• International Journal of Industrial Entomology and Biomaterials
• /
• v.2 no.1
• /
• pp.79-81
• /
• 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
• /
• v.38 no.2
• /
• pp.138-143
• /
• 1996

Cooking of tasar silk cocoon of Deba variety (A. mylitta D.) with tartaric acid has been optimized by using an orthogonal central composite design. Shell weight loss and silk filament recovery are influenced by duration of treatment and acid concentration. Mechanical properties do not change with the process parameters. Hardness of water does not affect significantly the recovery of silk filament.

• Journal of Sericultural and Entomological Science
• /
• v.40 no.2
• /
• pp.150-157
• /
• 1998

This study was carried out to define the effects of anti-juvenile hormone analogue(AJH) treatment at different silkworm larval stages on some silk filament properties. It was revealed that the treatments at the 1st and 2nd days of the 3rd instar as well as the 1st day of the 4th instar resulted to trimolters induction without lethal effect. The trimolters induced by treatment at the 1st day of the 4th instar showed the shortest larval duration and the lowest single cocoon weight, cocoon shell ratio, cocoon size, single filament length and denier of filament compared with those of the control, while the trimolters induced by the 3rd-instar treatment showed intermediate values. All treatments showed no significant differences from the aspect fo degumming ratio, elongation rate and crystallinity index of fibroin. However the silk filament obtained from the treatment at the 1st day of the 4th instar showed the highest tenacity which was revealed to be related to the better uniformity of filament by the means of microscopic photographing. FT-IR spectroscopy of the silk fibroin showed a sharp and strong peak at the position of 794.72 cm-1 in all AJH-treated samples regardless of trimolters induction, which was absent in control.

• Journal of Sericultural and Entomological Science
• /
• v.49 no.1
• /
• pp.24-27
• /
• 2007

Silkworm fed on the mulberry leaf mixed with silver nanoparticle to produce silver-nanoparticle embedded cocoon. Comparative analysis of silver content of cocoon shell, percentage of pupation and percentage of cocoon-shell weight showed that the optimum concentration and the feeding period of mulberry leaf mixed with silver nanoparticle were 500 ppm and the period from 3 day 5 instar to mounting of silkworm. The silver content of cocoon was observed variously by silkworm breedings. C212 variety makes pale yellow cocoon with the highest silver content(69%). Using the scanning electron microscope, we showed that the size of silver nanoparticles in silk was observed from 26.98 to 99.81nm. Silver-nanoparticle embedded silk is expected to use as high valuable application owing to the different functional properties including antibiotic characteristics and mechanical and electronic properties. The applicable fields expected is antistatic and/or electronic products with biological degradable natural materials.

• Journal of Sericultural and Entomological Science
• /
• v.21 no.1
• /
• pp.46-49
• /
• 1979

These experiments were made in order to compare the productivity of various varieties of F$_1$silkworm eggs imported from foreign sericultural countries with the productivity of some F$_1$silkworm eggs varieties produced by Turkey. The results are summarized as follows: 1. In the durations of whole instar, it lasted 30∼38 days under natural rearing conditions but Jam 107${\times}$Jam 105 about 30 days. 2. Cocoon yield per case of silkworm eggs was shown significantly among the varieties. Thaiei ${\times}$ Choan was the highest yield of cocoon, followed by Isonzo, Piave, M-198, M${\times}$N, S${\times}$P, J${\times}$C and Jam 107${\times}$Jam 108 in that order. 3. In the percentage of cocoon shell, M-197 was the highest and other varieties were almost on the same level of cocoon shell, but Jam 107${\times}$ Jam 108 was the lowest percentage. 4. In the weight of a cocoon, Choan${\times}$Thaiei was the heaviest, followed by S${\times}$P, C${\times}$J, M${\times}$N, M-197, Piave, Livenzo and Jam 107${\times}$Jam 108 in that order. 5. In the raw silk percentage of fresh cocoon, Choan${\times}$Thaiei, 3 Italian varieties and Turkish M${\times}$N. C${\times}$J belonged to the first group of better raw silk percentage, followed Polish M-197 and Jam 107${\times}$1am 108 in that order.

