• International Journal of Industrial Entomology and Biomaterials
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• v.1 no.2
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• pp.103-109
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• 2000

To evolve silkworm hybrids with higher survival and better cocoon characters, evaluation of semen hybrids in the laboratory (short-listed out of 143 hybrids) resulted in the identification of two promising hybrids, A3${\tines}$935 E (HSP1) and A3${\tines}$916 B (HSP2). The hybrids were evaluated at three different Regional Sericultural Research Stations of Central Silk Board during 1997-1998 and also tested with the farmers along with two control hybrids, KAxNB4D2 and PMxNB4D2. Evaluation of the hybrids indicated that these hybrids can be reared in all the seasons, especially during summer season. These hybrids show shorter larval duration (22 days 17 hrs against 23 days in control KAxNB4D2 and better cocoon characters as compared to the crossed breeds PM ${\tines}$NB4D2).

• International Journal of Industrial Entomology and Biomaterials
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• v.6 no.1
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• pp.75-79
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• 2003

Oral supplementation of zinc chloride to silkworm larvae in different concentrations (30, 60 and 90 ${\mu}g$/ml) to the fourth and fifth instar resulted in a significant increase in commercial traits, like larval weight, silk gland weight, cocooning percentage in lower concentrartion (30 ${\mu}g$) treated group. The female cocoon weight, shell weight and its ratio were significantly increased in 30 and 60 ${\mu}g$ treated groups, male cocoon weight, and shell weight in 30 ${\mu}g$ treated group and its ratio in 60 and 90 ${\mu}g$ treated groups, filament length, weight and moth emergence percentage in all the treated groups and egg productivity in 90 ${\mu}g$ treated group were increased significantly. The remaining groups did not show any significant changes compared with that of carrier control.

• International Journal of Industrial Entomology and Biomaterials
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• v.2 no.1
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• pp.79-81
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• 2001

A study was conducted to establish the degree of genetic divergence between different hybrid forms and rearing conditions through estimation of the minimum number of genes (allelic pairs) differentiating parents in terms of specific quantitative traits. It was established that the minimum gene numbers differentiating parental lines in the inheritance of cocoon was 1, of cocoon shell weight- between 1 and 2, and of silk filament length- between 2 and 3. The variability in the specific genetic parameter could be explained by the reliability of the statistical-and-genetic method used and the expression of genes affecting the formation of each of the characters tested. Gene expression, in its turns is conditioned both by the gene interaction within the genotypes and the different genotype response to environmental change. To go deep in the problem, experiments should be conducted under strictly controlled conditions, reducing the mathematical-and-genetic analysis to a physiological levels and hence to analyse the genetic nature of the specific quantitative character formation and its genetic control.

• Journal of Sericultural and Entomological Science
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• v.7
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• pp.81-87
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• 1967

This report was prepared to find the causes of breaks during the winding operation and the obtained results were as followings. 1. Among around kinds of breaks, the percentage of breaks on the silk thread in our country was that injured and damaged thread was 43.23% where as hard gum spots of 16.07% split thread of 11.70%. and disturbed one of 7.22% were found. 2. It was known that the breaks percentage between Spring cocoon and Autumn cocoon bad the difference. 3. Microscopic observation of the spots of breaks were separately made, and the sccurted causes were observed to prevent the admajor defects.

• International Journal of Industrial Entomology and Biomaterials
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• v.3 no.2
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• pp.157-162
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• 2001

The effect of topical application with naphthoxyacetic acid on economic parameters was analyzed following treatment of fifth instar larvae. Larvae treated during the fifth instar showed significant increase in larval weight along with other enhanced larval, cocoon and adult parameters. The larval period was significantly shortened in all the treated groups with increased cocoon and shell weights in male and shell weight in female in 400 ${\mu}g$/ml treated group and filament length in all the treated groups. Fecundity increased significantly in dose dependent manner in all the treated groups, when compared to that of the carrier control group. This suggests that naphthoxyacetic acid, in addition to affecting larval growth, also affect silk production and reproductive performance.

