• Journal of Sericultural and Entomological Science
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• v.41 no.2
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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.

• International Journal of Industrial Entomology and Biomaterials
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• v.14 no.2
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• pp.127-135
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• 2007

Precocious metamorphosis was induced in two popular bivoltine breeds i.e. YB and $NB_4D_2$ by an imidazole compound having anti-juvenile hormone activity. The chemical was administered by feeding treatment with mulberry leaf to freshly moulted (0-6 hrs) IV instar larvae. The dose of the chemical was found to be breed specific being 650 ppm for YB and 500 ppm for $NB_4D_2$. The chemical caused complete skipping up of the fifth instar larvae which is most susceptible to diseases. But IV instar was somewhat prolonged. As a result the total larval period was reduced by 4-5 days. However, some of the rearing and reeling parameters like cocoon yield, cocoon weight, shell weight, shell %, filament length and fecundity were reduced for that particular generation only. The effective rate of rearing (ERR %) was significantly increased in trimoulters during the most unfavourable August - September seed crop season. Number of cocoons / kg and number of male moth were significantly higher in trimoulters. These may be useful for preparation of $multi{\times}bi$ hybrid seed. Fine denier was also found in trimoulter cocoon which is the cause of getting fine silk filament from trimoulter cocoons. Normal mating behaviour and emergence pattern was recorded in trimoulters. Bivoltine trimoulter males also showed competence for mating with multivoltine females. These results suggest the possibility of getting trimoulter males during hot and humid seasons when rearing of bivoltine is almost impossible particularly in Eastern and North Eastern India.

• Current Research on Agriculture and Life Sciences
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• v.1
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• pp.55-65
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• 1983

The purpose of this study is to find out influences of several chemicals on the solubility of cocoon sericin in water, and there are several results of use to control the solubility of cocoon sericin in water. The results obtained are summarized as follows : The chemical which shows the strongest accelerating power of the solubility of cocoon sericin in water is Sodium Hydroxide (NaOH), the second is Potassium Hydroxide (KOH), the third is Sodium Silicate ($Na_2SiO_3$), and the weakest is Sodium Bicarbonate ($NaHCO_3$) in order among noticed silk-reeling accelerators. The chemical which shows the strongest inhibiting power of the solubility of cocoon sericin in water is Form Aldehyde (HCHO), the second is Ammonium Alum ($Al_2(SO_4)_2{\cdot}(NH_4)_2SO_4{\cdot}24H_2O$), the third is Acetic Acid ($CH_3COOH$), the weakest is Hydrochloric Acid(HCl) in order among noticed silk-reeling inhibitors. Particulary Hydrochloric Acid (HCl), which is expected to show strong inhibiting power of the solubility of cocoon sericin in water, shows accelerating power of the solubility of cocoon sericin at high temperature over 80 degrees of Celsius thermometer in water.

• Current Research on Agriculture and Life Sciences
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• v.3
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• pp.70-78
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• 1985

The purpose of this study was to find out effects of several chemicals treatment for cocoon sericin. and there was several results of use to control the solubility of cocoon sericin in water. The results obtained was summarized as follows ; The chemicals which showed the strongest accelerating power on the solubility of cocoon sericin in water was sodium peroxide ($Na_2O_2$), the second was sodium carbonate ($Na_2CO_3$), the third was sodium sulfite ($Na_2SO_3$), the weakest was ammonia water ($NH_4OH$) in order among noticed silk-reeling accelerators. The chemicals which showed the inhibiting power on the solubility of cocoon sericin in water was tannic acid ($C_{14}H_{10}O_9$), the second was stannic acid ($Sn(OH)_4$), the third was formic acid (HCOOH) and the weakest was methyl alcohol ($CH_3OH$) in order among noticed silk-reeling inhibitors. Particulary stannic acid and formic acid showed accelerating power on the solubility of cocoon sericin at high temperature over 100 degrees of celsius thermometer in water Methyl alcohol did not show the inhibiting power on the solubility of cocoon sericin in low concentration. (at 1,500-2,000 times)

• Journal of Sericultural and Entomological Science
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• v.30 no.1
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• pp.33-39
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• 1988