• International Journal of Industrial Entomology and Biomaterials
• /
• v.19 no.2
• /
• pp.265-268
• /
• 2009

Wild silkmoths can be utilised sustainably in the production of silk as an income for resource-poor rural communities. However, attack by parasitoids and predators affect the quality of cocoons and quantity of raw silk produced. A laboratory experiment was undertaken to quantify the effect of parasitoids' (dipteran and hymenopteran) and predators' (ants) exit and ingress holes, respectively, on silk production. The mean number of shells required to produce fifty grams of raw silk was highest with cocoons parasitised by a dipteran and lowest with unattacked cocoons (but with moths already emerged). Degumming loss was highest in parasitised and lowest in unttacked cocoons, but both were not different from cocoons predated by ants. Shell weight was highest in unattacked cocoons, followed by hymenopteran-parasitised and predated cocoons, with the dipteran parasitized ones being the least. Single cocoon weight was greater in hymenopteran-parasitised and predated cocoons than the dipteran-parasitised and unattacked cocoons. Shell ratio or raw silk, floss and yarn weights were higher in unattacked than parasitised and predated cocoons. The total loss in raw silk attributable to attack by parasitoids and predators ranged between 17.4~31.2%. The results offer baseline information for assessment of economic losses in wild silk farming due to parasitoids and predators in the field.

• International Journal of Industrial Entomology and Biomaterials
• /
• v.10 no.2
• /
• pp.143-145
• /
• 2005

Lamerin breed of the silkworm, Bombyx mori L. for Northeastern India hosts a vertically transmitted microsporidian parasite for generations, which does not harm significantly the cocoon production. The transversally infected progenies do not exhibit marked external sign or symptom. The microspordian causes inapparent infection and over $(80\%)$ of the infected progeny survives and spin cocoons. There is possibility of co-existence between the breed and the associated micosporidian parasite. To evaluate the impact of the microsporidian on breed the present study was conducted in respect of tranovarial transmitted (observed as T1), secondarily infected (observed as T2) and healthy silkworm (observed as T3). The larval and pupal mortality was $12\%$ and $6\%$ in T1 and $10\%$ and $3\%$ in T2 batch, while in case of T3 batch there was no mortality. Significant changes were also observed in single cocoon weight, single shell weight, denier, reelibility, raw silk recovery $\%$ and neetness. There is no significant impact of the infection on the fecundity and hatchability. The hatchability of the eggs laid by healthy or infected moths are equall as much as control but the progeny had the infection transmitted from the parent.

• Journal of Sericultural and Entomological Science
• /
• v.49 no.2
• /
• pp.51-55
• /
• 2007

Investigation of atmospheric data and rearing results was conducted to analyze the effects of atmospheric factors such as temperature and precipitation on silkworm in 8 rearing places in which local adaptation test was being conducted with different mulberry growth condition, soil and atmosphere during spring and autumn rearing season of 2006. The atmospheric characteristics of spring rearing time are as follows. The average temperatures of young silkworm, old silkworm, mounting were $17.7^{\circ}C$, $19.8^{\circ}C$, $21.5^{\circ}C$ respectively, and $1^{\circ}C$ higher than normal year. The precipitation of young silkworm, old silkworm, mounting were 15.1 mm, 6.9 mm, 7.0 mm, respectively, and 22.9 mm lower than normal year in old silkworm and mounting. The daylight hours in larval stage was 1.7 hour shorter than normal year, but no difference in mounting. Thus precipitation was lower and temperature was higher than normal year in 2006. The rearing results of 2006 were 1 kg lower than normal year in cocoon yields per 10,000 3 rd molted larvae, single cocoon weight and cocoon shell percentage were a little higher. The atmospheric characteristics of spring rearing season are as follows. The average temperatures of young silkworm, old silkworm, mounting were $25.1^{\circ}C$, $20.5^{\circ}C$ and $19.9^{\circ}C$ respectively, temperature in young silkworm was $1^{\circ}C$ higher than normal year, and temperature in old silkworm was $1.3^{\circ}C$ lower than normal year. The precipitation of young silkworm, old silkworm, mounting were 110.2 mm, 4.6 mm, 3.7 mm, respectively and there were little differences compared to normal year. The atmospheric condition of 2006 which was similar to normal year did not affect the autumn rearing results of 2006. Namely, the single cocoon weight and cocoon shell weight were not different from normal year, and the same was cocoon shell percentage.