• International Journal of Industrial Entomology and Biomaterials
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• v.1 no.1
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• pp.47-52
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• 2000

The effect of supplementation with potassium nitrate on economic parameters was analysed following treatment of last larval stadium. The treated larvae showed a significant increase in larval weight at 500$\mu\textrm{g}$/ml and silk gland weight in all the treated groups along with other enhanced larval, cocoon and adult parameters. The larval period was significantly decreased in all the treated groups with increased female and male cocoon weights its shell weights filament lengths at 500$\mu\textrm{g}$/ml. The denier was significantly decreased in all the groups. The filament weight moth emergence percentaged length of the ovariole were unaffected. However, eggs per ovariole, fecundity and hatching percentage significantly decreased compared with the corresponding parameters of the carrier control.

• International Journal of Industrial Entomology and Biomaterials
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• v.38 no.2
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• pp.51-55
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• 2019

The structure and properties of silk polymers (fibroin and sericin) can be satisfactorily controlled by choosing a suitable silkworm variety and, hence, this parameter (i.e., silkworm variety) has attracted increasing attention. A previous study reported that the crystallinity of white colored silkworm cocoons depends on the silkworm variety. In the present study, sixteen yellow colored silkworm variety cocoons were produced and their molecular conformation and crystallinity were investigated. The conformation of the silkworm cocoons varied with the silkworm variety. Most cocoons exhibited ${\beta}$-sheet conformation, although random coil and ${\beta}$-sheet conformations co-existed in some cocoons (e.g., 21 and D90). The crystallinity of the silkworm cocoons varied with the silkworm variety and the measurement position of the cocoon (i.e., outer surface or inner surface). However, the difference in the crystallinity indices of the outer and inner surfaces comprising the cocoons varied with the silkworm variety, but was <2% for all cocoons, except for MAL.

• Journal of Sericultural and Entomological Science
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• v.5
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• pp.25-38
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• 1965

I. Breeding of tussah silkworm(preliminary report). The preliminary examination for bleeding has been carried out since 1963 in tussah silkworms. 1) The strain(l-MG-B)of the heaviest silk quantity was the green silkworm and brown cocoon in univoltine, and the strains(2-G-B, 2-MG-B) of the heaviest silk quantity were also the green silkwom and brown cocoon in bivoltine in both spring and fall in 1965. 2) It looks like the voltinism, the body color and the cocoon color have reached to pure line up to 1965. II. Best place for the winter of tussah pupa. This work was aimed to find out good ways for the winter of tussah pupa. 1) The hatch of bivoltine was better than that of univoltine. 2) The cocoons covered with the leaves were good in the emergence of moth. 3) The cocoons which were kept at natural temperature till the first emergence of moths would show bad in both hatch and emergence. 4) If some of the pupae kept under natural condition were controled at proper temperature for a few days, hatch and laying eggs were best. 5) The best places for the winter were the egg storage and the rearing room. III. Relation between incubation temperature and voltinism. 1) When the tussah pupa are kept at natural temperature during winter, the moths do not come out of the pupa. 2) There is no difference between about 18$^{\circ}C$ and about 25$^{\circ}C$ during incubation in hatching ratio. 3) The tussah silkworms of univoltine in mortality are stronger than that of bivoltine. 4) There is not any relation between voltinism and high or low temperature for pupa and eggs. IV. Induced mutation by gamma-ray and neutron in tussah silkworm. This work was carried out in order to induce the mutation by treating the pupa or the eggs of tussah silkworm with gamma my and neutron. The results obtained are as follows. 1. Though the whole pupa treated with neutron become moths, the moths have no ability to copulate each other. The only moths emerged from pupa treated with neutron, 4000${\gamma}$ are able to lay all un-fertilized eggs, some of which have a hole on the surface and nothing of contents. 2. The non-diapause eggs are treated with neutron in spring, but the hatching ratio is 50∼60 percent, but the whole eggs treated with gamma ray are never hatched. 3. The sensitivity of the pupa to neutron is weaker than that of the eggs. 4. The hatching ratio is in direct proportion to the gamma ray dose. 5. Author find out a new mutant which is excellent in the cocoon quality, so he will do the progeny test next hear.

