برآورد آثار ژنی و وراثت‌پذیری صفات مرتبط با ابعاد پیله در کرم ابریشم

Domestic silkworm (Bombyx mori L.) is the most important silk cocoon producer. The cocoon of silkworm includes several recordable traits including cocoon dimensions traits. Due to the importance of cocoon size in buying and selling and spinning, cocoon dimensions could be among the target traits of silkworm breeding. In this study narrow sense heritability and gene effects of cocoon dimensions were estimated by using of diallel cross program and Griffing’s model I. Diallel mating design was between Chinese lines (108, 110, 114, 118) and Japanese lines (107, 109, 111, 113) in the form of 8×8 diallel cross which includes direct and reciprocal mating. The studied traits included cocoon length (female and male), cocoon width (female and male), cocoon length/ width ratio and number of cocoons per liter. The results showed that the mean square of general combining ability (GCA) was significant for male cocoon length (P<0.05) and also for the other traits (P<0.01). Specific combining ability (SCA) for all traits was significant (P<0.01) which these results showed the importance of both additive and non-additive effects in controlling of these traits. The significant effect of reciprocal mating was seen for male cocoon length and number of cocoons per liter (P<0.05) and also for the other traits (P<0.01) which consider as the result of maternal effect in controlling of these traits. The results showed that non-additive gene effects are more important than additive gene effects in the controlling of these traits except number of cocoons per liter. Therefore it seems that this trait has the potential of selection in silkworm lines. Thus selection methods can be used for improvement of this trait and for the other traits, cross breeding (hybridization) would be better. The narrow sense heritability for male cocoon length and number of cocoons per liter respectively was 0.008 and 0.15. For the other traits due to smaller mean square of GCA than SCA and estimation error, it could not be estimated.