• International Journal of Industrial Entomology and Biomaterials
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• v.3 no.2
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• pp.149-152
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• 2001

Effect of topical application with 10, 20 and 30 ${\mu}g$/ml testosterone propionate and estradiol -17${\beta}$ on the fourth and fifth instar bivoltine NB18 silkworm larvae Bombyx mori, on the glycogen and protein contents of the Fat body and trehalose and protein contents of the haemolymph has been studied. Glycogen content of the fat body was significantly decreased in both testosterone propionate and estradiol -17${\beta}$ treatment groups except in the group treated with 30 ${\mu}g$ testosterone propionate where the increase was not significant when compared with those of carrier controls. The increase/decrease in haemolymph trehalose content did not show any significant difference in all the treated groups. Protein content of the fat body significantly increased in 10 and 20 mg testosterone propionate and estradiol -l7${\beta}$ treated groups but in 30 mg treated groups the increase was not significant when compared with those of carrier controls. There was no significant change in the haemolymph protein content in all the testosterone propionate and estradiol -17${\beta}$ treated groups except in group treated with 10 ${\mu}g$ estradiol -17${\beta}$ where it showed a significant decrease when compared with that of carrier control.

• Journal of Sericultural and Entomological Science
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• v.40 no.1
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• pp.27-32
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• 1998

One indigenous polyvoltine strain (Nistari) and two bivoltine strains viz. P5 and NB18 along with one bivoltine hybrid (P5$\times$NB18) were subjected for studies on the differences on some physiologically important biomolecules like protein, nucleic acids and cholesterol. Ovarian protein and RNA content remained significantly high in the bivoltine races and their hybrid over multivoltine breed, while, DNA and cholesterol content remained significantly low in all the breeds and the hybrid as compared to Nistari strain. However, the ovarian weight was higher in both the bivoltine breeds and their hybrid than that of Nistari. Higher ovarian weight together with more protein and RNA concentrations reflect the preparatory phase for production of diapausing eggs by the bivoltine silknoths and their hybrid. The variations in biochemical parameters studied herein, thus establish a distinct difference in the overt reproductive physioiogy between multivoltine and bivoltine silkworms.

• International Journal of Industrial Entomology and Biomaterials
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• v.25 no.2
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• pp.171-174
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• 2012

In order to study the feasibility of utilizing bivoltine foundation cross (FC2) males of the silkworm as male components with Pure Mysore (PM), six foundation crosses viz,CSR2 x CSR27, CSR27 x CSR2, CSR27 x CSR50, CSR50 x CSR27, CSR2 x CSR50 and CSR50 x CSR2 along with CSR2 pure breed were assessed for performance of parental crop,grainage, rearing and reeling performance. The foundation crosses exhibited better performance than CSR2 as a parental crop and male component which resulted in higher egg recovery. Though there was not much difference between PM crossed with FC2 and CSR2 males pertaining to important bioassay parameters, PM x CSR2 exhibited superiority in reeling traits particularly with reelability and raw silk %. This study reveals that FC2 seed cocoons can be utilized during exigency when there is a dearth for CSR2 seed cocoons but not regularly.

• International Journal of Industrial Entomology and Biomaterials
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• v.14 no.1
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• pp.63-68
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• 2007

The response of silkworm, Bombyx mori L. to phytoecdysteroid (PE) when administered at different ages of $5^{th}$ instar was studied in the popular bivoltine ($CSR2{\times}CSR4$) and multi${\times}$bivoltine ($PM{\times}CSR2$) silkworm hybrids, reared on the Victory-1 variety of mulberry leaves. PE was administered to $5^{th}$ instar silkworm per os at a rate of $250{\mu}g$ per 100 larvae to different batches of silkworm at 0, 24, 48, 72, 96, 120, 144 hrs and at the onset of cocoon spinning when a few larvae were ripe. The larval and mounting duration, cocoon yield and cocoon characters were influenced by PE. The intensity of influence was dependent on the time of application. The larvae treated at the beginning of the instar, improved the economic traits significantly with a marginal increase in larval duration. In the larvae treated at the middle of the instar, larval duration was shortened remarkably but the economic traits were adversely affected. This particular treatment can become a good management strategy in the case of mulberry leaf shortage or disease incidence. In the larvae treated at the onset of cocoon spinning, the mounting duration was substantially reduced without much effect on the cocoon traits which would be a big benefit in commercial sericulture. The physiological significance of varied response of silkworm to PE administration is discussed.

