Paternal variation in juvenile survival and growth of the triploid hybrid between female rainbow trout (Oncorhynchus mykiss Walbaum) and male brown trout (Salmo trutta L.)

Related sib-groups of rainbow trout × brown trout triploid hybrid and monospecific brown trout controls were obtained from a common set of brown trout sires. On the basis of hybrid juvenile survival and growth, 10 sib-groups were selected and the corresponding brown trouts were raised up to adult stage. Males from each group of brown trout were used to produce a second generation of hybrid progeny, the performances of which were analysed for grandpaternal variation and relation with first generation relatives. Results showed that hybrid traits were influenced by paternal and grandpaternal origin, but that there was little relation between hybrids and brown trouts, or between successive generations of hybrids.