• 한국잠사곤충학회지
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• 제42권1호
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• pp.24-27
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• 2000

A new silkworm variety 'Yangwonjam'for both of spring and autumn rearing season is F$_1$hybrid between Jam 143, a Japanese race bred from H5R1/P8503 and Jam 144, a Chinese race from M8312/8190. This is the first both parent sex-limited larval marking variety in Korea, and which contributes to eggs production of F$_1$hybrid silkworm with saving labor. Jam 143, Japanese parent of the 'Yangwonjam'showed high GCA in pupation percentage and Jam 144, Chinese parent showed high GCA in pupation percentage and single cocoon weight. In the local adaptability test performed at 8 local areas in spring of 1998, Yangwonjam records 1% higher in pupation percentage and 5%, 4% lower in single cocoon weight, cocoon yield from 10,000 3rd molted larvae respectively than the check variety Kumokjam. Also in the resistance test against unfavorable rearing condition performed in spring of 1997, Yangwonjam records 9%, 14% lower in single cocoon weight, cocoon shell weight respectively than the check variety, but showed 1% higher in pupation percentage than check variety.

• International Journal of Industrial Entomology and Biomaterials
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• 제5권1호
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• pp.23-32
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• 2002

The introduction of hybrid and exploitation of heterosis has played a vital role in Indian sericulture industry, which clearly depicts a quantum jump in silk production during the last four decades. Since, the introduction of heterosis, progress in silkworm breeding has depended on success or failure in identifying better combiners. Systematic procedures developed have enabled the breeders to identify the best combiners by combining ability test, line ${\TIMES}$ tester analysis or $D^2$ analysis for maximum expression of heterosis. The level of heterosis expressed in the crossbreed population is determined by the interaction between genotype and prevailing environmental factors. Except some of the pre and post cocoon parameters, heterosis is invariably higher in single crosses compared to three-way and double crosses. However, during hot and humid season, when rearing of F1 bivoltine hybrid is unsuccessful at field level and indigenous races results in very low and poor quality yield, three-way and double crosses can play an important role as an intermediary technology. The objective of this article is to review briefly the concept and causes of heterosis, utilization of different forms of heterosis in silk production and its significance in silkworm, Bombyx mori breeding.

• International Journal of Industrial Entomology and Biomaterials
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• 제32권2호
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• pp.54-59
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• 2016

All of silkworm varieties reared in farmhouses are first generation hybrids, for the production of these hybrid silkworms precise and labor-saving sex discrimination is necessary. The new variety "Hanbyeolnue" is biparental sex-limited larval marking yellow cocoon variety which was bred from biparental sex-limited strain of Japanese originated Jam 319 and Chinese originated Jam 320. Productivity test of Hanbyeolnue in 2015 showed high healthiness and short larval period. The Hanbyeolnue was evaluated as an excellent variety which can be utilized for special purpose silkworm such as male pupae or Cordyceps production.

• International Journal of Industrial Entomology and Biomaterials
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• 제20권2호
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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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• 제14권2호
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• pp.93-97
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• 2007

A Silkworm breeding programme was designed to develop a robust but productive bivoltine silkworm hybrid of Bombyx mori L. suitable for rearing throughout the year in tropical climate by utilizing indigenous polyvoltine and productive bivoltine breeds. The breeding was carried out under high temperature ($36^{\circ}C{\pm}1^{\circ}C$) and low humidity ($50{\pm}5%$) conditions in the environmental chamber. By $F_{12}$, three oval and three dumbbell breeds were isolated with higher survival and productive merits. These breeds were utilized in the hybrid evaluation along with other popular breeds. Based on combining ability test results, the hybrid $SR_2{\times}SR_5$ was selected for large scale testing and evaluated in different seasons. The evaluation studies indicated that the hybrid has higher viability and productive merits and it is suitable to rear throughout the year. The hybrid $SR_2{\times}SR_5$ recorded a survival of 92.0%, cocoon shell weight of 0.417 g, cocoon shell percentage of 23.0 and a filament length of 1042 meters under hot and dry conditions of environmental chamber compared to the control thermo-tolerant hybrid $CSR18{\times}CSR19$.