• International Journal of Industrial Entomology and Biomaterials
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• v.7 no.1
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• pp.15-20
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• 2003

The present investigation was carried out to study the possible cause for reciprocal difference in silkworm hybrids. By utilising the polyvoltine race Pure Mysore (PM) and newly evolved breeds (CSR2, CSR5, CSR16 and CSR17), the direct and reciprocal crosses of polyvoltine ${\times}$ bivoltine and also bivoltine hybrids were studied. The hybrids of polyvoltine ${\times}$ bivoltine (direct) are superior to their reciprocal crosses in respect of cocoon yield, cocoon weight and filament length. The reciprocal crosses of polyvoltine ${\times}$ bivoltine are superior to their direct crosses in respect of fecundity and short larval duration. No significant differences were observed in the characters like cocoon shell ratio, raw silk percentage, denier, reelability and neatness in both polyvoltine ${\times}$ bivoltine direct crosses and their reciprocals. The expression of cocoon characters as a function of sex revealed that direct crosses (polyvoltine ${\times}$ bivoltine) showed higher cocoon weight, pupal weight, shell weight and longer filament length in females than the reciprocal crosses (bivoltine ${\times}$ polyvoltine), where as these characters in males were almost the same in both direct and reciprocal crosses, indicating that the sex-linked genetic factor played a more important role. it was clear that difference in cocoon yield observed in reciprocal crosses of polyvoltine ${\times}$ bivoltine was due to the low cocoon and shell weight in females which was turn due to presence of early maturity genes (Lme) linked with sex-chromosome (X) which effect on larvae period of the silkworm. In bivoltine hybrids, i.e., both direct and their reciprocals crosses, all the characters viz., hatching percentage, larval duration, survival, cocoon weight, cocoon shell weight, cocoon shell ratio, raw silk percentage, filament length, denier, reelability and neatness did not show any significant difference (except number of eggs laid by moth) which could account for presence of same maturity genes (Lm) in both direct and reciprocal crosses. it was clear that reciprocal differences occur when the hybrids are prepared from the parental strains with different voltinism.

• 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.

• International Journal of Industrial Entomology and Biomaterials
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• v.7 no.2
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• pp.191-195
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• 2003

The impact of antibiotic (Norfloxacin) administration ,at different concentration (50 ppm and 100 ppm) on commercial characters of bivoltine $({CSR_2}{\times}{CR_4})$ and the cross breed race $({BL_67}{\times}{CSR_101})$ was studied. The result indicated that antibiotic administration with different concentrations significantly improved the rearing and cocoon parameters like larval duration, larval weight, growth index, single cocoon weight, single shell weight and shell ratio. The post cocoon parameters like average filament length, non-breakable filament length, raw silk percentage, raw silk recovery percentage, denier, reelability and neatness were recorded significantly higher in antibiotic treated batches. The better performances of these parameters were recorded with the increase of antibiotic concentration.

• Proceedings of the Korean Society of Sericultural Science Conference
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• 2002.10a
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• pp.44-44
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• 2002

No Abstract, See Full Text

• International Journal of Industrial Entomology and Biomaterials
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• v.16 no.1
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• pp.15-20
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• 2008

Under the all India programme of evaluation of mulberry and silkworm genotypes, twelve bivoltine silkworm breeds obtained from Central Silkworm Germplasm Resource Centre, Hosur (CSGRC) were evaluated at the bivoltine silkworm breeding laboratory, Central Sericultural Research & Training Institute, Mysore (CSR&TI). These breeds were tested during September-October 2003, August-September 2004 and February-March 2005. The average temperature and humidity during September-October 2003 was $26.5^{\circ}C$ and 72.6% RH, while during August-September 2004, it was $26.5^{\circ}C$ and 75.2% RH and during February-March 2005 it was $24^{\circ}C$ and 48% RH respectively. The performance of the breeds in respect of 21 traits was studied and statistically analyzed using analysis of variance (Singh and Choudhary, 1985). Silkworm breeds were short-listed using multiple trait evaluation index method as suggested by Mano et at., (1993). Evaluation Index values were calculated for all the 11 traits of economic importance and six breeds were short-listed based on average index value 50 and above 50. Two breed viz., BV 183 (SMGS-1) have recorded average E.I. >50 in 10 traits (except in neatness) and ranked first and the breed BV 262 (SMGS9) with E.I. value >50 in nine traits except in cocoon weight and neatness ranked second, in the order of merit. These two breeds may be selected as resource material for evolving region specific silkworm breeds.

• International Journal of Industrial Entomology and Biomaterials
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• v.20 no.2
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• pp.79-85
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• 2010

Eight bivoltine inbred lines of silkworm Bombyx mori L. viz., AP8, AP10, AP17 and AP18 with marked female and plain male larvae and AP1, AP54, AP71 and AP72 with all plain larvae synthesized from Chinese commercial hybrids were evaluated for their general combining ability (gca), specific combining ability (sca) and reciprocal effects for eight quantitative traits. The line AP18 was found to be best general combiner by virtue of significant positive and positive gca effects for seven out of eight traits studied followed by the lines AP10, AP8 and AP17. Seven hybrids recorded significant positive and positive sca effects for all the traits under study reflecting the interaction of alleles, additive and non additive gene action and dominant effects expressed by genes. Among the 28 reciprocal hybrids, AP54$\times$AP18 and AP1$\times$AP17 revealed significant reciprocal effects for the six traits followed by AP54$\times$AP8 for five and AP10$\times$AP71 for four traits.