Assessment of genetic diversity in the tropical mulberry Silkworm (Bombyx mori L.) with mtDNA-SSCP and SSR markers

Genetic diversity among 13 tropical nondiapausing silkworm (Bombyx mori L.) genotypes was estimated with simple sequence repeats (SSRs) and mitochondrial DNA (mtDNA)- single strand conformation polymorphism (SSCP) markers. Seven SSR primers from silkworm genome and the eight mtDNA primers from the conserved regions of 16S and 12S ribosomal RNA, cytochrome oxidase I, II and III, and cytochrome B revealed considerable genetic distance among the 13 silkworm genotypes. The heterozygosity generated by the seven pairs of SSR primers varied from 0.098 to 0.396. The eight pairs of mtDNA primers developed 2 to 10 haplotypes per primer sets. The dendrogram from these markers grouped the silkworm genotypes into different groups, from which potential parents could be selected for developing hybrids for commercial exploitations. Based on cocoon characters and the genetic diversity analysis, Kollegal Jawan was identified as a parent that can be crossed with either BL-23 or Mysore Princess for developing high yielding silkworms to rear commercially during summer and rain seasons.