Silkworm genotypes were clustered into two groups, one consisting of six diapausing and the other of seven nondiapausing genotypes. RAPD technique could be used as a powerful tool to generate genetic markers that are linked to traits of interest in the silkworm.
The RAPD based dendrogram resulted in a clear separation of two groups, one comprising diapausing and the other nondiapausing genotypes. The clustering pattern of RFLP obtained was comparable to the phenogram resulting from RAPD analysis.
Detailed analysis of silkworm strains with microsatellite loci revealed a number of alleles ranging from 3 to 17 with heterozygosity values of 0.66–0.90. Along with strain specific microsatellite markers, diapause and nondiapause strain-specific alleles were also identified
The average heterozygosity value for each SSR locus ranged from 0 to 0.60, and the highest one was 0.96 (Fl0516 in 4013). The mean polymorphism index content (PIC) was 0.66 (range of 0.12–0.89). SSR markers are an efficient tool for fingerprinting cultivars and conducting genetic-diversity studies in the silkworm
The genetic distances between the clusters and within the clusters estimated 6 percent variability between the 4 races and Nistari. RAPDs are very efficient in the estimation of genetic diversity in populations that are closely related and acclimatized to local environmental conditions.
The mean polymorphism index content was 0.71 (range of 0.299–0.919). UPGMA cluster analysis of Nei's genetic distance grouped silkworm strains based on their origin.
Higher degree of genetic similarity within Japanese commercial lines than the Iranian native strains. The distinct clustering of these two sets of strains and lines reflects differences of the geographical origin and morphological, qualitative, and quantitative traits associated with them.
The genetic similarity estimated within and among silkworms could be explained by the pedigrees, historical and geographical distribution of the strains, effective population size, inbreeding rate, selection intensity, and gene flow.
The genetic diversity in studying strains was moderately low. Estimates of gene diversity in populations were higher in total (Ht) as compared to those within population diversity (Hs).
In selected mutant genetic stocks, the average number of observed alleles was , effective alleles , and genetic diversity (Ht) . ISSR is a valuable method for determining the genetic variability among mutant silkworm strains.
PCA analysis helped to visualize the two major clusters which included the multivoltines and bivoltines separately. The grouping of bivoltines in the PCA analysis clearly showed higher similarity among bivoltines as compared to the multivoltines.
The heterozygosity generated by the seven pairs of SSR primers varied from 0.098 to 0.396. Considerable genetic diversity is present among the 13 silkworm genotypes.
At the species level, A. pernyi and B. mori showed high levels of genetic diversity, whereas S. cynthia ricini showed low level of genetic diversity. However, at the strain level, A. pernyi had relatively the highest genetic diversity and B. mori had the lowest genetic diversity.
Multivoltine silkworm races are genetically more distant than the two bivoltine silkworm. Genetic distances among the multivoltine and bivoltine silkworm were 0.52 and 0.27, respectively.
Sufficient polymorphism and genetic diversity observed. The genotypes were grouped based on voltinism and subdivided based on cocoon shape and cocoon colour.
