• Journal of Sericultural and Entomological Science
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• v.30 no.1
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• pp.8-19
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• 1988

The objective of the present study was to investigate the behavioral responses of sillkworm (Bombyx mori) larvae to: the dominant effect of walking distace: and the relationships between walking distance and the various economic characters on yellow sheets. The means of walking distances of progeny from F2 and F1 F1 and F2 generations, which was a hybrid between the long and the short walking distances, were shorter than those of parents. This may indicate that the genes for the short walking distances were partially dominant over those for the longwalking. Estimated broad sense heritability of larval walking distance was different for each larval instar, which fell into the range of 52∼84%. Genetic correlation was apparent between walking distances of all larval stages and some economic characters. The number of cocoons per liter and the period from incubation to emergence have shown the positive genetic correlation with walking distances. The cocoon yield, the sing cocoon weight, and the cocoon shell weight have shown to be in the negative correlation with walking distances. No correlation was observed between walking distances of the mature larvae and any economic characters. The analysis by the path coefficient showed negative direct effect of walking distances on the cocoon yield, and positive indirect effect on the single cocoon weight and the cocoon shell weight.

• International Journal of Industrial Entomology and Biomaterials
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• v.31 no.2
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• pp.127-131
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• 2015

Oak silkworm, Antheraea yamamai (A. yamamai), has been used for clothing and surgical suture and considered as biomaterial due to RGD tripeptide. This paper reported the degumming conditions of A. yamamai using sodium oleate, high pressure and temperature, and sodium carbonate. Degumming ratio of A. yamamai cocoon using sodium oleate was less than 10%. High pressure and temperature treatment induced 30% weight loss of A. yamamai cocoon. The concentration, treatment temperature and time using sodium carbonate was examined and revealed the following conditions for degumming; 5% owf, 60 min at 100℃. The degummed solution was confirmed using UV and FT-IR spectrometer. Our results can be used to handle A. yamamai silkworm cocoon for further application including material processing.

• International Journal of Industrial Entomology and Biomaterials
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• v.22 no.2
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• pp.45-49
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• 2011

The performance of five newly evolved cross breeds were evaluated across seasons to understand the genotype and environment interactions and their stability under fluctuating tropical environmental conditions along with control hybrids $PM{\times}CSR2$ and $APM1{\times}APS8$. The data was collected on eight economic traits namely fecundity, yield per 10,000 larvae by number, yield per 10,000 larvae by weight, survival rate, cocoon weight, cocoon shell weight, cocoon shell ratio and filament length. The data was subjected for Analysis of Variance (ANOVA) and relevant statistical methods. The performance data obtained was further subjected for multiple trait evaluation index method. The ranks were adjudicated based on the index values. The two hybrids viz., $MSO3{\times}APS45$ and $MSO1{\times}APS12$ performed well under diversified environmental conditions indicating their overall stability and superiority. These hybrids revealed highly significant (p < 0.01) improvement for the majority of the traits over the control hybrids.

• International Journal of Industrial Entomology and Biomaterials
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• v.3 no.1
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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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• v.2 no.1
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• pp.69-74
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• 2001

The effect of topical application with androstenedione on economic parameters was analyzed following treatment of last larval stadium. The treated larvae showed significantly increased larval weight along with other enhanced larval, cocoon and adult parameters. The larval period was significantly shortened in all the treated groups with increased cocooning percentages cocoon weight and its shell weight in female and filament length, weight and denier in all the treated groups. Hatching percentage increased significantly in dose dependent manner in all the treated groups when compared with the corresponding parameters of the carrier control group. This suggests that androstenedione can be used effectively for commercial silkworm rearing.

• Journal of Sericultural and Entomological Science
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• v.14 no.2
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• pp.61-65
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• 1972

The main purpose of this experiment is to select the best combining ability among KC${\times}$N13, and C20${\times}$N13 in view of the cocoon shell weight in Bombyx mori. In the spring of 1972, the author raised silkworms which were born from the crossing of the Chinese strain KC, C14, C20(female) with japanese strain N13 (male). Among each combining of crosses, the heritability of the cocoon shell weight was estimated by the method of variance analysis. The result of the experiment may he summarized as fellow; 1. For KC${\times}$N13 The cocoon shell was heavier than other combining crosses, but its heritability was lower than the others. The heritability of male moth was higher than that of female. 3. For C14${\times}$N13 The cocoon shell and the heritability was in medium value among the combining crosses, and the heritability of female moth was higher than that of male. 3. For C20${\times}$N13 The cocoon shell weigt was lower than the others, but its heritability was higher than that of others. In these combining crosses, C20${\times}$N13 is selected as a new race, which is much better than the commercial one, 103${\times}$104.

• International Journal of Industrial Entomology and Biomaterials
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• v.9 no.2
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• pp.199-205
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• 2004

With the main objective to know the feasibility of exploitation of F$_1$ hybrids in semi arid and arid climatic conditions of India, the present study was carried out by utilising RD$_1$ as female parent and six bivoltine silkworm breeds viz., CSR$_2$, CSR$_4$, CSR$_{5}$, CSR$_{17}$, CSR$_{18}$ and CSR$_{19}$ along with NB$_4$D$_2$ as male parents. Different hybrids exhibited their superiority for various economic characters during different seasons. Among F$_1$ hybrids, RD$_1$${\times}$CSR$_{5}$ was adjudicated as the best hybrid in terms of expression of significant positive hybrid vigour over mid parental value for five economic characters namely hatching %, cocoon yield, cocoon weight, cocoon shell weight and filament size, highest multiple trait average evaluation index value of 56.77 and comparatively uniform cocoon size with coefficient of variation (CV%) of 3.80 and Standard Deviation (SD) of 7.99 during September - October 2003. Results of the present study revealed that the F$_1$ hybrid RD$_1$${\times}$CSR$_{5}$ can be successfully exploited on commercial in semi arid and arid climatic conditions in India. India.dia.

