General and specific combining ability of male blue catfish (Ictalurus furcatus) and female channel catfish (Ictalurus punctatus) for growth and carcass yield of their F1 hybrid progeny

• A factorial mating was used to estimate combining ability for hybrid catfish performance.
• Genetic effects for hybrid progeny traits were primarily additive.
• Maternal effects were substantial for hybrid progeny traits.
• Information will help guide breeding programs for hybrid catfish.

U.S. aquaculture production of channel catfish female (Ictalurus punctatus) × blue catfish male (Ictalurus furcatus) F1 hybrids has increased substantially due to the hybrid's improved growth, survival, carcass yield and ease of harvest compared to the more commonly farmed channel catfish. However, information on the genetic architecture underlying phenotypic variation in the hybrid which is needed to develop an efficient genetic improvement program is lacking. Progeny from two separate factorial matings between male blue catfish and female channel catfish (ten males × seven females and twelve males × five females, respectively) were grown communally in earthen ponds and measured for carcass yield and weight at approximately 520 days post-hatch. Parentage of progeny was assigned by inheritance of microsatellite genotypes. Progeny from 118 full-sib families, within 12 maternal half-sib and 22 paternal half-sib families, were measured for harvest weight (n = 1288) and carcass yield (n = 1101). Variance component estimates associated with dams (dam general combining ability and heritabilities based on dam half-sib families) were high, variance associated with sires (sire general combining ability and heritabilities based on sire half-sib families) were intermediate, and variance components associated with the dam × sire interactions (specific combining ability) were low for carcass yield and harvest weight. Data indicate that the genetic variance for carcass yield and harvest weight of F1 hybrids was primarily additive. Selection for improved carcass yield and growth based on additive genetic merit of blue catfish male and channel catfish female parents should be effective for improving performance of hybrid progeny.