• International Journal of Industrial Entomology and Biomaterials
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• 제4권1호
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• pp.37-41
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• 2002

Heterosis studies on rearing performance of 25 Fl Polyvoltine $\times$ bivoltine (sex-limited cocoon colour) hybrids revealed that manifestation of heterosis was highly significant for majority of the economic traits contributing to more silk yield. Five hybrids namely BL24${\times}$ CSR 19 (SL), BL24${\times}$${\times}$${\times}$${\times}$${\times}$

• International Journal of Industrial Entomology and Biomaterials
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• 제3권1호
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• pp.83-88
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• 2001

The effect of topical application with 200,400 and 600 $\mu$g/ml 2,4-dichlorophenoxyacetic acid (2,4-D) on the fifth larval stadium of the silkworm, B. mori, was analyzed. Larvae treated during fifth larval stadium enhanced larval, cocoon and adult parameters. The larval period was significantly decreased with increase in silk gland weight at 400 and 600 $\mu$g/ml, male cocoon weight and shel1 weight in all the treated groups and filament length and weight at 200 $\mu$g/ml treated group. Length of the ovariole, eggs per ovariole and hatching percentage increased significantly in all the treated groups when compared with those of the carrier control. This suggests that the plant growth regulator 2,4-D in addition to affecting silk production also affect reproductive performance.

• International Journal of Industrial Entomology and Biomaterials
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• 제9권1호
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• pp.53-58
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• 2004

Studies on heterotic expression in the silk productivity of 66 thermo-tolerant bivoltine hybrids reared under high temperature $(36{\times}1^{\circ}C)$ and low humidity (60${\times}$5%) conditions revealed that manifestation of heterosis was highly significant for majority of the quantitative traits contributing to more cocoon productivity. Observations were made on 8 economically important traits such as fecundity, pupation rate, cocoon yield, cocoon weight, cocoon shell weight, cocoon shell ratio, cocoon filament length and raw silk. Analysis of variance results revealed great deal of variability indicating significant (P < 0.001) variations. Out of 66 hybrids, 7 hybrids exhibited positive heterosis for seven traits and 4 hybrids expressed significant hetero-beltiosis for 6 traits, out of 8 traits evaluated. Based on results, the hybrids ${SR_1} {\times} {SR_5}and {CSR_2} {\times} {SR_5}$ are adjudged as most promising ones and can be exploited commercially in tropical climates to increase the cocoon productivity.

• International Journal of Industrial Entomology and Biomaterials
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• 제7권1호
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• pp.29-36
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• 2003

Phytoecdysteroids with moulting hormone (MH) activity induce different responses in silkworms when used on different day of final instar, which can be manipulated for maximum benefit like early and uniform spinning behaviour, reducing crop loss and to increase cocoon yield. The results showed that application of this hormone on seed crop viz., CSR2, CSR4 and BL44 and BL67 in early stage of 5$^{th}$ instar i.e., at 72 hrs and 96 hrs though induced early and uniform spinning behaviour, there was an adverse effect by 9-36% on the economic characters like cocoon yield, cocoon weight, cocoon shell weight and also on fecundity etc. Application of this hormone in late stage of $5^th$ instar i.e., at the onset of spinning showed non-significant variations in some of the characters like cocoon weight, cocoon shell weight, cocoon shell ratio and fecundity. The physiological implications of phytoecdysteroid in hastening the maturation events and synchronization of spinning activities in different breeds are discussed.

• International Journal of Industrial Entomology and Biomaterials
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• 제40권2호
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• pp.41-50
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• 2020

Vermicompost, manure, compost and organic fertilization are ecofriendly. Nowadays, many products resulted from sericulture consumed by humans such as mulberry leaves, fruits, mulberry tea, silk and natural silk cosmetics. Soil applications of three treatments with vermicompost (0.5, 1 and 2 tons per 0.42 hectare) and recommended rate of mineral fertilizers of nitrogen phosphorus potassium were used for investigation. Impact of fertilization on mulberry plant traits of moisture, number of shoots/tree, total shoots length/tree, number of leaves/shoot, number of leaves/ (100g), leaf yield/tree and leaf yield of fadden/season were recorded. In addition the effect of fertilization on larval and cocoon characters of young instar duration, fifth instar duration, total larval duration, larval mortality percentage, weight of third instar larvae, weight of fourth instar larvae, weight of fifth instar larvae, fresh cocoon weight, fresh shell weight, pupae weight, cocoon shell ratio, silk productivity, cocooning percentage, pupation ratio, number of cocoons/ liter, crop cocoons by number, crop cocoons by weight, fecundity and fertility. Using vermicompost treatment was enhancing plant characters. Treatments of V₃, V₂ and V₁ were shortage young, fifth and larvae durations. Mostly feeding silkworm during the whole larval duration on treated mulberry leaves with vermicompost improving the traits average. Using vermicompost for fertilization by rate of V₃ and V₂ is better than others for cocoon characters for females and males.V₃ and V₂ of vermicompost per 0.42 hectare is recommended for rearing mulberry silkworm instead of mineral fertilization.