• Journal of Sericultural and Entomological Science
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• v.32 no.1
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• pp.17-30
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• 1990

A 6${\times}$4 top-cross set was made from the ten silkworm parental lines selected by the first principal component scores. They were also analysed for the relationship between the combining ability and the first principal component score. The highest general combining ability effects were detected in the parental lines of Japanese, N39 and chinese, C46, for the most quantitative characters in the study. The first principal component score of factors related to silk productivity in the parents was significantly and positively correlated to the general combining ability of the twelve characters such as cocoon yield, cocoon weight, cocoon shell weight, cocoon shell percentage, duration of the 5th instar larvae, total larval period, length of a bave, weight of a have, non-breaking length of a bave, non-breaking weight of a have, raw silk percentage, and neatness. Similarity distance (D$^2$) was related to the specific combining ability of the characters such as cocoon yield, non-breaking length of a bave, non-breaking weight of a have, non-breaking ratio of a bave, raw silk percentage, neatness. From the results, it is possible to predict the general combining ability effects by the principal component scores for the 12 characters of the parents related to silk productivity.

• Journal of Sericultural and Entomological Science
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• v.17 no.2
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• pp.141-149
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• 1975

Silkworm is known to be damaged under the unfavorable environmental conditions. Recently, it has been often argued that nicotine is a main factor to affect the silkworm nutritional balance and to result in decrease of quantitative characters, and unbalance of larval nutrition. Especially in spring season, there is tendency to produce nicotine damage to silkworm fed with the mulberry leaf near to tobacco field early cultivated in mulching system. In these connections, the trial was made in the different pots placing by the different distance 10rn, 20m, 40m, and 60m in the direction of east-north from the tobacco field. Location of pot near to the tobacco fold is 40m below the tobacco Held and gradually higher than the tobacco field by 10 degree of slope. In addition, when the mulberry field is divided into two areas from the east-south to west-north, southern east zone is lowering down below 10 degree of slope and has 36％ of east-south wind, 21％ of south-east wind and 16％ of south wind, etc. Pots are left on the mulberry field from the completion of lower part leaf harvest to just before upper part leaf harvest is completed for 32 days. Then silkworm at 4th-5th stage was fed with the leaf grown during the period and larval characters are statistically analyzed. The results are summarized as follows： 1. 10-40m distant pot statistically at the same level has the longest larval duration and 60m distant pot is. not significant at 5％ level. Whole larval duration has same tendency as in the 5th larval duration. 2. Percentage of delayed molting larvae at the 5th stage is increased in 10m distant pot and there is no significance statistically in other pots, as compared with that of control. 3. It is not showed that there is no damage to mortality of the old larvae in 60m distant pot. 4. 10-20m distant pot produces a low pupation and others are at the same level statistically at 5％ significance, 5. It is showed that nicotine damage is occurred in single cocoon freight and cocoon shell weight up to 60m distant pot, rather higher damage in cocoon shell weight than in single cocoon weight. 6. It is showed that cocoon yield from 10, 000 molted larvae including double cocoon is decreased up to 40m distant pot far from the tobacco field in which 40％ of cocoon yield in 10m distant pot by 7kg, 26％ of cocoon yield in 20m distant pot by 3.9kg, 24％ of cocoon yield in 40m distant pot by 3.6kg, and 12％ of cocoon yield in 60m distant pot by 1.8kg, as compared with control. However, there is no significance statistically at 5％ level in 60m distant pot. With these above results, it is concluded that nicotine da mage could be occurred in cocoon yield and cocoon quality up to 60m distant far from the tobacco field.

• International Journal of Industrial Entomology and Biomaterials
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• v.46 no.1
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• pp.1-8
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• 2023

Mulberry (Morus spp.) production is a vital activity in sericulture along with rearing of silkworms (Bombyx mori L.) for silk production. The Sericulture Research and Development Institute (SRDI) conducted a study that evaluated 11 mulberry varieties, including nine newly-evolved mulberry hybrids and two check varieties. These mulberry varieties were fed to silkworm hybrid, DMMMSU 115 x 100. The rearing performance of DMMMSU 115 x 100 was determined based on the silkworm economic traits such as weight of 10 matured larvae, cocoon weight, shell weight, shell percentage, cocoon yield, reelability percentage, filament length and filament size. Six silkworm rearing trials were conducted with 50 silkworm larvae per treatment in three replicates. The data were analyzed in a one-way Analysis of Variance. Significant differences were tested further using Tukey's Honest Significant Difference. Mulberry varieties that garnered an evaluation index value of higher than 50 were identified and selected. Results of the study revealed significant variations among the mulberry varieties based on the parameters gathered except on the reelability of cocoons, filament length and size. Matured silkworm larvae fed with Alf 55 were significantly heavier and higher cocoon yield compared to those fed with Alfonso and S₅₄. Alf 32, Alf 55, Alf 58, Bat 37 and Bat 73 were identified as potential varieties and highly recommended as feed for the silkworm hybrid, DMMMSU 115 x DMMMSU 100.