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Bahar M.H.,Khulna University | Bahar M.H.,University of New England of Australia | Al Parvez M.,Khulna University | Rahman S.,Bangladesh Sericulture Research and Training Institute | Islam R.,Khulna University
Entomological Research | Year: 2011

Five cultivated mulberry plant varieties, BSRM-34, BSRM-56, BSRM-57, BSRM-58 and BSRM-59, were used to evaluate the effects of plant variety on larval and cocoon characteristics of mulberry silkworm Bombyx mori L. Silkworm larvae undergo their entire larval periods on leaves of mulberry varieties. Different larval characteristics of larval weight, larval length and larval breadth were measured in different growth stages. After rearing, the fifth instar larvae were transferred into a mountage (Chandraki) structure for cocoon rearing for spinning and cocoon production. The cocoons were then harvested and different cocoon characteristics like cocoon weight, shell weight and shell percentage; and other characters like pupal weight and effective rate of rearing were measured. The results showed statistically significant differences among different varieties on larval and cocoon characteristics. The highest performance was observed by feeding the variety BSRM-34 in respect of the average weight of 10 mature larvae (40.5g), single mature larval length (7.6cm) and breadth (1.0cm), single cocoon weight (1.4g), shell weight (0.2g) and pupal weight (1.2g) while the average performance was recorded by feeding varieties BSRM-57 and BSRM-59. The poorest performance was showed by feeding the variety BSRM-56 (in case of larval characters) and BSRM-58 (in case of cocoon characteristics). These two varieties also showed the poorest performance for silk yield. Through comparing all the above parameters it was concluded that BSRM-34 is the best mulberry variety and it is recommended that Bangladeshi farmers adopt that variety for better yield of silk. © 2011 The Authors. Entomological Research © 2011 The Entomological Society of Korea and Blackwell Publishing Asia Pty Ltd.

Ali M.S.,Bangladesh Jute Research Institute | Rahman R.F.,Bangladesh Sericulture Research and Training Institute | Swapon A.H.,Bangabandhu Sheikh Mujibur Rahman Agricultural University
Journal of Insect Science | Year: 2015

Cuticular protein genes are good models to study the molecular mechanisms of signaling by ecdysteroids, which regulate molting and metamorphosis in insects. The present research demonstrates on hormonal regulation and analysis of the regulatory sequences and transcription factors important for Bombyx mori cuticular protein glycine-rich13 (CPG13) gene expression. Expression of CPG13 was strong at prepupal stage in wing tissues of B. mori. CPG13 expression was induced by the addition of 20E, which was inhibited by cycloheximide in the wing disc. The upstream region of the CPG13 gene was analyzed using a transient reporter assay with a gene gun system and identified two BR-Z2 binding sites to be important cis-acting elements for the transcription activation of the luciferase reporter gene by an ecdysone pulse. Site-directed mutagenesis of these sites, followed by introduction into wing discs, significantly decreased the reporter activity. It was found that the regions carrying the binding sites for the ecdysone-responsive transcription factor BR-Z2 were responsible for the hormonal enhancement of the reporter gene activity in wing discs. Mutation of the BR-Z2 binding sites decreased the reporter activity suggesting that the BR-Z2 isoform can bind to the upstream region of the cuticle protein gene, CPG13 and activates its expression. © The Author 2015. Published by Oxford University Press on behalf of the Entomological Society of America.

Rahman R.F.,Bangladesh Sericulture Research and Training Institute | Ali M.M.,Bangladesh Sericulture Research and Training Institute | Salam M.A.,Bangladesh Sericulture Research and Training Institute | Ara J.,Bangladesh Sericulture Research and Training Institute | And 2 more authors.
Journal of Biological Sciences | Year: 2015

Heterosis and combining ability studies of the isolated variable multivoltine races and developed bivoltine races with high yield capacity and their eighteen combinations were evaluated in two commercial rearing seasons in Bangladesh. Appropriate statistical methods were employed to interpret data on the hybrid performance, general and specific combining ability of the hybrids. Analysis of variance for combining ability revealed larger mean squares. Here high δ2gca/δ2sca values for most of the characters reflected predominant additive gene action. Similarly, the variance of components of specific combining ability (δ2sca) of multivoltine×bivoltine were higher than those of general combining ability (δ2gca) for most of the characters in both the seasons indicating preponderance of non-additive gene action inheritance of all these traits. Among the combinations BSR-BN(B1)×BSRB-BB1 and BSR-3×BSRB-BB2 exhibited highly productive performance which could be recommended for commercial cocoon production in Bangladesh. © 2015 Asian Network for Scientific Information.

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