insect or vertebrate genomes. Some insights into gene evolution and into characteristic biological processes are presented here and in other papers in this issue. The massive silk production correlates with the existence of specific tRNA clusters, and of several sericin genes assembled in a cluster. The silkworm's adaptation to feeding on mulberry leaves, which contain toxic alkaloids, is likely linked to the presence of new-type sucrase genes, apparently acquired from bacteria. The silkworm genome also revealed the cascade of genes involved in the juvenile hormone biosynthesis pathway, and a large number of cuticular protein genes. Fig. 6. The largest Cluster of B. mori cuticular protein genes is on chromosome 22. Most of the cuticular protein genes (52 of 53 genes) belong to the RR2 class.

The aim of this paper to review sericulture in Turkey. Sericulture which gave the name “The Silk Road” to the old world’s trade routes between east and west has an important role at financial activities for centuries. Sericulture production was begun in Anatolia which is Asian part of Turkey in A.D. 552 during Byzantium Emperor of Justinianus. The city of Bursa became a textile city which was famous for silk and silk trade centre. In middle of 16th century silk textile ındustry was developed. Apart from city of Bursa, cities of Istanbul, Edirne, Amasya, Denizli, Izmir and Konya were important sericulture centres. Bursa was the important city where silkworm egg and cocoon were produced; silk and velvet were woven by hand and exported to the Europe in the period of Ottoman Empire. Sericulture has begun at the same period in Amasya that is one of the Ottoman cities. Sericulture and cocoon cultivating were made in Mugla the city has eligible climate condition to cultivate mulberry. In Turkey the silk was woven by using simple bench as a family work.

Bombyx mori, the domesticated silkworm, is a major insect model for research, and the first lepidopteran for which draft genome sequences became available in 2004. Two independent data sets from wholegenome shotgun sequencing were merged and assembled together with newly obtained fosmid-and BAC-end sequences. The remarkably improved new assembly is presented here. The 8.5-fold sequence coverage of an estimated 432 Mb genome was assembled into scaffolds with an N50 size of w3.7 Mb; the largest scaffold was 14.5 million base pairs. With help of a high-density SNP linkage map, we anchored 87% of the scaffold sequences to all 28 chromosomes. A particular feature was the high repetitive sequence content estimated to be 43.6% and that consisted mainly of transposable elements. We predicted 14,623 gene models based on a GLEAN-based algorithm, a more accurate prediction than the previous gene models for this species. Over three thousand silkworm genes have no homologs in other insect or vertebrate genomes. Some insights into gene evolution and into characteristic biological processes are presented here and in other papers in this issue. The massive silk production correlates with the existence of specific tRNA clusters, and of several sericin genes assembled in a cluster. The silkworm's adaptation to feeding on mulberry leaves, which contain toxic alkaloids, is likely linked to the presence of new-type sucrase genes, apparently acquired from bacteria. The silkworm genome also revealed the cascade of genes involved in the juvenile hormone biosynthesis pathway, and a large number of cuticular protein genes. Fig. 6. The largest Cluster of B. mori cuticular protein genes is on chromosome 22. Most of the cuticular protein genes (52 of 53 genes) belong to the RR2 class.

Bombyx mori, the domesticated silkworm, is a major insect model for research, and the first lepidopteran for which draft genome sequences became available in 2004. Two independent data sets from wholegenome shotgun sequencing were merged and assembled together with newly obtained fosmid-and BAC-end sequences. The remarkably improved new assembly is presented here. The 8.5-fold sequence coverage of an estimated 432 Mb genome was assembled into scaffolds with an N50 size of w3.7 Mb; the largest scaffold was 14.5 million base pairs. With help of a high-density SNP linkage map, we anchored 87% of the scaffold sequences to all 28 chromosomes. A particular feature was the high repetitive sequence content estimated to be 43.6% and that consisted mainly of transposable elements. We predicted 14,623 gene models based on a GLEAN-based algorithm, a more accurate prediction than the previous gene models for this species. Over three thousand silkworm genes have no homologs in other insect or vertebrate genomes. Some insights into gene evolution and into characteristic biological processes are presented here and in other papers in this issue. The massive silk production correlates with the existence of specific tRNA clusters, and of several sericin genes assembled in a cluster. The silkworm's adaptation to feeding on mulberry leaves, which contain toxic alkaloids, is likely linked to the presence of new-type sucrase genes, apparently acquired from bacteria. The silkworm genome also revealed the cascade of genes involved in the juvenile hormone biosynthesis pathway, and a large number of cuticular protein genes. Fig. 6. The largest Cluster of B. mori cuticular protein genes is on chromosome 22. Most of the cuticular protein genes (52 of 53 genes) belong to the RR2 class.

Improvement of eri silkworm tolerant to high temperature condition was carried out by selection and continuous rearing (1-12 generation) under high temperature (42±1 °C) and low relative humidity (50±5%R.H.). The eri silkworm rearing at a normal temperature (25±2 °C; 80±5%R.H.) served as control treatment. The result revealed that eri silkworm was continuously tolerant to high temperature of 42±1˚C with low relative humidity (50±5%R.H.) up to 12 generations. Among treated generations with high temperature, the silkworms survived from larva stage (1 st-5 th instar) to adult in all generations ranking 16.67-54.17%. Between F12 and F1, survival rate of larva-adult stage of F12 was 43.33% less than F1 (54.17%), but not significantly different (P&lt;0.05). For cocoon yields, fresh cocoon weight, pupa weight and cocoon shell weight of F12 were lower than F1. Of F12, shell ratio (11.84%), total cocoon shell weight (5.72g) and fresh cocoon weight/10,000 larvae (9.39 kg) were not significant...