Characters of Different Growth Stage on the F1 Progeny of 33 Full Diallel cross in Common Carp (Cyprinus carpio L.)

Jian carp (Cyprinus carpio var. jian) examined and approved in 1990, was the first approved aquatic specie using integrated genetic breeding technology. Jian carp is a good stock of cultivated fish species which has good growth traits and good disease-resisitant performance. Although Jian carp has been disseminated wildly, there still has a great need to enhance fine growth performance through continuous selection and genetic improvement. Huanghe carp is a remarkable local specie of common carp in northern China, which possesses good meat quality, strong cold resistance and high efficiency of food conversion. Heilongjiang carp has high frigid resistance, good quality and growth trait. Specific hybridization is an effective pathway for growth improvement in common carp breeding programs. In most cases, obvious heterosis may be observed in hybrids in growth rate, compared to their parents, suggesting a potential resolution to current problems. Generally, the growth pattern of hybrids and their parental species usually reflect that the hybrids were viable and whether superior performances over the mid parent values occurred or not. Covariance component defined for estimated breeding value play a central role in selection of best model for carp improvement by cross breeding and family selection. To explore the changes of growth traits in different F1 combination and different growth stage, the article illustrated the growth variation of 3*3 full diallel cross F1 based on the Jian carp, Huanghe carp and Heilongjiang carp by combination analysis, gender in combination analysis, gender analysis, bodyweight and weight gain in different stage analysis. At this time, the factors which may play an important role in the growth stages were also focused on by covariance analysis. The results showed that significant differences of body weight in different growth stage were found; both within and without considering the combination effect, different gender in the same stage had different growth performance. After 5 month PIT tagging, Jj purebred group had better bodyweight compared to other groups. But, the higher body weight and better body weight gain, which were due to cross, were got and the heterosis were also found. At the same time, 300 g gain for body weight after 17 months by PIT tagging between female and male was found. Whatever for first stage and for the second stage, female had bigger body weight gain than male had. LSmeans of body weight for 17 months PIT tagged fish in one combination based on the different covariance parameters, while estimated extreme value was observed in different combination for the specialized covariance component. Besides these, female had the higher body weight compared to the male except for the thickness of PIT tagged fish for 17 months as covariance parameter. These illustrated that covariance selection play a key role of in combination selection and breeding program. Further more, thickness of PIT tagged fish for 17 months as covariance component may produce the difference to separate female from the mixed group. Besides these, heterosis researched for specified combination was developed for special stage; sex selection in early stage can improve the economic effects; female had an advantage in body weight gain comparing male, especially in the crossbred combination. So, the economic traits of breeding program require considering the combination, growth period, gender effects and their interactions.