In the case of white cocoon, the fluorescence colors are classified as a yellowish fluorescence cocoon(Y.F.C.) and a violet fluorescence cocoon(V.F.C.) by exposing to ultra-violet ray. Accordingly, experiments were carried out to investigate the difference of sericin behaviors between Y.F.C. and V.F.C. by measuring the sericin solubility, surface tension and viscosity of the sericin solution. Also, the reelability of two different type of cocoons was investigated in the silk reeling process. The results were summarized as follows; 1. The sericin solubility of Y.F.C. shell is higher than that of V.F.C. shell with the dissolution temperature and time. It is shown that the sericin solubility curves of Y.F.c. and V.F.C. are similar in shape, but the difference of sericin solubility between Y.F.C. and V.F.C. is more significant at higher bath temperature. 2. The initial sericin dissolution curves of Y.F.C. and V.F.C. cocoon shell can be divided by four parts within the range of dissolving time from 5 minutes to 60 minutes. The initial dissolution velocity of Y.F.C. shell is faster than that of V.F.C. but the velocity difference is negligible after 30 minutes of dissolving time. 3. The gelation of V.F.C. sericin solution is faster than that of Y.F.C. at early stage(in the range of 15 minutes to 60 minutes). 4. In the silk reeling process, the reelability of Y.F.C. is better than that of V.F.C. with about 11%. This is mainly due to the higher sericin solubility in Y.F.C. followed by the fast dissolution velocity.

• Journal of Sericultural and Entomological Science
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• v.10
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• pp.81-88
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• 1969

This study was carried out to investigate the effects of the cocoon cooking by infra red ray heater established in to the cocoon boiling machine. The results were summarized as follows. 1. According to the cocoons, the non bave end breaking percentage of cocoons was increased to 5∼9％ in spring and 2∼10％ in autumn. 2. There was no significant in the raw silk percentage. 3. The irradiation effect by the number of infra-red ray heater was different, namely, the raw silk percentage of the excellent cocoons was increased in case of 1 Kwatt irradiation, and that of the inferior cocoons was increased in the 2 Kwatt irradiation. 4. Reeling efficiency was showed to 14％ maximum and 3％ minimum(index).

• Journal of Sericultural and Entomological Science
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• v.15 no.2
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• pp.21-28
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• 1973

This report is prepared to promote cocoon natures for the use of silk reeling material. It is easily understandable that there must be disuniformity composed with superior group and inferior group in commercial silkworms. If such different groups be seperated by some method, it would be a great contribution for the cocoon production. For a comparative purpose, silkworm sex seperation carried out because male silkworms produce more silk than female worms. The author has developed a new chemical reagent available for the seperation of superior group and inferior group from commercial silkworms, which he has named it as Better Hybrid Controller (BHC). The obtained comparative results are summarized as followings. 1. Basic investigation of BHC application a) In case BHC applied with hybrid worms and pure line, the former one starts to adapt mulberry leaves earlyer than pure line variety. b) The mulberry adapting interval distribution of pure line worms after BHC application showed U type distribution, but hybrid worms showed L type or Poisson's distribution. c) In case of BHC application with silkworms, the longer period application is, the duller distribution was formed. d) When silkworms are seperated in two groups by use of BHC application, the earlyer mulberry adapted group is seemed as stronger than the other part and the group ratio is 2 : 1. 2. Comparation between sex seperation result and better hydrid control (BHC) seperation result. a) The cocoon shell per cent of male worm group showed betweer result than the female group but only 0.4% difference between sexes. b) The cocoon shell per cent of superior group, seperated by BHC, showed 0.7% more than the inferior group. c) The average cocoon shell per cent of BHC treated cocoons showed much more than the Control group as 1.6∼2.4% increase. Enven the inferior group showed better result than the Control. d) Such unexpected result is considered to be the result that BHC application is activating some thing with silkworm physiology. e) On the ether hand, the result of sexes seperated groups or male worm group did not show desirable conclusion as far as cocoon shell per cent is concerned. f) However, when the male group was reeled as silk, it showed much better silk yield or silk per cent of cocoon than the female group as much as one per cent difference between by sexes. Such result was brought by superior silk yield from cocoon shell as much as 87.4%. g) On the other hand, the male group showed lowest non breaking reelable ratio (63%) among all group comparation. h) When we compare cocoon qualities by sex seperation and BHC seperation against the Control, there is no qualitative change, but BHC group showed quantitative promotion with cocoon bave length as much as about hundred meters. i) In case of calculation for productive income of cocoon production, BHC applied group showed about ten per cent income promotion more than the Control. The sexes seperated group, however, showed rather negative result because the male cocoon produced poor weight per box eggs which could not cover it by the inclose of silk yield of it. j) So, the BHC application with the fetched worm stage brought about big promotion for cocoon production. k) BHC method may be used either for seperation purpose or quantitative promotion with whole silk-worms. 3. Only male silkworms rearing did not show desirable productivity, so there is no reason to work out it in the fetching stage of worm.

