• International Journal of Industrial Entomology and Biomaterials
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• v.9 no.1
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• pp.35-40
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• 2004

Bombyx mori densonucleosis virus type 1 (BmDNV1)- a non occluded virus causes flacherie disease in the susceptible stocks of the silkworm, Bombyx mori. However, some stocks are non-susceptible. Non-susceptibility to BmDNV1 in B. mori is a unique case where the virus infection is completely inhibited by a single gene of the host. A survey conducted by this institute in some parts of Karnataka state has revealed that, 43.05% of the total incidence of flacherie disease caused by non-occluded viruses, are due to the synergistic infection of B. mori densonucleosis and infectious flacherie virus. Earlier study indicated that rearing of BmDNV1 resistant silkworm stock is effective in protecting silkworm against BmIFV also. In the present study the response of 78 silkworm stocks which include 42 of non-diapausing and 36 of diapausing groups, to BmDNV1 is investigated. Newly ecdysed third instar larvae were inoculated per-os with 10% inoculum of BmDNV1 extracted from the mid-gut of infected silkworm. One non-diapausing and three diapausing silkworm stocks were found to be resistant to BmDNV1. Eleven silkworm stocks were found to possess moderate resistance whereas rest sixty three were found to be susceptible to BmDNV1. Genetic analysis has shown that the resistance to BmDNV1 is autosomally inherited and controlled by a major dominant or a major recessive gene in different silkworm stocks. These resistant stocks can be utilized as the resource material to develop BmDNV1 resistant commercial hybrids. The selection strategies, depending upon the mode of inheritance of resistance in the resource material chosen, are discussed.

• International Journal of Industrial Entomology and Biomaterials
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• v.20 no.2
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• pp.115-116
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• 2010

The Eolrukmal and Hukpyobeom varieties were bred for special purpose such as experience and education. The Eolrukmal variety was selected and succeeded from the $F_1$ of Huka$\times$Galwon in 2004 summer. It has stripes and brown half-moon body marks. The Hukpyobeom variety was selected and succeeded from the $F_1$ of Remone$\times$Hukho in 2004 summer. It has black body color and bright yellow segments. They are healthy yellow cocoon spining varieties showing over 93% of high practical hatching ratio and 93.1% of emergence ratio. The Eolrukmal moth laid 450 egg/batch and the Hukpyobeom moth laid 440 egg/batch.

• International Journal of Industrial Entomology and Biomaterials
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• v.33 no.2
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• pp.113-120
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• 2016

Bombyx mandarina is widely accepted as ancestor of B. mori. Silkworms are served as well-characterized models for understanding the mechanism for the genetic regulation of development. In this study, we performed RNA-Seq analysis to examine tissue-expression of gloverin isoforms of the silk-gland, mid-gut, and fat body in B. mandarina. BLAST analysis revealed that four gloverin isoform gene sequences of B. mandarina were highly similar to B. mori. To identify the difference between two species, the expression profile of gloverin was measured by semi- RT-PCR analysis. The specific expression of gloverin isoform genes was observed mainly in the fat body from B. mori but not B. mandarina. However, all of tissues in the wild-type silkworm could induce the upregulation of compared with the B. mori. To validate the sudden increase in gloverin gene expression in the mid-gut tissue of B. mandarina, we were using qRT-PCR. Relative mRNA expression rate of gloverin at the wild-type silkworm was much higher than domestic silkworm. Comparative genomics between domesticated and wild silkworms showed different tissue-expression levels in some of immune related genes. These results are suggesting a trend toward decreasing immunity related genes expression during domestication. Further studies are needed to elucidate the silkworm domestication and an invaluable resource for wild silkworm genomics research.

• Journal of Sericultural and Entomological Science
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• v.51 no.1
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• pp.20-29
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• 2013

Countries of the world are competing for the collection and utilization of genetic resources, which is a resource of value-added industrialization. We are building database of silkworm and mulberry resources with morphological, genetic characteristics data etc. Moreover, recent bioactive compound has been receiving increasing attention. So we analyzed 1-deoxynojirimycin(1-DNJ) content as a this item in addition to the basic information using 363 strains(varieties) of mulberry genetic resources. They were grown under the same environment and conditions. Mulberry leaves were collected and then freeze-dried and powdered for 1-DNJ test. As a result, 1-DNJ mean content of 363 mulberry strains was $0.176{\pm}0.077%$, and the coefficient of variation (CV) was 43.5%. The variation between the strains was greatly severe. Among the tested strains, 'C1D89/29' was showed the highest content of 0.47%, whereas 'Pumbo 24' and 'Turkey E' were showed the lowest content of 0.05% respectively. The content of 1-DNJ of 16 mulberry varieties for silkworm rearing were compared. Average concentration was $0.17{\pm}0.04%$, and the coefficient of variation (CV) was 22.8%. Variation among cultivars was not significant. Finally we selected 1-DNJ high-containing 11 strains. They are as follows. 'C1D89/29', 'Hiihak', 'Jeokasibmunja', 'Gweonchil', 'Botongsibmunja', 'Jeokchuk', 'bulguksang', 'Geunsookgojo', 'Busanggeum', 'Guksang 20' and 'Taekwang' which are more than twice of the overall average content.

• International Journal of Industrial Entomology and Biomaterials
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• v.4 no.2
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• pp.121-126
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• 2002

Breeding programme was initiated during November, 1995 with the main objective to breed productive multivoltine breeds/ hybrids with suitable genetic constitution to suit the fluctuating tropical climate prevailed in India. Two multivoltine breeds viz., BL-24 and BL-27 selected were as breeding resource materials from the silkworm germplasm maintained at Central Sericul-tural Research and Training Institute, Mysore. By adopting hybridization, backcrossing inbreeding and selection, a new multivoltine breed namely BL-67. This breed spins light greenish yellow cocoons and cocoon shape is oval with medium to coarse grains. The evolved breed was crossed with five tropical bivoltine breeds viz., NB4D2, CSR2, CSR5, CSR18 and CSR101 to study the combining ability, and identified a superior hybrid, BL67 ${\times}$ CSR101, named as CAUVERY, The hybrid is characterized by high pupation rate (>95%), high shell weight (> 35 cg), high cocoon shell ratio (> 20%), longer filament length (> 900 m) and high neatness (93) with a renditta of 6.5 producing 2A-3A grade silk. The hybrid is selected for Race Autho-rization test of Central Silk Board.

• Journal of Sericultural and Entomological Science
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• v.52 no.1
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• pp.52-58
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• 2014

We analyzed rutin content using mulberry genetic resources. They were grown under the same environment and conditions. Mulberry leaves were collected and then freeze-dried and powdered for rutin test. As a result, mean content of mulberry strains was $0.52{\pm}0.25%$, and the coefficient of variation (CV) was 47.9%. The variation between the strains was greatly severe. Among the tested strains, 'Buyoungsang' was showed the highest content of 1.37%, whereas 'Cheongeunsipmunja' and 'Mujeonsipmunja' were showed the lowest content of 0.06% respectively. The content of rutin of 16 mulberry varieties for silkworm rearing were compared. 'Cheongolppong' was showed the highest content of 0.69%, whereas 'Cheongilppong' was showed the lowest content of 0.14 %. Finally we selected rutin high-containing 9 strains. They are as follows. 'Buyoungsang', 'Yeulbon', 'Dangsang 5', 'A8', 'Aja', 'Seongsu 5', 'Sawonppong 12', 'Hwanyoupjosaengnosang' and 'Hwansipjosaeng' which are more than twice of the overall average content.