الفهرس 
INTRODUCTIONOnly 14 pages are availabe for public view
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Abstract
The final goal of most breedingprograms is to improve economic traits and to increase the ability of production in Bombyx mori, L. in order to increase the profit of silk producers and other sections of sericulture industry.
Methods & Results:
Crossbreeding in silkworm races or pure lines is a major approach for improvement of economically important traits.
applying a half diallel crossing design of four univoltine local entries coded P1, P2, P3 and P4 obtained from the stocks of the Sericulture Research Department of Plant Protection Research Institute- Agricultural Research Center to produce best hybrids.
Thirteen quantitative parameters i.e. fresh cocoon traits
The present study was carried out during Spring 2007 up to Spring 2010 under the laboratory conditions at Mansoura University, Faculty of Agriculture.
Generally, it could be concluded that differences were observed between the four entries for cocoon traits. The four entries acquired large degree of homogeneity for cocoon weight, cocoon shell weight, cocoon shell ratio and pupal weight and fecundity.
Selection would be more effective for these traits. While selection for fertility, hatchability percentage and larval duration were ineffective because these traits recorded low values of heritability.
Ratio of general combining ability genetic variance (GCA) δ2g and specific combining ability genetic variance (SCA) δ2s indicated that non-additive gene action is important for all traits under study.
Effects of general combining ability (GCA) revealed that no entry was good combiner for all traits. Also, effects of specific combining ability exhibited that no single hybrid have a best value for all traits.
Conclusion:
It could be concluded that no hybrid collected all the desired parameters under study. However hybrid P1xP2 gathered eleven traits and hybrid P1xP3 acquired four traits and hybrid P3xP4 gathered two traits.