Comparative study of biological and technological characters in three generations of silkworm Bombyx mori L. ameiotic parthenogenetically cloned lines

Purpose: Detect any deviation in biologic and technologic characters of eight ameiotic-parthenogenetically cloned lines of Bombyx mori L. from different origins from a normal sexually reproduced control line in three generations. Methods: Comparative study of the three generations was conducted in SES, Vratza, unit of the National Center for Agrarian Sciences of Bulgaria after fixing all environmental rearing conditions. Results: The ameiotic-parthen-clones displayed good parthenogenetic development, although total hatchability was significantly less than the sexually reproducing control populations. Survival rates between clones and control were not significantly different. All clones displayed significantly longer larval periods. Slight decline in second generation, and a steeper one in the third generation were observed for all eight cloned lines in cocoon weight, shell weight, and shell ratio and these differences were statistically significant. Cocoon yield was significantly lower than the control throughout the three generations. Conclusions: Our parthen-cloning method has a high rate of success in comparison to other cloning methods, the cloned progeny populations although were weaker technologically (cocoon weight, shell weight, and shell ratio), the biological characters (parthenogenetic development and survival rate) were not compromised. Further study is needed to determine the thermal needs of the cloned embryos and metabolic rate of all stages.