Genetic analysis of silkworms (<i style="">Bombyx mori)</i> through RAPD markers

Abstract

389-395Mulberry silkworm, Bombyx mori L. is the most important insect being used for commercial extraction of silk in sericulture industry. To enhance the productivity and quality of silk fibers, many attempts are being made to improve the silkworm stocks through genetic manipulation. For that knowledge on the genetic diversity of the parental stocks is essential for selection and conservation of these precious materials. Keeping this in view, genetic diversity among twenty silkworm stocks differing in their yield potential and nature of voltinism was estimated through PCR amplification of the genomic DNA with 10 random amplified polymorphic DNA (RAPD) primers. A total of 68 bands were generated. Of which 61 were polymorphic (90%). The pair-wise genetic distance estimated from these bands varied from 0.058 to 0.513 with an average distance of 0.246. The cluster analysis using unweighted pair group using arithmetic average (UPGMA) grouped the silkworms into six groups and one isolate. Spatial distribution of the silkworms on two-dimensional figures using ALSCAL multidimensional scaling has broadly discriminated the multivoltine from the bivoltine silkworms. Certain silkworm stocks like Kalimpong-A, C’nichi, Nistari (P) and Mysore Princess were having higher genetic distance from others and, thus, could be used for heterosis breeding and also in breeding programs aimed at introgressing hardy genes into the bivoltine high yielding stocks