• International Journal of Industrial Entomology and Biomaterials
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• 제5권1호
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• pp.44-52
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• 2002

To understand the relationship among different quantitative traits, correlation studies were performed by utilizing eighty-eight inbred strains of silkworm, Bombyx mori L. on twelve economic characters. Analysis resulted in correlation of 5th instar period with total larval period (r ＝ 0.7882), cocoon weight with shell weight (r ＝ 0.8326), shell weight with shell ratio (r ＝ 0.5067), shell ratio with raw silk ％ (r ＝ 0.7570), raw silk ％ with filament length (r ＝ 0.3490), filament size (denier) with reelability (r ＝ 0.3193) and boil-off loss % (r ＝ 0.2792). Negative correlation was observed among filament length with filament size (r ＝ 0.7582) and reelability with boil-off loss % (r ＝ -0.3236). Correlation of different quantitative characters for quality silk production is discussed.

• Mycobiology
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• 제38권3호
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• pp.180-183
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• 2010

This study was conducted out to select a silkworm variety suitable for synnemata production of Isaria tenuipes. Four kinds of the mulberry silkworm varieties, Bombyx mori, were hybridized using a Japanese parental line and a Chinese parental line, and used to test for synemata formation in I. tenuipes. The larval period of normal silkworms was 22 hr longer than the silkworms inoculated with this fungus. Among the silkworm varieties tested, Hachojam had the shortest larval period with 23.02 days. The non-cocooning silkworm had a shorter larval period than the cocoon producing silkworms. The pupation rate of normal silkworms was about 9% higher than that of silkworms sprayed with I. tenuipes. Hachojam had the highest infection rate at 99.8%, but no significant difference was observed for the infection rate by silkworm variety. The production of synnemata was the best in JS171 $\times$ CS188 with an incidence rate of 99.3%, followed by Hachojam, and Chugangjam. The synnemata produced from Hachojam were the heaviest and showed white or milky-white in color.

• International Journal of Industrial Entomology and Biomaterials
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• 제40권2호
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• pp.51-55
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• 2020

A new silkworm variety, Juhwangjam, was bred for the producing of light pink colored cocoon. The Juhwangjam variety was selected and succeeded from the F1 of 2303 × BP Heehong in 2016 autumn. Hatchability (96%) and pupation percentage (97.6%) of Juhwangjam was matched to the authorization criteria for commercial silkworm variety. Laval period and other economical characters of Juhwangjam were similar to the authorized silkworm variety, Goldensilk. Cocoon yield of Juhwangjam in spring and autumn season was 20.0 and 14.3 kg, respectively. Therefore, a new silkworm variety, Juhwangjam for light pink cocoon, might be adaptable to culture in spring season rather than autumn season.

• International Journal of Industrial Entomology and Biomaterials
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• 제8권2호
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• pp.129-133
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• 2004

The breeding work was initiated by utilizing two Japanese hybrids namely C135${\times}$N134 and N137${\times}$C146 along with two evolved Indian breeds, J14 and A24. The breed CSR16 which is characterized with marked larvae and white dumbbell cocoons was evolved from the Japanese hybrid C135${\times}$N134 by crossing with J14, while the breed CSR17 which is characterized with plain larvae and white oval cocoons was evolved from the Japanese hybrid N137${\times}$C146 by crossing with A24. The hybrid of these evolved breeds i.e., CSR16${\times}$CSR17 has shown superior over control hybrid $KA{\times}{NB_4}{D_2}$ and on par with the ruling hybrid of CSR2${\times}$CSR4. The hybrid CSR16${\times}$CSR17 was authorized during 1999 by Central Silk Board, Bangalore, Government of India for commercial exploitation during favourable months based on national level race authorization test.

• 한국잠사곤충학회지
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• 제50권1호
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• pp.5-9
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• 2012

수옥잠은 부화비율, 화용비율이 높은 강건 다수성 애누에 인공사료 적합품종을 육성하였다. 이 품종의 일본종계 원종 잠157은 2003년 K305와 9671을 교잡 육성한 무늬품종이고 중국종계 잠158은 1997년에 CBJ와 9032을 교잡 육성한 선발 육성한 무늬 없는 품종이다. 실용 부화비율은 97%, 화용비율은 95.9%로 우수하였고, 전견중이 2.40 g, 1만두 수견량은 22.6 kg, 상견비율 95.5%로 대조 품종과 비슷한 성적을 나타냈다. 실켜기 성적에서 견사장은 대조 1,433 m보다 78 m 짧고, 견사량이 대조 보다 적은 49.6 cg 이었다. 견사섬도는 3.31 d이었다. 이품종의 잠종생산능력은 일본종계 원종 잠157의 산란수는 513개로 대조 대풍잠의 잠151의 525개와 비슷하였고, 중국종계 원종 잠1568 산란수 522개로 대조 잠152의 447보다 105개가 많아 산란성이 우수하였다.