The heterosis of F_1 hybrids (jian carp×huanghe carp) and path analysis of main growth traits

Comparison between the F1 hybrids(direct cross and reciprocal cross) of Jian carp(Cyprinus carpio L.),and Huanghe carp(Cyprinus carpio haematopterus) and Jian carp were made on the body length,body height,body weight,growth index,fullness,variation coefficient and super-parents heterosis.Growth equations were established and path analysis of main growth traits were conducted.The results showed that reciprocal cross F1had significant heterosis in terms of body length,body weight,and growth index owing to the fast growth and increment.But the high degree of variation coefficient suggested an intensive selection be needed.The highest fullness was observed in Jian carp all the time.There was higher super-parents heterosis rate on body length and body weight in reciprocal cross F1 hybrids than that in direct cross F1 hybrids.Path analysis revealed that body length and body height were closely related with body weight in offspring.The influence of body length on body weight was attributed to the direct effect while the influence of body height on body weight resulted from indirect effect.There was no difference between body length and body height effect in Jian carp.However,in F1 hybrids,the effect of body length was much higher than that of body height.The decisive coefficient of remnants was negligible,indicating that body length and body height had the decisive effect on weight increment.