Response of two generations of selection to increased body weight in channel catfish, Ictalurus punctatus, compared to hybridization with blue catfish, I. furcatus, males

摘要

Growth was recorded for 75 channel catfish from each of 2 lines (Kansas, AU-KS-2, and Marion, AU-MS-2) that had been selected for increased growth over 2 generations, and an unselected control line and for 75 Channel catfish X blue catfish hybrids.Two generations of selection resulted in a 12% and 11% increase in body weight at market size, respectively, compared with unselected controls. The second generation of selection produced no improvement in growth, and there was a slight negative responseto selection for body weights during the second generation. Cumulative realized h2 was 0.17±0.03 and 0.15±0.03 for AU-KS-2 and AU-MS-2, respectively. Relative size differences were established by the time the fish reached 80 g, and these relative size differences were maintained for the remainder of the experiment. Growth rate of the hybrids was 35% faster than the Kansas control, and better than all three groups of channel catfish. The growth improvement through interspecific hybridization was three times better than through mass selection.