STUDIES ON THE COMBINING ABILITY AND HERITABILITY OF SOME QUANTITATIVE CHARACTERS OF BOMBYX MORIL.
Duan Jialong Department of sericulture
According to a 5×4 incomplete dillel mating design 9 strains of silkwormwere uqed to make 20 crosses (not including reciprocal crosses) to evaluate thecombining ability and heritability of 10 quantitative characters of silkworm inthig study. The main results are as follows: Variances of general combiningability (GCA) of 10 quantitative characters among each strain tested, as wellas those of special combining ability(SCA) of 9 characters among crosses wereall highly significant. The relative effect values of different characters in eachstrain were significant, so were those for different strains of each character.The ranges in GCA of characters among strains were different. It was foundthat each cross had different relative effects in different characters, and eachcharacters in different strains also had different relative effect values. TheSCA of different crosses showed a complex manner, however, it was possibleto evaluate the SCA of F1 crosses according to their parent's GCA. The cocoon shell weight. The cocoon shell percentage. the cocoon filamentlength, the number of eggs produced by one female had higher narrow senseof heritability (NSH), while the cocoon weight. the reelability. the length ofnon--broken cocoon filament. the cocoon filameut size, and the sensitivity toNPV had middle or lowor NSH. Moreover, The BSH of some characters weremuch higher than their NSH, it indicated that the nonadditive effects werestill significant.