• 한국잠사곤충학회지
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• 제41권2호
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• pp.94-101
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• 1999

Twelve pure silkworm lines identified based in higher G.C.A values from a line${\times}$Tecter crossing programme, were crossed with twelve breeds showing cocoon shell ratio>22% and hybrids prepared, evaluated in a Multiple index method. Seven hydrids showing average index value>50 in all the 10 economic characters were seclcted and evaluated in the laboratory. However, two hybrids viz., A3${\times}$935E and A3${\times}$916B were finally selected based on the superiority of the breeds in one day shorter larval duration and with and with higher reeling characters compared to control KA${\times}$NB4D2. The breeding procedure involed in evolution hybrids are discussed.

• 한국잠사곤충학회지
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• 제14권2호
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• pp.73-79
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• 1972

인삼의 추출용액 및 비여과용액을 누에에 첨식하였을 경우 누에성육 및 형질에 미치는 영향을 알고자 1971년 춘잠, 하잠 및 만추잠, 1972년 춘잠 및 추잠기에 각종농도 및 첨식시기를 달리한 결과에서 1. 인삼용액첨식이 잠작에 미치는 영향은 어떤 농도나, 어느 령기 급여에 있어서도 인정할 수 없었다. 2. 인삼 비여과용액 첨식은 오히려 누에 생리에 나쁜 영향을 미치는 것 같다.

• 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.

• 한국잠사곤충학회지
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• 제27권1호
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• pp.31-36
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• 1985

한성반문 및 한성란색 계통잠에 있어서 전좌염색체로 인한 생리적 결함이 전견중, 견층중 및 견층비율에 미치는 영향을 이들에 관한 성차를 지표로 하여 검토한 결과, 한성 및 비한성 계통견의 전견중의 성차 평균치는 각각 127%, 129%, 견층중의 성차는 각각 107%, 110%, 견층비율의 성차는 공히 85%였다. 이상의 결과에서 한성반문 및 한성 난색계통잠은 전견중, 견층중, 견층비율 등의 실용형질에 관한 한 전좌된 염색체편에 기인하는 생리적 결함은 극히 미소한 것으로 생각된다.

• International Journal of Industrial Entomology and Biomaterials
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• 제18권1호
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• pp.8-12
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• 2009

A study has been made to know the effect of a phytoecdysteroid 'Sampoorna' on uniform maturation of silkworms during spinning and its effect on diseased silkworms infected by major silkworm disease viruses, Bombyx mori nuclear polyhedrosis virus (BmNPV) and Bombyx mori infectious flacherie virus (BmIFV). In the present investigation, the effect of the phytoecdysteroid "Sampoorna" on Grasserie disease caused by BmNPV have shown an average cocoon melting of 11.91% with a disease incidence of 5.83%. The values of 't' test for different treatments of BmNPV indicated low survival rate and cocoon traits were drastically reduced. Another major disease Flacherie caused by BmIFV has shown considerable levels of larval disease incidence (22-32%) and cocoon melting (3-7.67%) with an average melting of 12.95% and 20.24% disease incidence. There is a drastic reduction in survival rate, cocoon yield and other economic traits. The control batches were indicated negligible values for disease incidence and cocoon melting with Sapoorna application and without the inoculation of the two disease-causing viruses. The application of Sampoorna on already infected batches with major pathogens triggered high mortality and disease incidence and melting percentage was also significantly increased with reduced economic traits. Hence, it is suggested that application of Sampoorna in infected batches should be done only in the extreme conditions of rearing. Application of Sampoorna on healthy batches led to uniform maturation and improvement in productivity with the added advantage of better quality cocoons and labour saving.