Abstract

                                Studies on longterm egg preservation schedule from 180 days to 300 days were taken up with 20 germplasm accessions of mutant silkworm genetic stocks of Bombyx mori L. Among 20 germplasm accessions 19 performed well in hatching trials (above 80%) and one accession (BBE-0313) showed less hatching (below 50%). Better hatching accessions were tested for rearing performance. Statistical analyses of the data collected in three trials revealed no significant changes in the quantitative characters (fecundity, hatching percentage, single cocoon weight and shell ratio and less significant changes in few accessions for some quantitative traits (larval weight, pupation rate and single shell weight of the genetic stocks between treatment (10 month egg preservation) and control (6 month egg preservation) except for total larval duration where there was no significant difference between control and treatment batches for all the 19 mutant accessions tested. The results indicate that extended schedule of 10 month egg preservation can safely be adopted for 19 accessions, which will reduce the cost of conservation and minimize the genetic erosion leading to reduced crop cycle.

Key words : Silkworm, Bombyx mori, mutants, genetic stocks, cold preservation, hibernation schedule, genetic erosion, conservation, crop cycles.