• International Journal of Industrial Entomology and Biomaterials
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• v.23 no.2
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• pp.187-191
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• 2011

An attempt was made to assess the potentiality of bivoltine double hybrids under simulated conditions of farmers to identify the suitable bivoltine double hybrid combination. Four bivoltine double hybrids developed at Central Sericultural Research and Training Institute (CSRTI), Mysore along with popular single hybrid, $CSR2{\times}CSR4$ as control was assessed for economic traits. The rearing results showed significant improvement of 20-24% in fecundity of the double hybrids studied over single hybrid. Among the double hybrids, $[D7{\times}S5]{\times}[D13{\times}S1]$ recorded significantly higher survival (89.58 %), cocoon yield (76.328 kg/ 50,000 eggs), cocoon price (Rs. 180.87/kg) and lower cocoon leaf ratio of 1: 21.80. The performance of the reeling traits were also found significantly superior in $[D7{\times}S5]{\times}[D13{\times}S1]$ with higher filament length (1100 m), reelability (88%), raw silk (18.55%) and neatness (92 points) compared to $CSR2{\times}CSR4$ and other double hybrids evaluated. Besides, the cocoons of $[D7{\times}S5]{\times}[D13{\times}S1]$ exhibit uniformity in size with a standard deviation of < 8. Overall data indicated the superiority of $[D7{\times}S5]{\times}[D13{\times}S1]$ compared to the other hybrids evaluated and it has profound influence in expressing the full potentiality in the field.

• Journal of Sericultural and Entomological Science
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• v.13 no.1
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• pp.49-59
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• 1971

This experiment was conducted, how making use of "Seracol 100", a kind of nonionic surface active reagent, during cocoon cooking and silk reeling process which is mainly used in Korea and developed by one of the authors since 1965. Main purpose of the experiment is to investigate the influence of the activity of the reelability aid reagent on various degree of hardness component and various salts which are contained in filature water being used by silk factories now. Specifically, it was tried to determine the effects of the reelability aid reagent added to each sample water of artificially differentiated the degree of hardness component upon sericin solubility. Some of the major findings are summarized as follows. 1. "Seracol 100", with below 5$^{\circ}$dH water, increased sericin solubility in each sample water, but above $10^{\circ}$dH the effect of it shows a significant relationship with the different degree of hardness component. Besides the component (MgCO$_3$)$_4$ㆍMg(OH)$_2$, generally, the higher the degree of hardness in the water, the less the amount of desolved sericin in the water showed. There is little or no difference between 1000 times diluted "Seracol 100" water and 2000 times diluted "Seracol 100" water in terms of sericin solubility. 2. The different kind of degree of hardness component shows a significant relationship with sericin solubility, In case use of "Seracol 100", Mg hardness component affected on the sericin solubility more than Ca hardness. But in the control, contrary to this, that is Ca hardness component did more than Mg hardness, 3. The different kind of salts in degree of hardness component show a significant relationship with sericin solubility. In the control water, nitrate is the greatest among salts affecting on sericin solubility, next chloride and sulfate are in order. In case of "Seracol 100" water, chloride is the least among salts, below $10^{\circ}$dH, next sulfate and nitrate are in order, and above 15$^{\circ}$dH, next nitrate and sulfate are in order. 4. In case of "Seracol 100" water, the more contained heavy metal salts (Fe, Al, Cu, Mn) in the water, the less sericin solubility showed. It is found that there is little or no difference among other salts in terms of sericin solubility. But alkaline metal salt remarkably increased sericin solubility. 5. In case of "Seracol 100" water, tinting of the water was affected by Ca salts more than by Mg salts. Among other salts, only Al and Fe affected on the tinting of the water, specifically, in view of the fact that "Seracol 100" water increase the tinting of Fe salt water, but decrease the tinting of raw silk. It is thought that "Seracol 100" deter Fe$^{+2}$ from absorbing to raw silk by deteriorating the activity of Fe$^{+2}$ . 6. "Seracol 100" have the effect on osmosis of the water, After treatment until 2hrs the osmosis of 1000 times diluted "Seracol 100" water is the greatest, next orders are 2000 times diluted "Seracol 100" and control. From 2 hrs to 6 hrs the osmosis of 2000 times diluted water is the greatest, next orders are 1000 times diluted water and control. After 6 hrs the osmosis of the water is the same order as above. 7. In view of tile fact that "Seracol 100" have the effect to control the degree of hardness during the treatment of cocoon layer in the water, it is thought that, in varying degree of hardness in the water, there is a significant relationship between "Seracol 100" and degree of hardness components in cocoon layer.

