Variation in development rate among clonal lines of rainbow trout (Oncorhynchus mykiss)

The genetic basis of development rate was examined using clonal lines of ra inbow trout produced by androgenesis. We examined development rate, as indi cated by physiological time to hatch (degrees days), of four clonal lines o f rainbow trout crossed to outbred females in three separate experiments. I n the first experiment, the Swanson line, derived from an Alaskan populatio n, displayed a significantly earlier physiological time to hatch than the A rlee line, derived from a domesticated rainbow trout (P < 0.001). In the se cond experiment, this trend was maintained across three temperatures (appro ximately 8, 10, and 14 degrees C) and two females, although the experiment lacked the statistical power to detect a difference(P = 0.052). In the thir d experiment, the Swanson line had a significantly earlier physiological ti me to hatch than three other clonal lines (P < 0.01) when tested across thr ee temperatures (8, 10, and 16 degrees C) and two females. There was no evi dence of genotype by environment interaction in any of the experiments. The se data indicate that development rate has a strong genetic component, and that the clonal lines of rainbow trout available should be highly suitable for QTL analysis of development rate in rainbow trout. (C) 1999 Elsevier Sc ience B.V. All rights reserved.