• Journal of Sericultural and Entomological Science
• /
• v.20 no.2
• /
• pp.26-31
• /
• 1978

The objective of the present study was to investigate the effect of nicotine-contaminated mulberry-leaf, which was grown in the vicinity of tobacco drying plant (TDP), on cocoon crop. Mulberry-leaf harvested from the field at Sericultural Experiment Station (SES), Suweon, Korea, was used as control, supposedly nicotine-free leaf. Leaf harvested from the field in the distances of 30-50m, 300-400m and 700-800m from TDP was fed during the whole larval stage of the silkworm at. SES. The effect of leaf in each treatment level on the quantitative characters of the silkworm was summarized as follows; 1. Larval duration from 4th instar on was significantly longer in the TDP-leaf treatments than for the control. 2. Duration of matured silkworm appearance became longer as the distance of the mulberry-field from TDP got shorter, because the larval duration and growth of the silkworm were not uniform in the TDP-leaf treatments. 3. Mortality rates during the late larval, cocoon spinning, and pupal stages were highest for the 30-50m leaf, especially mortality rates during the late larval and pupal stage were serious. 4. Pupation rate was lowest for the 30-50m leaf and those for the 300-400m and the 700-800m leaf were not significantly different from that of the control. 5. Nicotine damage to cocoon weight and cocoon shell weight was significant in each TDP-leaf level. Cocoon shell ratio was reduced at the same extent in each level, compared with the control. 6. The ratio among cocoon-classes was significantly different between treatments, compared with best-cocoon ratio of 87.1% for the control. Cocoons were not uniform for the 30-50m leaf, and those for the 300-400m and the 700-800m leaf were as almost uniform as those for the control. 7. Loss of fresh cocoon yield became greater as the distance of the mulberry-field from the TDP-got shorter. In conclusion, the critical distance of mulberry-field, which influences larval health, cocoon quality and yield, appeared to be 800m from the TDP. Such other factors as wind direction and topographic location may be involved in the critical distance. 8. From the present experiment, we could obtain only the effect of nicotine on the silkworm through digestive system, since the silkworm was raised at SES in Suweon. If the silkworm.. were raised in the vicinity of the TDP, poison effect of nicotine on the silkworm could beo expected through exoskeleton and tracheal system as well as through digestive system.

• International Journal of Industrial Entomology and Biomaterials
• /
• v.5 no.2
• /
• pp.175-182
• /
• 2002

A new high yielding mulberry genotype, Victory-1 (V-1) was recommended to the field for irrigated areas by Central Sericultural Research and Training Institute (CSRTI), Mysore during 1996-1997. As K-2 and S-36 mulberry genotypes are already in the field, a study on the comparative performance of V-1, 5-36 and K-2 varieties, in terms of leaf yield, yield attributes, leaf moisture and moisture retaining capacity and their impact on silkworm rearing was carried out under Telangana conditions of Andhra Pradesh during 1999-2001. Among the three genotypes the leaf yield was found to be significantly (P < 0.01) higher in V-1 (64,130 kg/ha/yr) followed by S-36 (44,064 kg/ha/yr) and K-2 (23,990 kg/ha/yr). The maximum leaf moisture was also observed in V-1 (71.84%) compared to S-36 (66.86%) and K-2 (64%). The moisture retaining ability was more in V-1 (70.17%) followed by S-36 (66.20%) and K-2 (60.08%). The yield attributes were found to be significantly (P < 0.01) enhanced in V-1 over S-36 and K-2. Silkworm rearing results (bioassay) indicated a significant (P < 0.01) reduction in larval duration and improvement in larval weight, effective rate of rearing by number and weight, single cocoon and shell weights and shell ratio in the silkworm lots fed on V-1 variety followed by S-36 and K-2. Hence, in this study, V-1 was found to be superior among the three varieties studied.