• Journal of Sericultural and Entomological Science
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• v.16 no.1
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• pp.21-48
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• 1974

The studies were carried out to disclose the physical and chemical properties of sericin fraction obtained from silk cocoon shells and its characteristics of swelling and solubility. The following results were obtained. 1. The physical and chemical properties of sericin fraction. 1) In contrast to the easy water soluble sericin, the hard soluble sericin contains fewer amino acids include of polar side radical while the hard soluble amino acid sach as alanine and leucine were detected. 2) The easy soluble amino acids were found mainly on the outer part of the fibroin, but the hard soluble amino acids were located in the near parts to the fibroin. 3) The swelling and solubility of the sericin could be hardly assayed by the analysis of the amino acid composition, and could be considered to tee closely related to the compound of the sericin crystal and secondary structure. 4) The X-ray patterns of the cocoon filament were ring shape, but they disappeared by the degumming treatment. 5) The sericin of tussah silkworm (A. pernyi), showed stronger circular patterns in the meridian than the regular silkworm (Bombyx mori). 6) There was no pattern difference between Fraction A and B. 7) X-ray diffraction patterns of the Sericin 1, ll and 111 were similar except interference of 8.85A (side chain spacing). 8) The amino acids above 150 in molecular weight such as Cys. Tyr. Phe. His. and Arg. were not found quantitatively by the 60 minutes-hydrolysis (6N-HCI). 9) The X-ray Pattern of 4.6A had a tendency to disappear with hot-water, ether, and alcohol treatment. 10) The partial hydrolysis of sericin showed a cirucular interference (2A) on the meridian. 11) The sericin pellet after hydrolysis was considered to be peptides composed with specific amino acids. 12) The decomposing temperature of Sericin 111 was higher than that of Sericin I and II. 13) Thermogram of the inner portioned sericin of the cocoon shell had double endothermic peaks at 165$^{\circ}C$, and 245$^{\circ}C$, and its decomposing temperature was higher than that of other portioned sericin. 14) The infrared spectroscopic properties among sericin I, II, III and sericin extracted from each layer portion of the cocoon shell were similar. II. The characteristics of seriein swelling and solubility related with silk processing. 1) Fifteen minutes was required to dehydrate the free moisture of cocoon shells with centrifugal force controlled at 13${\times}$10$^4$ dyne/g at 3,000 R.P.M. B) It took 30 minutes for the sericin to show positive reaction with the Folin-Ciocaltue reagent at room temperature. 3) The measurable wave length of the visible radiation was 500-750m${\mu}$, and the highest absorbance was observed at the wave length of 650m${\mu}$. 4) The colorimetric analysis should be conducted at 650mu for low concentration (10$\mu\textrm{g}$/$m\ell$), and at 500m${\mu}$ for the higher concentration to obtain an exact analysis. 5) The absorbing curves of sericin and egg albumin at different wave lengths were similar, but the absorbance of the former was slightly higher than that of the latter. 6) The quantity of the sericin measured by the colorimetric analysis, turned out to be less than by the Kjeldahl method. 7) Both temperature and duration in the cocoon cooking process has much effect on the swelling and solubility of the cocoon shells, but the temperature was more influential than the duration of the treatment. 8) The factorial relation between the temperature and the duration of treatment of the cocoon cooking to check for siricin swelling and solubility showed that the treatment duration should be gradually increased to reach optimum swelling and solubility of sericin with low temperature(70$^{\circ}C$) . High temperature, however, showed more sharp increase. 9) The more increased temperature in the drying of fresh cocoons, the less the sericin swelling and solubility were obtained. 10) In a specific cooking duration, the heavier the cocoon shell is, the less the swelling and solubility were obtained. 11) It was considered that there are differences in swelling or solubility between the filaments of each cocoon layer. 12) Sericin swelling or solubility in the cocoon filament was decreased by the wax extraction.. 13) The ionic surface active agent accelerated the swelling and solubility of the sericin at the range of pH 6-7. 14) In the same conditions as above, the cation agent was absorbed into the sericin. 15) In case of the increase of Ca ang Mg in the reeling water, its pH value drifted toward the acidity. 16) A buffering action was observed between the sericin and the water hardness constituents in the reeling water. 17) The effect of calcium on the swelling and solubility of the sericin was more moderate than that of magnecium. 18) The solute of the water hardness constituents increased the electric conductivity in the reeling water.