Growth and Morphology of a Synthetic Channel Catfish (Ictalurus punctatus)-Blue Catfish (Ictalurus furcatus) Backcross Breed and the Hybrid Between the Backcross Female and Blue Catfish Male

Abstract

The F1 hybrid between a channel catfish female (Ictalurus punctatus) × a blue catfish (Ictalurus furcatus) outperforms both parental species in commercial environments for numerous traits. However, reproductive isolation mechanisms between the species make mass production of the F1 hybrid labor intensive and the hybrid is not 100% disease resistant. A synthetic breed be-tween channel catfish and blue catfish was produced by 3 generations of backcrossing with channel catfish followed by one generation of closed breeding. This synthetic channel-blue breed was hybridized with blue catfish males to determine if there could be benefits from both multiple generations of backcrossing followed by heterosis from hybridization. The growth of this hybrid was approximately 30% faster than both the parental synthetic backcross breed and that of chan-nel catfish. The growth rate of synthetic backcross catfish was similar to channel catfish which is not surprising as selection for growth rate was not part of the backcrossing program. The hybrid between the backcross female and blue catfish male had the highest relative body area than back-cross catfish and channel catfish, which predicts that it would also have the higher dressout and fillet percentage. The correlation among morphometric traits was variable among genotypes. Skewness for body weight tended to be low to moderate for all genetic types, which is important considering the oversized fish problem in the commercial industry. Skewness for relative body area was highly negative for the backcross × hybrid, negative for the backcross and positive, but near zero for the channel catfish.