• Journal of Sericultural and Entomological Science
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• no.12
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• pp.37-45
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• 1970

The processing management forms of our country's filature factories in 1969 are summarized as follows. (1) About 80％ of total cocoon collection is made within 5 days involving peak day, and 10％ of cocoon collection is finished until 3 days before and after the peak day, (2) About 92％ of alive cocoons transported on unpaved road, and about 40％ of the cocoons purchased by all factories are loaded on trucks from common selling station which is far beyond 40km, therefore a new packing system of alive cocoons to drop the damage of cocoon qualities, should be taken. (3) 22％ of all factories in our. country have only low-temperature cocoon drying machine. Therefore the installment of hot-air cocoon drying machine is required urgently. (4) In view of cocoon qualities in our country, the grouping method of cocoon for reeling. taken by about 50％ of the factories at percent, which classify cocoons for reeling as high group (1,2,3,4 grades) and low group(5,6 grades), will have to be replaced by the method tat classify them high group (1,2 grades) middle group (3,4 grades), low group (5,6 grades). (5) The .ratio of cocoon assorting stood about 10％ in multi-ends reeling, about 15％ in automatic reeling, conclusively, the ratio of cocoon assorting for automatic reeling was higher tan that for multi-ends reeling. One person's ability for a day in cocoon assorting reaches to about 80-100kg. (6) Cocoon cooking condition requires the increase of the cooking time, the pressure and temperature used to be prolonged as much as the qualities of cocoons are material cocoon ior automatic and double cocoon machines are treated uncompletely. (7) Automatic silk reeling is being performed at 1-2$^{\circ}C$ lower in reeling water temperature and operated at about twice velocity. (8) The temperature and humidity of rereeling room stood at 25$^{\circ}C$, 67.2％ R.H and 32.3$^{\circ}C$, 51.9％ R.H of rereeling machine are showed, Average rereeling velocity is 233m/min and large reefs charged for one person are 7.5 reels and form of skein used in all factories is double skein. (9) About 73％ of water sources for filature used under-earth water. About 48％ of all filature factories in our country have not yet water purifying equipments. Installation of the equipment for these factories seems to be urgent, (10) Denier .balance, sizing reel, seriplane, are being used in most factories as self-inspection apparatus. (11) More than 90％ of the factories use the vacum tank in rereeling process and about 20％ of them use it in cocoon cooing process (12) Only 21％ of the factories use chemicals in filature process. About all them use "Seracol 100" in cocoon cooking process and "Seracol 500" in rereeling process, (13) Above survey results explain each all factories show large difference in the processing management. Therefore, it is believed that intercommunication through seminar or technical exchange will contribute to the production evaluation of cocoon in our filature industry.

• International Journal of Industrial Entomology and Biomaterials
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• v.3 no.1
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• pp.31-35
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• 2001

Ten newly evolved bivoltine hybrids of silkworm (Bombyx mori L) were evaluated with control hybrid KA${\pm}$NB4D2 during three seasons of a year for their seasonal performance. Analysis of variance and other statistical methods were employed and the performance was observed in respect of 10 quantitative traits. The results showed significant genotype${\pm}$environment interaction with respect to four quantitative characters viz. fecundity, yield/10,000 larvae, filament length and raw silk (%). Environmental effects were significant for nine characters out of ten characters evaluated. A 105${\pm}$J2 and B${\pm}$NB4D2 were considered as highly adaptable hybrids to local conditions with high mean for maximum characters studied and found suitable to rear in all seasons.