Isoenzyme Polymorphism Of Silkworm Bombyx Mori L., 1758 (Lepidoptera: Bombycidae) Breeds From Germplasm Resources Of Bulgaria

Polyacrilamide gel electrophoresis (PAGE) was used to study the isoenzyme polymorphism of nonspecific esterases (EST), malate dehydrogenase (MDH) and acid phosphatase (ACP) from haemolymph, phosphoglucomutase (PGM) and hexokinase (HK) from silk glands and alkaline phosphatase (ALP) from midgut of mulberry silkworm (Bombyx mori L.). Genetic variations within and among five breeds kept in Bulgaria were found out. A total of seven polymorphic loci with 19 alleles were established. The observed polymorphism demonstrated breeds specificity. Inter-breeds differences regarding the degree of polymorphism and heterozygosity were established, too. The degree of polymorphism ranged from 77.80% to 11.10%. Low levels of observed heterozygosity and deviations from Hardy-Weinberg equilibrium in the most of analysed loci were found. The dendrogram constructed with the values of genetic distance showed that Hebar 2 formed one main cluster, while the rest breeds studied formed the other one. The results of the present study complement the data on the genetic heterogeneity of breeds from the silkworm genetic resources of Bulgaria and could help the breeders in the process to identify suitable parents for the breeding programs for yield improvement.